# Let just make an AC motor



## JRP3 (Mar 7, 2008)

It seems to me the inverter is the more difficult/expensive side of the equation. You might want to look at existing motors that could benefit from a better controller. For example, the AC31 from HPG that I'm using is limited by the Curtis controller to 108 nominal, 130 cut off. I think HPG is trying to get Curtis to build them a 144 volt unit, so they think it can go at least that high. Of course my suggestion is completely self serving 
There are some aluminum frame industrial motors that might be promising as well, of course liquid cooling is rare, so if you're set on that I guess you might have to start from scratch. I'll be interested to see what you come up with either way.


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## coulombKid (Jan 10, 2009)

Jimp said:


> I have been looking into motors suitable for my planned conversion for some time now. My wish list is very much like a lot of others. A 400 Hz, 25-30 HP cont., 100 - 200V, water/oil cooled, 3 phase induction motor less than 150 lbs at a reasonable price that can be purchased in 1 pc or 1K pc quantities with or without a controller. In summary, this motor does not exist. If anyone knows otherwise please speak up.
> My research shows that the big issue is not technical but financial. Those that have succeeded in making a suitable motor are only selling to OEMs, they are not even talking to us (DIYs). I am opening this thread with the intent of starting a project to develop such a motor.
> I propose that ownership will be with those that contribute, with commitment to always provide a way for the DIY to purchase a motor at a reasonable price. I am an EE and I intend to develop the required inverter and I am commitment to always provide a way for the DIY to purchase or build an inverter at a reasonable price. If you have talent (engineering, project management, prototyping, accounting or finance) and wish to be involved in this with similar commitment, please post-up and lets see where this goes.
> Please refrain from the endless discussion about the whys and hows right now. Later, after leaders have been taken ownership of the disciplines listed above, we will break into groups and set goals and begin those types of discussions. For the time being my wishlist listed above is the target and mission statement and even that is subject to later refinement.


 Right now is the right time to bust out the drives and motors that are purpose built. We are just three years from a cost effective bat pack. I'm a mechanical. Please consider heat pipe technology when building your motor and drive cooling means. Its a win-win active-passive thermal solution vector. I interviewed with a major Dod contractor that was developing the heat pipe technology for aircraft that don't exist. (wink) I'm also licensed for refrigerants. As a EE you are no doubt way ahead of me on embedded systems design. I've down loaded all the Microchip papers on AC drives and am currently teaching my self PASM for the Parrallax Propeller. I work for ASU as a stationary engineer and will find out if I can gain cheap access to MATLAB and LABVIEW. I may have to register as an unclassified grad student to pull it off. I have a tube of T-220 IGBTs to experiment with at home on a small three-phase motor. Being such a noob I'll be starting with open-loop volts/herts first before chinning up to encoder/hall effect feed back drive software. Everything out there right now is crude for thermal management and most will die in Phoenix heat. The multi-cog Propeller can easily cut in half the number of chips needed for a drive. Its raw power will make a lot of the assembler work arounds in the Microchip solutions unnecessary. See AN900, AN889, AN843, AN887, and AN937 on the Microchip site. I still need to down load the pub from last year done by a bunch of heavily sponsored Canadian engineering students on an AC drive for EVs.


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## Jimp (May 21, 2009)

I am not sure the AC31, at at 12 Hp continuous and $4 K, fits the need. It is under-powered by a factor of 2 and over priced by a factor of 2. 
Because motors and inverters are in some regards a matched set, I would prefer to get a little traction on the make a motor idea before I get into the details of inverter design. 
In regards to thermal management I have thought that water or oil cooling and proper spec derating is the "standard" approach. The heat pipe approach still leads to how do you disperse the heat? 
Water cooling is not a particularly tough problem, you use an aluminum fin frame, put a shell around that and pump water between the frame and the shell.
Still, these are good topics. 
One of you is mechanical, although I do not know if that is a design or prototype skill. The other or both is more interested in an inverter. That's fair, but each has something to contribute. 
Clearly there are more readers than respondents. Stay tuned we may find the talented, motivated people to yet make this a realizable project.


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## JRP3 (Mar 7, 2008)

Jimp said:


> I am not sure the AC31, at at 12 Hp continuous and $4 K, fits the need.


True but the $4K is for both the motor and controller, presumably you could get just the motor for at least half of that. I also assume the HP of the motor is limited by the controller and cooling. Improve both and I would think there should be a good potential to improve output as well.


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## Hillbilly (Jun 23, 2009)

We need to get moving on this ASAP. There is stimulus money being handed out as we speak. The money will most likely go to established companies, but if we can make a team of experts and organize into some kind of entity, we can get a shot at getting some grant money.

I have skills in business planning, project management and prototyping, as well as conections for advertising.

What I lack in knowledge, I make up for in passion, creativity and drive.

I don't care if someone steals my idea's, I just want to change the world.

Vehicle retrofit kits could be the way to go. If we can establish an entity and join the SEMA, that will give us strategic alliances.

We can start with a basic AC induction kit, then move to higher end DC hub motor kits, and everything in between.

Right now my end goal is to provide a kit to build a microturbine powered vehicle with DC hub motors at each wheel.

I just need the $100k to build it.

I agree about not debating the details, we can make proposals for everyone's ideas and let the US Dept of Energy sort them out.


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## coulombKid (Jan 10, 2009)

*Re: Let just make an AC motor (idiot resistant).*

The heat pipes lend themselves better to EVs than they did to hypersonic/pulse hydrogen burners. The horizontal section of the pipe lies in the motor stator and the vertical section acts as a reflux column up in the breeze. Duct work (where the radiator used to be) can direct the air over the tubes at road speed and an aux fan can come on just like FWD ice do now when needed (lead foot starts, slow traffic, high ambient temps). Thermal couples in the motor and switching heat sink will reduce current/power to protect the hardware but a good cooling system makes that less of an occurance. In the imortal words of Lloyd Gilbert: " If you want a robust reliable design, you have to get the stress out".


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## Tesseract (Sep 27, 2008)

JRP3 said:


> ...I also assume the HP of the motor is limited by the controller and cooling....


IIRC (though I'm sure major will correct me if I'm wrong), the power output from an ac induction motor is strictly limited by saturation of the rotor. That is to say, there comes a point where cramming more amps through the stator no longer induces more amps in the rotor. It is because flux is not directly produced in the rotor - as it is in a dc machine - that there is a much harder limit to the amount of torque that can be extracted from an induction machine.


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## Tesseract (Sep 27, 2008)

coulombKid said:


> ...Please consider heat pipe technology when building your motor and drive cooling means....


I did consider them, and strongly, for my dc controller. By my calculations I could have totally eliminated the need for liquid cooling by embedding 16 8mm heat pipes down the length of the heatsink so that the heat from the IGBT modules would be rapidly transported across the entire heat sink area. Unfortunately, the 5 or 6 companies that make them AND would talk to us all wanted $20-$50k to do a CFD analysis of our design requirements and then make the heatsink with the heat pipes embedded themselves. One company - Thermacore - makes a really cool planar heat pipe ("heat spreader") especially for high power IGBT modules... they want $500 for it. Seriously. I was on the phone with this guy and my jaw just dropped. I said to the guy, "umm, the single quantity price of the module is $300 - why would I pay $500 for a heat spreader when I can simply double up on the modules for a lot less money?" Not that I was surprised: when a website has pictures of fighter jets on it you just know your budget is in for a world of hurt.

I'd still love to embed heat pipes into the heatsink and ditch the liquid cooling passages but no one wants to sell you just the heat pipes...


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## JRP3 (Mar 7, 2008)

Tesseract said:


> IIRC (though I'm sure major will correct me if I'm wrong), the power output from an ac induction motor is strictly limited by saturation of the rotor. That is to say, there comes a point where cramming more amps through the stator no longer induces more amps in the rotor. It is because flux is not directly produced in the rotor - as it is in a dc machine - that there is a much harder limit to the amount of torque that can be extracted from an induction machine.


That may be true but since HPG is shopping for a more powerful controller for their motor I assume they feel the controller is the limiting factor at this point. I don't know how to determine the maximum power a specific AC motor is capable of other than trying it, though there probably is a way to calculate it if you know how it's constructed.


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## Jokerzwild (Jun 11, 2009)

Please consider heat pipe technology when building your motor and drive cooling means. Its a win-win active-passive thermal solution vector!

Funny you said that! My company is big into LED and we have used every type of cooling known 2 man. We have determined Heat Pipe is the only way 2 go. So my motor I am creating will containe heat pipe!


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## major (Apr 4, 2008)

Tesseract said:


> IIRC (though I'm sure major will correct me if I'm wrong), the power output from an ac induction motor is strictly limited by saturation of the rotor.


Hey Tesseract,

The torque output for the induction motor has a limit called breakdown torque. Current can increase beyond the current at breakdown, but for the increased current, torque decreases. It is a classical "induction motor speed torque curve". For a particular IM design (winding and iron), this breakdown torque (BDT) does not change with voltage or frequency. It is more a function of reactance than saturation.

You speak of power output. Power being the product of torque and RPM, one can increase power from the IM by increasing the RPM (voltage and frequency) even with the BDT limitation, up to the point of mechanical integrity and rotational losses becoming too high. Saturation will not enter into this.

I guess I'd say that for a properly designed induction motor, saturation is not a limit on power. Similar to a separately excited DC motor where the flux is held constant by the field current. One can increase the power by higher armature voltage and therefore higher RPM. With the SepEx, you can increase the power by increasing the armature current and therefore the torque up to a limit of commutation and armature distortion. Whereas with the induction motor, it is the breakdown torque limitation on armature current that gets you. Either way, it is not saturation of the main field which is the power limitation.

The above explanation is likely not 100% technically accurate, but intended to relate the ideas without consuming a lot of my time and attempting to post up lengthy equations.

And on the subject, I am not inclined to participate in these "make your own motor" threads. If you guys want to, go ahead. I kind of see it as "let's make our own tires". What's so hard about making rubber? We can do that better and cheaper than Goodyear! 

Regards,

major


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## JRP3 (Mar 7, 2008)

One difference is that Goodyear makes affordable tires that fit our needs. AC motors, not so much. I do think it's more reasonable to try and get the most out of what is already available than start from scratch. If an affordable controller can get more power out of an AC31 or some other motor I'd say that's the way to go. What Eric Tischer is doing with his Ford/Siemens motor is interesting but from what he was saying his cost will end up being pretty high.


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## major (Apr 4, 2008)

JRP3 said:


> One difference is that Goodyear makes affordable tires that fit our needs.


Yeah, JRP,

I suppose you're right. I did say "kind of like". So maybe not the best example or analogy. But you know what I'm talking about. Why not make the transmission, or battery cells, or controller? How long have we watched folks trying to make a controller? Finally after years and years, maybe somebody is getting close. But they went off and did it themselves. It was nice of them to keep the rest of us posted, even though some guys gave them a lot of crap. 

A good example of a group design effort on this forum is 

http://www.diyelectriccar.com/forums/showthread.php/open-source-hub-motor-wheel-motor-14185.html 

435 posts and 61,975 views later, we got nothing. Just my opinion. Prove me wrong, please. 

major


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## Bugzuki (Jan 15, 2008)

I would be happy to participate in this project. My interest really is in the AC induction motor. 

The problem all the other motor project threads have had is that nobody will agree on a starting plateform and stick to that until there is a prototype.

I think that it would be great to incorporate high tech devices like heat pipes. But, I think that we should focus on getting a motor running before we get caught up in developing something that we might not be able to do feasibly. That can be added later and developed in parallel in a different thread.

Since this thread is called "Just make an AC Motor" it should focus on that until we are ready to incorporate the heat pipe if that is the direct we go. 

I think the first thing that needs to happen is to develop a requirements statement. Jimp since you started this thread are you willing to drive the direction? Extra functionality can be added to the secondary requirements so they do not get lost, but basic motor functionality needs to come first.

I have a Ford/Siemens motor I can use to get a starting point from if you want.

Major: You posted while I was writing, but the thread you sited was exactly what I was thinking about. That is exactly what I want to avoid again. A lot of wasted time. What type of Transmission are you interested in? That is a big project.


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## Bugzuki (Jan 15, 2008)

I would also be willing to make up some CAD drawings. I own a fully licensed perfessional version of Pro/Engineer. 

This cuts out possible issues with using Pirated Software. If anyone else has a license to anonther CAD tool I would be happy to develop in parallel, student versions are pushing the limit of what the laws allow. 

I also do not want this project developed using any computer that belongs to an outside entity. (like: I work for a large international company. They own CAD software and many computers. I signed an agreement that anything developed using their equipment is legally theirs.) I do not want to loose this project because of this. I am sure this same thing applies to others out there.

Lets actually design something.


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## Jimp (May 21, 2009)

Major. you sound jaded, which is too bad because you seem to know more than most about motors. I hope you keep reading and help where you can.

In my opinion, in order to develop any useful product you need to first have an idea. In this case it is a 400 Hz, 25-30 HP cont., 100 - 200V, water/oil cooled, 3 phase induction motor less than 150 lbs. 

Second you need the required talent such as engineering, project management, prototyping, purchasing, accounting or finance

Third you need the needed resources money, software, time.

Group projects tend to fall apart for a number of reasons, such as unclear focus; no capital; no clear leadership.

Currently we are in the find talent mode. To this end, anyone wishing to work on this please send to me an email explaining which group that you wish to be in, your experience and do you wish to be a leader. Do you wish that your involvement be confidential? I will post summaries.

We need a mechanical engineer to lead the rotator effort, the stator effort and housing effort. We need a model and or simulation, drawings, material lists. We need to find qualified machining, stamping and casting services. We need the money to buy manufactured components. We need to design,fab,build and test. We need to evaluate costs and profitability and we to account for everyone's contributions for fractional ownership. Most of all we need to trust one another. We need to act in ways that build trust.


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## Jimp (May 21, 2009)

Since I have been tasked with the requirements. Let's dig into that.
In a gross sense we need a light weight powerful motor. Since this is not new technology, we will borrow from known technology.

400 Hz - This is a standard operating frequency. It is high enough to keep the required iron laminate stack small and therefore light weight. 

3 phase - This is also a standard which is required to get enough electrical energy into the motor.

25-30 Horse power continuous - Although it takes 15 HP to move my car, I wish to have a little power to spare. 

Water/Oil cooled - This may be optional, but I do not think so. Light weigh implies small. Small implies less surface area. Less surface area implies less heat transfer. Fan cooled may be an option but may be less reliable than water cooled. 

100V - 200V This is a compromise between high currents with heavy wire and high voltage with many batteries. 

80 lbs. This is the target weight. 

25 HP = 18.6 KW, 30 HP = 22.4 KW or {18.6K, 22.4K} at 90% efficiency electrical power is {20.6, 24.9} KW with {2,2.5} KW lost as heat. 

{100,150,200} Vrms = {141, 212, 282 ) V pk at 3V/cell {47,71,94} cells.

60AH cells rated for 3C discharge = 3 * 60 = 180 A *{100,150,200} = {18, 27, 36} KW closest but over req. is 150Vrms, 212Vpk,71cells.

These requirements are now open to discussion.


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## JRP3 (Mar 7, 2008)

Something to consider in regards to weight and air cooling, ACP gets 150KW max, I think 50 continuous, out of a 110lb motor, Tesla does even better out of a 70lb motor, both with air cooling. Of course they run much higher voltages.


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## tomofreno (Mar 3, 2009)

So what are the differences in these motors, and between them and the AC31 which is heavier and lower power? I don't see how you can design a motor if you don't understand the details of that.


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## mmark666 (Feb 21, 2009)

Jimp,

just curious, what do you mean by a standard operating frequency of 400 Hz? Do you mean that this is frequency to drive the motor to the maximum rpm? I would specify the maximum rpm and the number of poles, than the required (maximum) frequency can be easily deducted...

One other thing: Don't design the cooling assuming the best efficiency. If you somehow stall the motor, all the electric power will be converted into heat (efficiency = 0%!!!)... The reality will be somewhere in between, so there should be a big safety margin on the cooling... (and active temperature control of course).

And finally: I have the "feeling" that BLDC have some advantages over AC motors in electric cars, so I would consider developing this instead of an AC motor...

Cheers,

\m/arkus


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## Bugzuki (Jan 15, 2008)

Jimp said:


> Since I have been tasked with the requirements. Let's dig into that.
> In a gross sense we need a light weight powerful motor. Since this is not new technology, we will borrow from known technology.
> 
> 400 Hz - This is a standard operating frequency. It is high enough to keep the required iron laminate stack small and therefore light weight.
> ...


 
That is a good start. Exterior dimensions are needed to define so that we can make the design within the required size constraints. We can always go smaller but we need to decide on the maximum size.

100 to 200v is a good starting point. I would like it higher but that can be done later. I think it is more feasible for most people to have it so that they can put 12 12v batteries in and be good to go.

I also think that we need to specify the max RPM and number of poles. I would like to have a motor that can go to higher RPM like 8 or 10k. In the car I build we had a that went 8K. We originally had two speeds but found that it had good acceleration in 2nd and could go freeway speeds. Less shifting = better

The poles are kind of tied to the rotor diameter and wire size but that is a very important factor in the motor design and sizing.


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## JRP3 (Mar 7, 2008)

mmark666 said:


> And finally: I have the "feeling" that BLDC have some advantages over AC motors in electric cars, so I would consider developing this instead of an AC motor...
> 
> Cheers,
> 
> \m/arkus


Both ACP and Tesla would disagree. Tesla took a long hard look at both technologies and decided on AC induction. They wrote a pretty good blog on the comparison and why they chose the way they did. Probably still on their site somewhere.


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## JRP3 (Mar 7, 2008)

I think it makes sense to be able to use the most common mounting dimensions, Warp9/ADC9, so as to fit existing adapters. That's what HPG did with their AC31.


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## mmark666 (Feb 21, 2009)

JRP3 said:


> Both ACP and Tesla would disagree. Tesla took a long hard look at both technologies and decided on AC induction. They wrote a pretty good blog on the comparison and why they chose the way they did. Probably still on their site somewhere.


Hmm,

according to Wally Rippel's blog on tesla.com (http://www.teslamotors.com/blog4/?p=45) he sees no clear winner:



> *
> Still No Winner*
> My conclusion is that DC brushless drives will likely continue to dominate in the hybrid and coming plug-in hybrid markets, and that induction drives will likely maintain dominance for the high-performance pure electrics. The question is what will happen as hybrids become more electrically intensive and as their performance levels increase? The fact that so much of the hardware is common for both drives could mean that we will see induction and DC brushless live and work side by side during the coming golden era of hybrid and electric vehicles.


Since a 30HP motor hardly is a high performace motor, I still think that a BLDC motor might have some advantages for THIS application. Also I believe that the controller might be a little easier (not the hardware, but the software).

The fact that Tesla can get so much perfomance out of their "tiny" AC motor is just amazing. But I don't think that we/you will be able to match that in a DIY project. Please prove me wrong!! 

\m/arkus


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## JRP3 (Mar 7, 2008)

Well the fact they chose induction over brushless says a lot, as does the following:


> In an ideal brushless drive, the strength of the magnetic field produced by the permanent magnets would be adjustable. When maximum torque is required, especially at low speeds, the magnetic field strength (B) should be maximum.....Unfortunately, there is no easy way of changing B with permanent magnets.....In contrast, induction machines have no magnets and B fields are “adjustable,” since B is proportionate to V/f (voltage to frequency). This means that at light loads the inverter can reduce voltage such that magnetic losses are reduced and efficiency is maximized. Thus, the induction machine when operated with a smart inverter has an advantage over a DC brushless machine – magnetic and conduction losses can be traded such that efficiency is optimized.....peak efficiency will be a little less than with DC brushless, but average efficiency may actually be better.....
> Permanent magnets are expensive – something like $50 per kilogram. Permanent magnet (PM) rotors are also difficult to handle due to very large forces that come into play when anything ferromagnetic gets close to them. This means that induction motors will likely retain a cost advantage over PM machines. Also, due to the field weakening capabilities of induction machines, inverter ratings and costs appear to be lower, especially for high performance drives. Since spinning induction machines produce little or no voltage when de-excited, they are easier to protect.


A 30HP motor could be high performance if that 30HP comes out of a small package.
I doubt a home built motor will come close to what Tesla and ACP have done but it would seem to make sense to head in the same direction. Frankly I doubt anything will come of this exercise but I think it's an interesting discussion and I might learn something along the way.


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## caspar21 (Apr 8, 2009)

the objective WAS to make something that anyone could build with the produced plans, correct?


for a DIY project, not having to deal with expensive/dangerous magnets is a good thing..

AC seems to be a better idea than BLDC for this reason alone.

i saw a DIY home made windmill design that was very dangerous for the builder due to the powerful magnets wanting to come together with no care of what is in the way. that scares me.


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## Bugzuki (Jan 15, 2008)

I don't think there needs to be a discussion on which to design. The title says AC. If you don't like that go start a thread called BLDC. This thread is about AC induction machines lets leave it at that and get on with planning the motor.


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## Jimp (May 21, 2009)

I have been away from this for a few days. 
It seems that we have wrapped up another lively but unrelated discussion. 

Higher RPM has good and bad points. Good - less motor torque. Bad - may need a transmission, bearings get hotter. I had hoped for my conversion to eliminate the transmission and change the differential gear ratio. I am not trying to open another stray topic with this. Just musings.

If there are no specification issues, we can more on to high level details. 

I will defer to Bugzuki to lead this discussion. 

Can we now discuss and firm up the specs on size and number of poles ?

What I have seen in the literature says that you lose efficiency with number of poles. I would suggest 6 poles as a compromise. 

I am uncomfortable with "let's use their size". Although I am not a mechanical engineer and do not know the answer, my question is: how do you calculate the optimum diameter and length? Do you start with the rotor or stator ? I know longer will incur higher stator wire losses, but will give higher magnetic cross sectional area to the poles, with lower flux density and higher inductance. A larger diameter means more material cost but gives more room for the stator wire. 

About the stator wire, as a starting point 180 A * 1.3 (margin) = 234A. 234A * 300 cir. mils / Amp = 70200 cir mils. = #1 AWG mag wire. 

This is where a purchasing person would come in and I would ask for the price and availability of double or quad insulated 1 AWG class H mag wire. If some one would find the answer to this it would be nice. 

The diameter is about .3 in.; resistance is .124 ohms/Kft; weight 3.95 feet/lb 

Please note that 300 cir mils/ amp is NOT conservative. this will run hot.


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## Jimp (May 21, 2009)

Ram Industries makes copper bar rotors their # is 800 999 8183.


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## Tesseract (Sep 27, 2008)

You might find this site interesting:

http://demonstrations.wolfram.com/ACInductionMotorRotorDesign/


The design of the rotor is critical; the stator is downright simple in comparison: it just needs the pole pairs spaced 120 degrees apart and with the right number of amp-turns.


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## Jimp (May 21, 2009)

laminations are available here:
http://www.etimotors.com/laminations.htm


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## Jimp (May 21, 2009)

mmark666 said:


> Jimp,
> 
> just curious, what do you mean by a standard operating frequency of 400 Hz? Do you mean that this is frequency to drive the motor to the maximum rpm? I would specify the maximum rpm and the number of poles, than the required (maximum) frequency can be easily deducted...
> 
> ...


The commercially available motors ie Baldor have 25 HP 60Hz motors that weigh over 500 lbs. 
400HZ engineering has a ME-440 motor at: http://www.400hertz.net/Products/ME-440.htm 
which is 40 lbs and 30 HP, I spoke to Ed Dempsey, he's been doing motors since 1961 and he's a great guy.
The weight difference, as far as I can tell, comes principally from the higher frequency operation. 400Hz is the AC frequency used by the aviation to keep the weight of generators down. Submarines also have a 400HZ AC system.


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## ereth (Jul 11, 2009)

Seems to me that the Siemens spindle motors for CNC machines are about the right fit and would be a good design guideline. They operate at high frequency and RPM, are compact, and are available with liquid cooling. Note the physical similarity to the Siemens/Ford EV Ranger motor.

http://www.automation.siemens.com/mc/mc-sol/en/f7642c37-0b26-48ff-ae00-c0b0a548ed17/index.aspx

A laminated frame design seems to be the way to go for compact powerful motors. I see the development work as having two parts.

One: a rotor with a higher than standard critical speed needs to be specified. This seems like pretty standard type of requirement for a "custom" rotor that numerous on-shore rewind/motor companies could produce. Since this motor will only see service connected to an electronic drive the rotor torque vs slip curve should really be optimized for the highest peak torque and the rest isn't too critical.

Two: a stator/laminated frame need to be designed. From a production/assembly perspective this is really just the same as producing the core for a more traditional motor. The laminations for the core are simply extended somewhat and contain extra holes for coolant channels and structural reinforcement bars. Again, it looks like many rewind/motor companies have the facilities to produce prototypes and low volume.

To crash the project you can start with a traditional off-the-shelf motor and develop the two parts in parallel. Spec out a new rotor for the motor with the same physical dimensions and install it in the existing frame for testing. At the same time, develop the new stator/frame to accept the same physical dimension rotor and test it with the existing rotor. Once both parts are available you can install the new rotor in the new stator/frame and test. Doing this in parallel means that the development schedules for both the rotor and stator/frame are not tied up waiting for each so you get at least one "free" iteration in terms of scheduling. Also, testing is simpified because you are testing each component individually and have eliminated any variables associated with the stator for initial rotor testing and vica-versa for the stator testing.

Overall seems like a reasonable project. More research is required in order to get an idea of development costs.


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## yendrek3 (Jul 11, 2009)

Jimp said:


> I have been looking into motors suitable for my planned conversion for some time now. My wish list is very much like a lot of others. A 400 Hz, 25-30 HP cont., 100 - 200V, water/oil cooled, 3 phase induction motor less than 150 lbs at a reasonable price that can be purchased in 1 pc or 1K pc quantities with or without a controller. In summary, this motor does not exist. If anyone knows otherwise please speak up.
> My research shows that the big issue is not technical but financial. Those that have succeeded in making a suitable motor are only selling to OEMs, they are not even talking to us (DIYs). I am opening this thread with the intent of starting a project to develop such a motor.
> I propose that ownership will be with those that contribute, with commitment to always provide a way for the DIY to purchase a motor at a reasonable price. I am an EE and I intend to develop the required inverter and I am commitment to always provide a way for the DIY to purchase or build an inverter at a reasonable price. If you have talent (engineering, project management, prototyping, accounting or finance) and wish to be involved in this with similar commitment, please post-up and lets see where this goes.
> Please refrain from the endless discussion about the whys and hows right now. Later, after leaders have been taken ownership of the disciplines listed above, we will break into groups and set goals and begin those types of discussions. For the time being my wishlist listed above is the target and mission statement and even that is subject to later refinement.



well, i know from my short experience that making your own nits anf pieces is a very costly thing. Even if you are an inventor it will cost loads to get what you want. I would rather use one of the ready prepared motors


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## Bugzuki (Jan 15, 2008)

This is starting to get interesting. I think I will have some time this week to pull out my motor and do some checking into it. Jimp what did you want to differ to me?


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## caspar21 (Apr 8, 2009)

yendrek3 said:


> well, i know from my short experience that making your own nits anf pieces is a very costly thing. Even if you are an inventor it will cost loads to get what you want. I would rather use one of the ready prepared motors


umm.. not if what you are making is seriously over priced as AC motors are.


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## yendrek3 (Jul 11, 2009)

Hi,

I'm with you guys. If you have a funds to develop new thing then go for it. As mentioned above I know from my own experience that development costs a fortune but I like the idea of inventing new things. Anyway I wish you all the best and look forward to see your results. I'm very curious how that goes?


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## ereth (Jul 11, 2009)

This manufacturer looks looks interesting.

http://reuland.com/index.html

One of the products they list is partial motors that are just the rotor and stator to be integrated by the customer. If someone like Reuland can design and deliver the guts of the motor why not just concentrate on developing a light-weight, liquid-cooled frame? And maybe some sort of system for integrating output bellhousings and/or adaptor plates?


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## Bugzuki (Jan 15, 2008)

I am sending Reuland an email to see if I can get some details on there partial motor's and if I can get pricing on a couple different sizes. Like 30, 50, 70, 100 and 150 horsepower units. 

If they are a reasonable price and are willing to sell in low quantities that might be a good option to start this project with.


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## yendrek3 (Jul 11, 2009)

Bugzuki said:


> I am sending Reuland an email to see if I can get some details on there partial motor's and if I can get pricing on a couple different sizes. Like 30, 50, 70, 100 and 150 horsepower units.
> 
> If they are a reasonable price and are willing to sell in low quantities that might be a good option to start this project with.


well Bugzuki,

if the prices aren't too high then go for it. It looks like these motors could have some good use. BTW Does anyone know if these electric motors are reliable?


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## Jimp (May 21, 2009)

What you guys are talking about is usually called a frameless motor. You buy the rotor and stator to integrate into your device. I also looked into rotors, I tried to email a company called RAVI in France but got an "unauthorized" bounce. If they have an off the shelf rotor it would be a big leg up. I defer to Bugzuki to lead the high level design part of this discussion. Motor design is not my specialty and I am putting more time into the inverter design to go with this. 

Does anyone know a purchaser to get involved with this project? 
Does someone want to "own" the task of looking into price / availability questions?

Eventually the issue of money will have to be addressed. I have $2K or so for this that I can put at risk. I can go to $5K or so if I receive the motor that I will use. Eventually we will be passing the hat, everyone should be prepared to answer this issue in a similar form to the way that I have.


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## Jimp (May 21, 2009)

It seems to me that Reuland does not make copper bar rotors. 
This is one of the high efficiency issues. 
Their high speed pdf shows a 215T, 50 HP, 1.8K Hz at 60Hz drive, 14K Hz at 466 Hz drive, liquid cooled, looks like a good candidate for a 'partial' purchase. Change to a copper bar rotor, design and fab housing, bearings and end bells and we might have a prototype.

I have started on the inverter design. I have a power, isolation/driver and controller section conceptual design done. The base-line controller comes with space vector modulation, regen and USB in the code. The prototype will be very over-designed for voltge, current and heat. I may start a similar thread to this one in the controller/inverter space, or I may just finish this myself. 

I have recruited an additional mechanical engineer off-line. 

I currently do not have anyone with the ability and software to do the E/M modeling, this is a high priority! 

We still do not have the key leadership (default worker bee) positions un-filled ! 

Such as purchasing ( how much does this XXX cost ), accounting ( keep track of contributor's input for partial ownership, finance ( beg for money for small partial ownership), project management ( beg everyone to do what they promise in a reasonable time), prototyping ( builder and tester ). A current criteria is a simple private message to me, stating your desire to participate, level of participation, type of participation, and qualifications, name, email address and phone number. I have no interest in exposing your involvement to anyone outside this team. 

Once this core group is established, off-line we will decide how to payback investors ( which may be only us ) and how to offer the motor to the DIY community. I am leaning toward plans, kits and motors. Please review the early thread for the mission statement. 

Please recruit friends and family for the non-technical positions !

From what I can tell, the number one thing that Tesla and some others did to achieve high power in a small package was to optimized the cross sectional shape of the copper buss bar rotors and use low hysteresis loss stator/rotor laminations for high drive frequency operation. I do not expect to duplicate their achievement with the resources at hand but I do expect to meet our HP/weight goals.


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## DBabs (Jul 14, 2009)

Jimp said:


> ....We still do not have the key leadership (default worker bee) positions un-filled !
> 
> Such as purchasing ( how much does this XXX cost )...


JIMP, Purchasing position - as we spoke earlier, I'm very much interested. I have the know-how, and cost-control is one of my specialties.


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## DBabs (Jul 14, 2009)

Favi - Their contact list for the US is at 

http://www.favi.com/ang/accueil.php?msg=agusa


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## celsomenaia (Jul 26, 2007)

hello 

electric motors and alternators used on air planes auxiliary systems are 400 Hz, so because they are lighter compared with 50/60 Hz motors


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## vwdevotee (Mar 8, 2008)

mmark666 said:


> just curious, what do you mean by a standard operating frequency of 400 Hz? Do you mean that this is frequency to drive the motor to the maximum rpm?


 
Um, so I'm a newbie, but I had this same question. Can anyone point to a thread or provide a simple answer?


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## Morf (May 29, 2009)

Hi Jimp,
Speaking up here, about a 3 phase, 80 volt Exide Battery powered, AC Propulsion logo motor used by Toyota Industrial Equipment. HP is 23.3, KW is 16.6. It has a 60 minute rating towing 55,100#. See the Toyota brochure for their 2TE18 airport and/or factory tow. They will ask for a serial number on the vehicle it is to go into. Another 3 phase, 80 volt, on the Jungheinrich fork lift. My requirements are for a motor that will propel a Modec type van and I am looking at an impressive Oswald watercooled FQD13.3, available in 50 or 70HZ, Continuous duty, 42 HP., 32 KW, 7500 RPM, 209NM =153# pounds of torque. I am loosing weight so I can feel OK about it`s 320# s. Hyster has a 3 phase in a fork lift, and there are two more fork lifts in Toyota`s list that also carry the AC Propulsion logo over the motors. I am not wise enough to know if any of these are interesting to you. The price on buying 5 units of the Oswald is seductive, but I do not see a large number of EV van enthusiasts out there who would knock down the door for the other four. Would that Oswald pull an aluminum aerostyled van up a hill or not?


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## Drew (Jul 26, 2009)

I'm sorry to go a bit off topic, but are there any motors which use aluminium wire for the stator? 

The reason I'm asking is because it would seem to me to be a very high cost and mass saving if you could do that, I've seen some speakers where they made up for losses associated with it by going to square or hexagonal wire for greater stacking density.


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## yendrek3 (Jul 11, 2009)

Drew said:


> I'm sorry to go a bit off topic, but are there any motors which use aluminium wire for the stator?
> 
> The reason I'm asking is because it would seem to me to be a very high cost and mass saving if you could do that, I've seen some speakers where they made up for losses associated with it by going to square or hexagonal wire for greater stacking density.


Good questions but I have no idea if you can get them actually? Normally all wiring is copper but I have never seen the aluminium ones


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## caspar21 (Apr 8, 2009)

discussion continues! woohoo!


Pro's of using aluminum wiring:
much cheaper
lighter


problems i see with aluminum wiring in a motor (according to my limited knowlege) is:
lower heat transition values
higher resistance (increasing the kw required for the same effect)

question for those that know:
would aluminum stretch more than copper limiting max rpm?


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## vwdevotee (Mar 8, 2008)

yendrek3 said:


> I have never seen the aluminium ones


I would beg to differ. If you've seen power poles, you've seen aluminum wire. The power grid is based on it because it is lighter weight and they are able to use fewer poles as a result. 



One of the difficulties in using aluminum wire is that it work hardens with age (and stress/strain) and becomes brittle. This could lead to cracking in the wire and at best a break in the wire, and at worst a bit of it snagging in the rotor at high speed. 

Call me a kermudgen, but I think for a DIY project like this people should stick with proven materials and leave the R&D to big companies with deep pockets.


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## Jimp (May 21, 2009)

Generally aluminum wire are not used for stator windings as the resistance of the wire is higher with its ensuing more heat.
I could not find information on the Oswald motor (not on Google). I am not interested in 300 lbs motors.


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## vwdevotee (Mar 8, 2008)

Who said anything about a 300 lb motor? Obviously copper wired motors can be made sufficiently light to satisfy EV duty. Otherwise AC Propulsion and/or Tesla would be S.O.L. Maybe I'm mistaken, but it looks to me like the weight difference from copper wires to aluminum wouldn't be enormous. The difference between the materials looks promising, but the windings dont look to be the majority of the motor weight.

Was this the company you were looking for? http://www.oswald.de/index.php?id=2&L=1 They appear to have some relatively lightweight motors for the power.


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## Jimp (May 21, 2009)

Vwdevotee: sorry about that, I was responding to Morf's post about his candidate motors. 
About aluminum wire, I am sure that it can be done. Like I said the aluminum wires have higher resistance. They also melt at a much lower temperature. I think that you would have to derate the motor relative to a copper wire motor. 
The direction that I am taking is for highest efficiency with a higher material cost. Copper rotor bars, cobalt steel lamination, and copper wire wound stators. Things are moving slow in the motor design due to the high cost of the design software, Motor-Cad, RMxprt etc., until we find someone with the software, we are doing everything by hand.

Jim


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## Jimp (May 21, 2009)

Morf,
The FQD 13.3 is 145Kg = 319 lbs. it is also 400V. It might be OK. It seems to me that this is not a motor designed for the EV application, but rather a force fit. Just my opinion. I am trying to design and prototype a 80 lbs 50 HP motor.


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## vwdevotee (Mar 8, 2008)

Check out COMSOL multiphysics. I used it for my masters thesis and I know that one of there demo's is a motor (they make full files available to fiddle with). It looks to be an induction motor, but I can't guarantee it. They're pretty liberal with demo DVDs that have about $50,000 worth of software. It's basically everything they sell, but you can only get a couple of weeks with it. You might be able to get a couple of demos to do the bulk of your work if you talk to some friends too.


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## Morf (May 29, 2009)

Jimp,
Recently I have located a maker of 37, 45, and 250 KW Axial Gap/Flux motors in Finland. If you are considering a variety of motor sources this company is the only one I have found that makes commercial Axials anywhere near this range. The town they come from has a tec. college, and the production of these motors grew out of the school working on advanced ideas in motor design. I was sidetracked when I would use keywords ``pancake`` or `Lynch`in my search engine, which always took me to small motors, many links to 10 inch racing cars. The Axco information and charts show these Axials in industrial performance situations running at 6000 rpm for the largest one, and for the 45KW showing good torque up and through 8500 rpm. I am sending a fax to the company since their email is rejected by my computer as being too long-cannot send. However they are on the net at: Axco Motors OY, I always throw in `Finland` at the end. 
The address for Oswald in Germany is: Oswald Electromotoren LLC for finding a pdf with their complete line, both air cooled and liquid cooled. 
My project will be an aluminum straight rail frame with a pancake motor driving a conventional rear axle. I will allow a bit more weight because of using a commercial style aluminum van body. 
With an Axial Flux, all the windings are on the stators. I believe all that I have looked at so far are copper wound, but that is more guess than fact. Best Wishes.


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## caspar21 (Apr 8, 2009)

wow.. i like that Axco Motors OY technology.
http://www.axcomotors.com/axial-flux_technology.html

looks like a good way to get higher RPM without the problem of throwing a winding.

looks like it spins perm magnets with coils on the front and rear of the magnetic rotor.
only problem i see is a possibility of larger rotational mass for a big flywheel effect.

have we decided on a motor format yet?


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## Morf (May 29, 2009)

Hi Caspar21,
The `case open` views of motors that are shown by Axco Motors website do not give a good view of a basic axial flux motor. Most larger axials, and all of their motors that they show, are constructed with the stators containing the windings. Then many other combinations limited only by the imagination are makeable, but this is the classic since the new magnets came along in the late 1990s. I have seen where moderate sized motors are spec.ed around 14000. The 250 model with 300# torque, and 340 hp has a nominal rpm of 5800. I am still learning. If you come upon something interesting in the larger axial motors, please let me know. I just received an email from an Italian company which says they will be puting out a catalog of their axial flux motors soon. Best Wishes,


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## Morf (May 29, 2009)

Hi Caspar21,
I just ran across something I did a while back that might interest you. Try feeding your search engine <Axial Flux Engine> and see if you get a major spread pdf from a couple of guys in lab coats who have assembled an axial designed with car power exclusively in mind. If that isn`t quite your interest, keep going with the other threads, `cause there is some really good stuff under that heading. I like their thoughts about torque that eliminates all the gears. Cheers.


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## coulombKid (Jan 10, 2009)

Tesseract said:


> I did consider them, and strongly, for my dc controller. By my calculations I could have totally eliminated the need for liquid cooling by embedding 16 8mm heat pipes down the length of the heatsink so that the heat from the IGBT modules would be rapidly transported across the entire heat sink area. Unfortunately, the 5 or 6 companies that make them AND would talk to us all wanted $20-$50k to do a CFD analysis of our design requirements and then make the heatsink with the heat pipes embedded themselves. One company - Thermacore - makes a really cool planar heat pipe ("heat spreader") especially for high power IGBT modules... they want $500 for it. Seriously. I was on the phone with this guy and my jaw just dropped. I said to the guy, "umm, the single quantity price of the module is $300 - why would I pay $500 for a heat spreader when I can simply double up on the modules for a lot less money?" Not that I was surprised: when a website has pictures of fighter jets on it you just know your budget is in for a world of hurt.
> 
> I'd still love to embed heat pipes into the heatsink and ditch the liquid cooling passages but no one wants to sell you just the heat pipes...


I found a heat pipe assembly at the local computer store that bolts onto your souped up over-clocked gamer CPU. The boiler pipe is bolted to the top of the CPU. The copper reflux leg sticks up in the air flow with an aluminum radiator fin pack pressed on to it. Simple, cheap, effective. You would need at least 8 of them at twice the size pressed into the aluminum jacket around your stator laminations. Air flow through the grill would take care of business quite well.


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## caspar21 (Apr 8, 2009)

Morf said:


> Hi Caspar21,
> . Try feeding your search engine <Axial Flux Engine> and see if you get a major spread pdf from a couple of guys in lab coats who have assembled an axial designed with car power exclusively in mind. .


ruh roh.. i don have IEEE access to see it.

i like the idea of no gears too. AC is flexible enough that you can get good torque down bottom while still having hi RPM for top speed.


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## coulombKid (Jan 10, 2009)

caspar21 said:


> discussion continues! woohoo!
> 
> 
> Pro's of using aluminum wiring:
> ...


The Aluminum wire is in the stator so I don't see a concern on stretching. It's conductivity advantage has to do with amps per pound, not amps per circular mil. On a high tension line where weight is a concern but space isn't, by all means use aluminum. In an AC motor connection integrity is harder to maintain and reliability will suffer. Also the cube of the motor for a given horespower will grow if you use aluminum. Using aluminum will increase the size and weight of the stator laminations to attain a given flux density across the air gap. To maintain high propulsive effeciency I recommend the team stick with copper.
As for 400 hz, probabily a good thing. Army generators supporting missle batteries used to be 400 hz because the power for the computer systems was much easier to regulate and control. Current chip sets should be able to keep up with the carrier frequency required to generate drive frequencies in the 400 Hz range. Faster motors are lighter motors. Higher drive voltages would also be a good thing. Current commercial technology uses 480 VAC a lot in the 30 hp range. A 600 VDC pack is a pain to build but insulation weighs less copper and a 480 VAC based system cuts copper weight in half. Fuses and breakers also get lighter. Any IGBT you wish to use is 600 Volt rated in its cheapest rendition now. Only the US and Japan cling to low voltage three-phase these days. The automotive standard bat pack in a decade will be 600 volts worldwide for all the reasons listed above.


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## caspar21 (Apr 8, 2009)

coulombKid said:


> Any IGBT you wish to use is 600 Volt rated in its cheapest rendition now. Only the US and Japan cling to low voltage three-phase these days. The automotive standard bat pack in a decade will be 600 volts worldwide for all the reasons listed above.


I like the thought of going up to 450+V. 
it would be lower current and have lighter requirements for wiring
than a 1000+amp 144V system.
less losses in the cabling runs from the rear pack too, means less heat
in the wires.

i know higher voltage makes the home DIY builder nervous but the benefits are obvious.

any progress being made on armature designs?


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## coulombKid (Jan 10, 2009)

caspar21 said:


> I like the thought of going up to 450+V.
> it would be lower current and have lighter requirements for wiring
> than a 1000+amp 144V system.
> less losses in the cabling runs from the rear pack too, means less heat
> ...


 Typically the high efficiency commercial three phase motors have copper bars in them especially in the big sizes. Recently we had a rotor repaired at work. The chiller motor is rated at 1,600 Hp. One of the rotor bars had come loose and the vibration showed up on the monitor. In the last few years the process for pouring a copper cage on the rotor laminations has been brought to the market. It should be even easier to get a high RPM rating on a copper bar rotor than it is on the common aluminum bar rotors we have everywhere. I love the AC brush-less motors but I doubt the energy savings would ever pay-back the up-front costs.


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## theCR4NE (Aug 10, 2009)

I am also looking for a decent AC motor at a decent price. I emailed Brusa to ask about pricing, and I got a response that included their pricing (currently way too rich for my blood) and the following text:

"Please note that with those units you get the most advanced electric drivetrain technology available on the market. They are manufactured in sample volumes yet and bear a considerable amount of development costs. As soon as they're industrialized and manufactured in the intended quantity, which will be the case in the longer run due to our recently announced cooperation with Magna Electronics, we expect a really competitive cost structure.

I hope this information is sufficient; should you have further questions, please don't hesitate to ask"

I don't know what the timeline is like for this, but it sounds like they'll be mass producing these soon, and the price will drop significantly. It remains to be seen whether the cost comes down far enough for most of us, but at least there's something to look forward to.

-theCRANE


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## coulombKid (Jan 10, 2009)

theCR4NE said:


> I am also looking for a decent AC motor at a decent price. I emailed Brusa to ask about pricing, and I got a response that included their pricing (currently way too rich for my blood) and the following text:
> 
> "Please note that with those units you get the most advanced electric drivetrain technology available on the market. They are manufactured in sample volumes yet and bear a considerable amount of development costs. As soon as they're industrialized and manufactured in the intended quantity, which will be the case in the longer run due to our recently announced cooperation with Magna Electronics, we expect a really competitive cost structure.
> 
> ...


The information I read on a cast copper bar rotor was from a European manufacture (of course).


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## coulombKid (Jan 10, 2009)

To see pictures of an axial flux motor used as an alternator in a 20' diameter wind turbine see http://www.otherpower.com.


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## Morf (May 29, 2009)

To Those Who Might Build Their Own Motor,
If you haven`t already seen this site, look at what the little town of Greenville, Ohio has for you. Ramco Motors has a page showing all kind of electric motor parts that they will make for your project, including a copper cast armature, if you want your own Swiss motor. They claim to work for defense, and Nasa, I believe. To me that indicates copper castings without the internal bubbles, or copper castings without dilution. Anyway it is a very nice looking page, and they don`t seem to put any limits on what can be done for the customer. www.ramco electric motors What do you think? Best Wishes,


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## caspar21 (Apr 8, 2009)

looks expensive..

still need the people capable of developing a prototype to talk to us..


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## Morf (May 29, 2009)

Hi Caspar21,
I don`t know if a genaric prototype would want a Brusa type armature or not, but when one reads about the complexity of making copper castings that would come out uncontaminated and bubble free, it seems like the expense is inevitable. There is the problem of copper`s really high melting point, the speed that must be used to process the cast, and much more. These ideas can be considered before deciding who should do a prototype, because the processes mentioned above would limit the potential maker to the select few in an exclusive club who can do this kind of work. The copper association provided the funding, special laboratories, and doctoral level personel to carry out this work some years ago. My 75KW axial Flux prototype from Finland, adapted from an existing motor that now lives on a series of rotary screw compressors, will cost-if I have translated the information correctly??, 3500 Euros, including extensive retesting by a technical university staff before being released for the job of powering a vehicle. Best Wishes,


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## caspar21 (Apr 8, 2009)

Morf said:


> Hi Caspar21,
> These ideas can be considered before deciding who should do a prototype, because the processes mentioned above would limit the potential maker to the select few in an exclusive club who can do this kind of work.


i appreciate the input.. however this is not my thread, and i do not wish to take it over as i am under-qualified in all aspects of this project except web/forum trolling. 

if the originator of this thread will drop us a note then perhaps we can find a way to do more than discuss possibilities.


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## caspar21 (Apr 8, 2009)

i have pm'ed Jimp and not gotten a response. is there anyone else that
has an opinion concerning getting this moving again?

i will be happy to moderate the AC motor adventure here, i just wish i had the "ok" from the originator of the thread.

lets not let this die just because someone has not responded.


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## JRP3 (Mar 7, 2008)

This is a public forum, post anything you want as long as it's reasonably on topic.


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## simey_binker (May 13, 2009)

I've been reading posts on this site for a while now, although haven't been here in a few months. good to see there are still ambitious people about.

I'm an ME, and am very interested in building a production EV from the ground up. I think the best thing that pushes ANY project into action, is working within close proximity to one another. for those who have endless conference calls with people in other cities, you know how frustrating the lack of productivity can be compared to simply chatting with someone face-to-face and working with them in the same lab/shop.

in my case, I'm currently in Toronto. for those who would like to dream big and start building (in this case; an AC motor/controller from scratch) and live in Toronto, feel free to contact me. otherwise, this online discussion may fall short to only discussing "hypotheticals" and be used as a resource for "Q and A". I don't believe, with people in very different locations, that too much productivity will be accomplished here.

my two cents.

Sim


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## caspar21 (Apr 8, 2009)

simey_binker said:


> I'm an ME, and am very interested in building a production EV from the ground up.
> Sim


i am interested to see what you mean by "from the ground up"
if you mean designing the motor, chassis etc.. then we can get help from people in this thread. i have been looking back to see the people that have offered their skills for this project. i am going to be contacting some, i think.



simey_binker said:


> I'm currently in Toronto.
> Sim


i am in muskoka, 1.5hrs from the 400/401 junction.
my skills are electronic technician/backyard mechanic. so i should be able to handle most wiring and bolt placing. but designing boards and controllers is beyond me. however.. i have this friend... lol.


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## simey_binker (May 13, 2009)

caspar21 said:


> i am in muskoka, 1.5hrs from the 400/401 junction.
> my skills are electronic technician/backyard mechanic. so i should be able to handle most wiring and bolt placing. but designing boards and controllers is beyond me. however.. i have this friend... lol.


funny thing, I was planning on saying in my last message that I was, in fact, also in Muskoka for the summer - at Ontario Pioneer Camp - staffing their Leader in Training course. but I'm moving into Toronto for september (no formal plans yet - maybe work at Hatch).

from the ground up, means, from the ground up. we'll probably implement suspension/airbags/other bits from existing vehicles at first; but myself and some others have been playing with the idea of building an electric car for production. there's a LOT of legalities to look into (we're decently comfortable with the technical issues we'll run into).

keep on working things, this'll break open soon, and when it does, it'll be fast.

Sim


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## bliksem (Aug 3, 2009)

I am in Stouffville , Ontario.
Should have my CNC router ( 8' x 4') ready at the end of the year.
Would like to help.


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## caspar21 (Apr 8, 2009)

excellent!
now we need to get back to basics.
i am going to start pm'ing people that have expressed an interest
so we can make sure we have all fields of study covered.

i still have not heard from jimp so i think its safe to say he is either unable or uninterested in running this.


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## caspar21 (Apr 8, 2009)

Morf said:


> Hi Caspar21,
> I don`t know if a genaric prototype would want a Brusa type armature or not, but when one reads about the complexity of making copper castings that would come out uncontaminated and bubble free, it seems like the expense is inevitable....
> Best Wishes,


i hear yah. we will probably do something similar is finding a popular cheap motor chassis and modify it to our purposes. all legal problems would need to be delt with.

i am expecting the outcome for this project to be a series of easily obtainable part numbers that assemble easily in a short period of time in someones garage. the product would have to be flexible for many different EV applications and controllers. i am expecting different windings to allow for a range of 10kw to a hefty 75kw.

discussion onward as usual.


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## simey_binker (May 13, 2009)

the sketchy connection to the Series of Tubes up here in Muskoka has forced me to lose a response I just wrote.

in short; if we diverge too much from the OP's topic, then we may need to start another thread. if we plan on being serious about building ANYTHING (motor or entire car) we'll need better communication for those who would like to get involved. that is, this message board is great for the wealth of knowledge it brings from people around the world, but if we'd like to actually get anything DONE, we'll need a more serious medium. for anyone organizing a posse in southern Ontario, you can contact me with simey_binker at hotmail, to which I will send my gmail address and cell number. I'll explain my background later.

the other gentleman who I've been conversing about building a car, is a mechanic in Smiths Falls, who has a garage (and plans on expanding his facilities soon).

Sim


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## simey_binker (May 13, 2009)

back to the topic at hand; I'm a mech eng, so I'm a little dodgy on the electrical side (compared to some of you geniuses). however, I've been giving BLDC (which in some ways is AC...) a lot of thought. here are my thoughts; in-wheel motor, with rare earth magnets on the rotor (outside rim), and several electromagnets on the stator hub. 

here's the question; what is that configuration you can place 4 magnets such that it increases the magnetic field on one side significantly (while reducing it on the other)? I saw it somewhere, but now I forget what it's called - and more importantly, what the configuration is.

Sim


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## Amberwolf (May 29, 2009)

Halbach Array, most likely.
________
UrSatisfaction live


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## simey_binker (May 13, 2009)

that's it champ - thanks. anyone else know if this is widely employed in the making of electric motors? I think it'd be neat to do some experimentation.

Sim


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## caspar21 (Apr 8, 2009)

an update:
we are currently looking into a project direction.
should we assemble cheaply and easily obtainable AC motor
using existing tech, or should we design a new product that is cheaply marketable?

we are looking for someone that is capable of
designing an AC controller. probably just for consulting
but possibly for a large part of the project.

please PM me or email me at [email protected] if you are capable and willing.


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## Joel (Jul 29, 2008)

this guy (user name: etischer ) made his own AC motor controller http://www.diyelectriccar.com/forums/showthread.php?t=27893 
for those old cheap Siemens AC drives that were floating around with no controllers.

His webpage his here, and he hasn't posted in this thread, so he probably doesn't know about it.


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## Dennis (Feb 25, 2008)

Industrial AC motors are cheaper than industrial DC motors and I bet they are cheaper than those AC EV motors too.

So with that said I'd start a motor rewind shop to get a feel of how to wind, count turns, do pole changes, make slot liners, apply phase separators, wind in concentric or wave winding patterns, make and insert slot wedges, pick the right insulation varnish, use a dip tank, set proper cure temperature in oven to cure varnish and do a voltage change, and EVEN FREQUENCY CHANGE of industrial motors up to say 25 HP. While it will take less copper for a 400 HZ motor for the same HP, therefore saving on weight, I am not so sure the stock iron laminates used for 60HZ motors will far too well at 400HZ. It could get hot from eddy currents. But that is for you guys to find out by actually converting a 60HZ motor to a 400HZ motor rather than listen to me babel. 

See what you can do with those motors for EV's. They may not work so well if wound for 400HZ though, but at least you have something that is already designed which all you guys have to do is modified it. It makes no sense to reinvent the wheel when it already exists and therefore can be modified. 

The industrial ac motor can have fried windings so as long as the coils are not melted you can take data of the bad motor and rewind it for 36 volts and even do a pole change. Heck, go to ebay and buy a crappy burned out seized bearings 3-phase AC motor for cheap and simply do the repairs to make the motor the way you like it.

Jim takes series wound DC motors and makes them super beast and he does not have to know all the theory. All he has to do is improve upon what has already been made which has definitely allowed his motors to survive high currents, high voltage in drag racing which a stock one would not.

The best book that really would help out is entitled: "Electric Motor Repair" by Robert Rosenberg and August Hand (ISBN 0-03-059584-3). The three phase motor section is a goldmine of information that tells you how to do pretty much anything to an AC motor whether it is speed change, frequency change or even voltage change by knowing the stock data that you gather from the ruined motor and simply apply some formulas for the changes needed.


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## caspar21 (Apr 8, 2009)

Joel
i saw eischler's blog before.. he did an amazing job.
too bad the siemens motors are so hard to get now.
if i remember correctly, they went from 800$ to over 2500$ overnight
when he completed his controller. i think that 90+mph sold it fast.

ABB looks like it might be a good place for us to get ideas. they have
a large product list and do professionally what we might be doing 
as a DIY. standard case, various options for armatures and windings, various configurations. hrmm. i wonder what their prices are like.

Dennis
thanks for the info! i got some reading to do now.
and more research...


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## vwdevotee (Mar 8, 2008)

Dennis, How much more power do you think (off hand, nothing that requires a detailed analysis) you could get out of a motor by rewinding it? Do you think it would be possible to rewind a 25HP continuous motor to something like the Tesla's 200HP peak motor? Do you think that the eddy currents in the rotor would be fatal or would the centrifugal force of turning a 3600RPM motor at 12000RPM likely just explode the rotor?


Peace!


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## Dennis (Feb 25, 2008)

> Dennis, How much more power do you think (off hand, nothing that requires a detailed analysis) you could get out of a motor by rewinding it? Do you think it would be possible to rewind a 25HP continuous motor to something like the Tesla's 200HP peak motor? Do you think that the eddy currents in the rotor would be fatal or would the centrifugal force of turning a 3600RPM motor at 12000RPM likely just explode the rotor?


It would still be 25HP continuous if 60HZ, but what matters is how much peak can you get out of it for a short duration without smoking the windings. When you rewind the motor you can upgrade the windings to class H windings and varnish to survive peak HP demands. If you could get 400 HZ which is less turns for the same HP then you can fit more windings for a 400HZ setup to get more HP out of it. It could get hot though from 400HZ due to the iron laminates being optimized for 60HZ as far as I know, but talk means nothing if I do not test it myself so I would say buy you a fried 3-phase motor for like a few dollars and just take the plunge into building it for more HP and 400HZ and see what you get. I rather not be the type to bring down such an effort with negativity. So just go for it.


All motor supplies can be bought from: http://www.shopeis.com/b2c/b2c/init.do?shop=EIS_B2C

For the new varnish I would use Dolph's CC-1105HTC.


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## unclematt (May 11, 2008)

coulombKid said:


> The Aluminum wire is in the stator so I don't see a concern on stretching. It's conductivity advantage has to do with amps per pound, not amps per circular mil. On a high tension line where weight is a concern but space isn't, by all means use aluminum. In an AC motor connection integrity is harder to maintain and reliability will suffer. Also the cube of the motor for a given horespower will grow if you use aluminum. Using aluminum will increase the size and weight of the stator laminations to attain a given flux density across the air gap. To maintain high propulsive effeciency I recommend the team stick with copper.
> As for 400 hz, probabily a good thing. Army generators supporting missle batteries used to be 400 hz because the power for the computer systems was much easier to regulate and control. Current chip sets should be able to keep up with the carrier frequency required to generate drive frequencies in the 400 Hz range. Faster motors are lighter motors. Higher drive voltages would also be a good thing. Current commercial technology uses 480 VAC a lot in the 30 hp range. A 600 VDC pack is a pain to build but insulation weighs less copper and a 480 VAC based system cuts copper weight in half. Fuses and breakers also get lighter. Any IGBT you wish to use is 600 Volt rated in its cheapest rendition now. Only the US and Japan cling to low voltage three-phase these days. The automotive standard bat pack in a decade will be 600 volts worldwide for all the reasons listed above.


 Just a thought, but on the "build your own series hybrid generator" thread, tj4fa has a couple of 400hz, aviation APU's that he has been trying to get to work in a series hybrid configuration. He describes them here:

" The alternator head I have (out of a Boeing 737) is 3ph 400hz 120/208 111A weighs 82 lbs..."

I wonder if one of these might not serve well as a lightweight frame to build this AC motor prototype on? I believe they are brushed, so some redesign and reworking of the motor would have to be done. Please contact him or check out the thread for full photos and specs.


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## vwdevotee (Mar 8, 2008)

What about using commercially available stator/rotor combinations? I've seen a couple of companies that sell them as partial motors for integration into other items like spindles or winches or whatever. I know it goes against the complete opensource/DIY concept, but it would push the hardcore engineering off to a company that specializes in that.


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## caspar21 (Apr 8, 2009)

both very good ideas.
we are meeting on Wednesday in person to discuss our game plan
and proposed end result.

if anyone has experience with AC controllers and wishes to join in then drop me a note please.


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## simey_binker (May 13, 2009)

for anyone else in southern Ontario who would like to meet with us tomorrow (wednesday, Sept 2) night, simply drop me an email at simey_binker at hotmail.

thanks for all the input.
Sim


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## caspar21 (Apr 8, 2009)

we had a great meeting while munching on Wendy's.

decided we will probably make a easy low cost syncronous wheel motor and controller.

basically a 4 motor system permanent magnet AC system, also known as a BLDC that can be used in wheel hubs or end to end turning a differential. flexibility and low cost being the key factors.

looking at 10kw per motor continuous, which would put them slightly more powerful than the siemens and more powerful than the ac55, with more flexibility for location and configuration.
with a 1:1 differential we are looking at a max vehicle speed of aprox 100 mph on a 19 inch tire.(i'll leave the math to you for now)

max kw surge will have to be determined but i am guessing around 40kw per motor, possibly higher. 

The controller will be tailored to feed the motor to these limits.

wish us luck. all donations will be appreciated


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## major (Apr 4, 2008)

caspar21 said:


> decided we will probably make a easy low cost syncronous wheel motor and controller.
> 
> wish us luck.


Hey guys,

Good luck. And how is this different from 

http://www.diyelectriccar.com/forums/showthread.php/open-source-hub-motor-wheel-motor-14185.html 

?


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## simey_binker (May 13, 2009)

probably not much different. I did a quick skim through - looks like good info.

specifically - I'm not sure where the OP for this thread got to. so myself, Casper, two others, and probably Joel at some point, will be actually building a motor/controller in southern Ontario. we'll be using this space for sharing our findings, and asking questions.

I'm sure between these two builds, we'll have a good sized pile of information to make a few articles or stickies.

Sim


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## unclematt (May 11, 2008)

simey_binker said:


> probably not much different. I did a quick skim through - looks like good info.
> 
> specifically - I'm not sure where the OP for this thread got to. so myself, Casper, two others, and probably Joel at some point, will be actually building a motor/controller in southern Ontario. we'll be using this space for sharing our findings, and asking questions.
> 
> ...


 I started that thread, and it didn't produce anything tangible. Too many people wanted to go in too many directions. Not enough cohesion within the group to overcome different design alternatives.


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## JRP3 (Mar 7, 2008)

I have to question making a wheel motor as your first motor. It's proven to be the hardest to implement well, but good luck with it in any case.


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## caspar21 (Apr 8, 2009)

JRP3 said:


> I have to question making a wheel motor as your first motor. It's proven to be the hardest to implement well, but good luck with it in any case.



the skillset we have has both aged experience and youthful innovation. i do not doubt our ability to complete the task. 

as for the other thread and differing opinions, thats too bad. fortunatly
we all put forward what we wanted and came out with a result that will fullfill all our requirements as our requirements were not conflicting excessively.

it will be a bit tough to design a wheel motor that can be setup in a "Siamese/under the hood" configuration as well. but at this point in the development phase it looks to be possible.


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## simey_binker (May 13, 2009)

thanks guys for your input. I do believe a wheel motor is difficult to build - but I find normal motors boring. and not worth investing time into. besides - I'm a mechanical guy - this is my forte to make the application work.

yeah - I noticed that in the other thread; a lot of benchracing and not a lot of progress. that's no fault of anyone - it's just because this is a world-wide forum. a lot of people with ideas and solutions, but not the ability to get together and test stuff out.

so, yes, we've assembled a crack squad of savvy motivated personnel to actually build something. we'll be taking the suggestions and ideas presented on this site, and putting it into physical form.

stay tuned, and keep the ideas coming. we'll update y'all as soon as we have some more info/progress.

Sim


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## unclematt (May 11, 2008)

You might consider more than a 3-phase motor. PML Flightlink used 18 to 20 phases in their wheel motor to achieve some pretty impressive results. You should also check out the harmonics design of Chorus Motors, and the capacitor drive design of raser technologies for some interesting ideas.


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## JRP3 (Mar 7, 2008)

PML claimed results that I'm not sure were ever proven in the real world.


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## vwdevotee (Mar 8, 2008)

That raises an interesting thought. After noodling over a phasor diagram for higher phase order systems, why don't purpose designed EV systems like the AC150, the Hughes Dolphin, the GM EV1, etc. use high number so of phases? My first thought is just to capitilize on existing motor and controller technologies, but wouldn't it greatly reduce the stress on each phase? 

Just to show my thoughts, did I miss something here: assuming a pack voltage of 340V would give an RMS potential of 240V. With an even number of phases, then the 240V would be the peak line to line voltage, which would give a line to neutral potential of 120V. Say 20 phases would then have a power of P=20*120V*I_phase. for something comparablet to the Tesla or the AC150 the I_phase would only have to be 62.5A. Compared to needing about 360A for a three phase motor of the same pack voltage and motor power the 62.4A seems highly preferable. Granted, then the controller has to be a lot more complicated to run 40 IGBTs and Vector control has to be extrapolated to an arbitrary number of phases.

Please let me know if I missed something fundamental.


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## Drew (Jul 26, 2009)

simey_binker said:


> thanks guys for your input. I do believe a wheel motor is difficult to build - but I find normal motors boring. and not worth investing time into. besides - I'm a mechanical guy - this is my forte to make the application work.
> 
> yeah - I noticed that in the other thread; a lot of benchracing and not a lot of progress. that's no fault of anyone - it's just because this is a world-wide forum. a lot of people with ideas and solutions, but not the ability to get together and test stuff out.
> 
> ...


I'm personally not a big fan of wheel motors myself, I'm not very electrically minded, but I come from a background in vehicle chassis myself, so the first things that I think when I think wheel motor are high unsprung mass, very little opportunity to cool the motor and extremely high RMS G's. Not to mention that it would have to be fully environmentally sealed, otherwise a puddle could be the end of it, which means cooling lines running to suspension components.

The thickness of the motor would also require massive compromises in suspension set up.

Finally you wouldn't be able to put much of a gearbox in there, maybe an inline planitary with a fixed ratio, but it would be a problem to manage and mean that you might have some fairly serious issues delivering peak power at 1000RPM or less as would be required by a car motor with standard sized wheels.


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## CroDriver (Jan 8, 2009)

Drew said:


> I'm personally not a big fan of wheel motors myself, I'm not very electrically minded, but I come from a background in vehicle chassis myself, so the first things that I think when I think wheel motor are high unsprung mass, very little opportunity to cool the motor and extremely high RMS G's. Not to mention that it would have to be fully environmentally sealed, otherwise a puddle could be the end of it, which means cooling lines running to suspension components.
> 
> The thickness of the motor would also require massive compromises in suspension set up.
> 
> Finally you wouldn't be able to put much of a gearbox in there, maybe an inline planitary with a fixed ratio, but it would be a problem to manage and mean that you might have some fairly serious issues delivering peak power at 1000RPM or less as would be required by a car motor with standard sized wheels.


I completely agree. Here in my neighborhood is a company that's trying to develop a small car with in-wheel motors. Each wheel would weight over 80 kgs 










They are mostly EE and don't get the disadvantages that such a system brings. I've tried to talk them out... 

In wheel motors would be great if they would be lighter. We could almost get rid of conventional brakes, we could have the perfect 4x4 system ect...


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## Drew (Jul 26, 2009)

The unsprung weight would make the ride quality abysmal, possibly even dangerous.

BTW you bought up another good point, which is that in hard application can dump upwards of 300kW from the front discs alone, resulting in instantaneous temperatures of easily 3-400 degrees on pretty much any largish production car. Even the wheel nuts can get hot enough to burn skin on contact (I know this from experience )


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## caspar21 (Apr 8, 2009)

we have considered the limitations of in wheel motors, and that is why we are planning on making it easily changed over to a stackable under hood design for the less skilled DIY'er.

as for unsprung mass, we have some alternative magnet designs and low cost composites being used to a large degree.


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## Drew (Jul 26, 2009)

Whats your target weight for each motor?

The reason I ask is because the relationship between the sprung and unsprung masses for each corner gives you a fair indication of the level of ride intrusion that you'll suffer and the relationship between spring stiffness and unsprung mass gives you the ability of the vehicle to "hold the road" so to speak.

So, large increases in unsprung mass will cause increased ride harsness AND make the car seem to float, compromising traction and road holding.

BTW another issue that wheel motors have in general is that your outer diameter is limited by either the distance between the wishbones unless you run a badly compromised suspension setup.

The only way around that is to have the motor integrated into the upright in your own design, which means integration of brake calipers and wheel bearings as well as pivot points for suspension. If you integrate the motor in this fashion then you will have to decide on a HUGE number of other variables, because you're tying down the outer pivots for wishbones if you're going to integrate them, which ties down almost all suspension characteristics, you'll have to integrate wheel bearings, which will tie down maximum wheel loadings and the brake caliper positions, which will limit pretty much everything else.

Some additional points to consider are that; 

Any increase in rim diameter will decrease road compliance increasing your RMS G's that your motors going to have to survive. 

Any significant depth to the motor (if its between the upright and the wheel, or is integrated into the upright) will move your suspension pivots outboard and compromise steering geometry badly, assuming you're using front wheel motors.

If you're planning on putting something together which assembles behind the upright and inbetween wishbones then you will also have some fairly chunky restrictions, such as the dynamic envelope of the wishbones and the position of the spring/damper.

In short I think you'll find that its extremely hard to build an electric motor which can be integrated into any existing upright and moys DIYers are going to have a hard time designing a properly functional suspension setup from first principals without prior experience.


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## unclematt (May 11, 2008)

vwdevotee said:


> That raises an interesting thought. After noodling over a phasor diagram for higher phase order systems, why don't purpose designed EV systems like the AC150, the Hughes Dolphin, the GM EV1, etc. use high number so of phases? My first thought is just to capitilize on existing motor and controller technologies, but wouldn't it greatly reduce the stress on each phase?
> 
> Just to show my thoughts, did I miss something here: assuming a pack voltage of 340V would give an RMS potential of 240V. With an even number of phases, then the 240V would be the peak line to line voltage, which would give a line to neutral potential of 120V. Say 20 phases would then have a power of P=20*120V*I_phase. for something comparablet to the Tesla or the AC150 the I_phase would only have to be 62.5A. Compared to needing about 360A for a three phase motor of the same pack voltage and motor power the 62.4A seems highly preferable. Granted, then the controller has to be a lot more complicated to run 40 IGBTs and Vector control has to be extrapolated to an arbitrary number of phases.
> 
> Please let me know if I missed something fundamental.


I am also a proponent of high phase number, even though it does require a more complicated controller. The benefits are as you state. I have read the patents associated with the PML wheel, and the Chorus motor, and that is the conclusion they came to as well. I have found a number of other patents that suggest using this idea as well. Maybe its time has come...


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## 1clue (Jul 21, 2008)

DIY AC Motor: Great!
More than 3 phases: Interesting, I have wondered about that.
DIY controller: OK, as long as somebody else does the brain work on that.
Wheel motor: Absolutely, positively no way in hell I want those, either in the wheel or in the engine compartment.

Why does everyone insist on making wheel motors? You cut out so many options and add so much weight and put it in the absolutely, positively worst place to add weight that they become useless for anything except a low speed NEV.


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## simey_binker (May 13, 2009)

1clue said:


> DIY AC Motor: Great!
> More than 3 phases: Interesting, I have wondered about that.
> DIY controller: OK, as long as somebody else does the brain work on that.
> Wheel motor: Absolutely, positively no way in hell I want those, either in the wheel or in the engine compartment.
> ...


thank you for your enthusiasm.

Sim


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## unclematt (May 11, 2008)

On the unsprung weight of wheel motors:

I have read many forum threads about this issue, including the open source wheel motor thread, and the concensus is that it isn't an issue as long as you stay within reason. It has also been the subject, in part, of a few papers on projects I have read, and even when the unsprung weight of the wheel motor design was 10 to 20 pounds heavier than stock, little problems were noted or experienced in prototype EVs. Yes, the weight of the motor is still the primary factor, so you can't just use any motor design. But if you use a high frequency motor with a high number of phases, I think it is possible to achieve a wheel motor that is powerful and meets the weight limits of the vehicle's suspension. I am also fond of the axial flux motors as well, as their size and output would lend themselves well to wheel motor designs.


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## AmpEater (Mar 10, 2008)

I have several vehicles with solid rear axles. While not optimal, it works. You don't see trucks sliding off the road when they hit a bump simply because they have more unsprung weight than absolutely necessary. It seems to me you could develop a wheel motor that ended up with less unsprung weight than a solid rear, or at least equivalent, which would therefore handle no worse than an acceptable suspension while providing numerous benefits (mostly in mechanical simplicity, redundancy, and design possibility)


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## John (Sep 11, 2007)

unclematt said:


> On the unsprung weight of wheel motors:
> 
> I have read many forum threads about this issue, including the open source wheel motor thread, and the concensus is that it isn't an issue as long as you stay within reason. It has also been the subject, in part, of a few papers on projects I have read, and even when the unsprung weight of the wheel motor design was 10 to 20 pounds heavier than stock, little problems were noted or experienced in prototype EVs. Yes, the weight of the motor is still the primary factor, so you can't just use any motor design. But if you use a high frequency motor with a high number of phases, I think it is possible to achieve a wheel motor that is powerful and meets the weight limits of the vehicle's suspension. I am also fond of the axial flux motors as well, as their size and output would lend themselves well to wheel motor designs.


For me the debate on wheel motors and unsprung weight is a contest between the high ideals of superb vehicle handling and minimum mechanical complexity and the mechanical reliability and packaging advantages that could yield. Obviously there are already a lot of vehicles in use today that already have a high unsprung weight. Anything with a live axle such as a pickup truck does. The handling of these vehicles does reflect this but doesn't render them useless or even that bad. For me the balance definitely falls in favour of superb handling as I don't see much advantage in exchanging mechanical complexity for electrical complexity and cost. For me the servicing requirements of the extra mechanical bits, is insufficient to justify what must be sacrificed to get rid of them.


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## tj4fa (May 25, 2008)

unclematt said:


> Just a thought, but on the "build your own series hybrid generator" thread, tj4fa has a couple of 400hz, aviation APU's that he has been trying to get to work in a series hybrid configuration. He describes them here:
> 
> " The alternator head I have (out of a Boeing 737) is 3ph 400hz 120/208 111A weighs 82 lbs..."
> 
> I wonder if one of these might not serve well as a lightweight frame to build this AC motor prototype on? I believe they are brushed, so some redesign and reworking of the motor would have to be done. Please contact him or check out the thread for full photos and specs.


Below is the un-brushed Aircraft Generator UncleMatt was refering to. I've heard generators could be used as motors. 

Length ~14 inches
Diameter ~ 12 inches


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## AmpEater (Mar 10, 2008)

John said:


> For me the debate on wheel motors and unsprung weight is a contest between the high ideals of superb vehicle handling and minimum mechanical complexity and the mechanical reliability and packaging advantages that could yield. Obviously there are already a lot of vehicles in use today that already have a high unsprung weight. Anything with a live axle such as a pickup truck does. The handling of these vehicles does reflect this but doesn't render them useless or even that bad. For me the balance definitely falls in favour of superb handling as I don't see much advantage in exchanging mechanical complexity for electrical complexity and cost. For me the servicing requirements of the extra mechanical bits, is insufficient to justify what must be sacrificed to get rid of them.


There are alot more possible cabin/chasis designs possible when you remove the need for transaxles/driveshaft from a central point. Plus complex mechanical systems like AWD, traction control, ABS, etc can be implemented electronically. While unsprung weight is counter to absolute performance, unnecessary weight and volume are also counter to performance per unit of energy consumed. 

It seems like anytime you can make a single part perform multiple functions, like the wheel bearings also being the motor bearings, the rim also functioning as a motor casing, etc, there would be big advantages over a similar vehicle in which these parts are redundant. But it does lead to "black box" vehicles which are impossible to repair/modify/tweak without the proprietary information owned and controlled by the manufacturer.


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## John (Sep 11, 2007)

AmpEater said:


> There are alot more possible cabin/chasis designs possible when you remove the need for transaxles/driveshaft from a central point. Plus complex mechanical systems like AWD, traction control, ABS, etc can be implemented electronically. While unsprung weight is counter to absolute performance, unnecessary weight and volume are also counter to performance per unit of energy consumed.


To gain most of these advantages would require a from the ground up vehicle redesign and if this was done most of the advantages could be realised without the penalties by mounting the motors just inboard of the suspension and connecting them to the wheels with short drive shafts. This would still be extremely complex electrically. For a conversion most of these refinements couldn't be taken advantage of.


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## caspar21 (Apr 8, 2009)

good points there drew. we are discussing different methods and designs.
pro vs con etc.


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## unclematt (May 11, 2008)

John said:


> To gain most of these advantages would require a from the ground up vehicle redesign and if this was done most of the advantages could be realised without the penalties by mounting the motors just inboard of the suspension and connecting them to the wheels with short drive shafts. This would still be extremely complex electrically. For a conversion most of these refinements couldn't be taken advantage of.


 I respectfully disagree. I think you could get away with just redesigning the attachement points from the donor car's suspension and perhaps opitimize the suspension geometry for the new system.


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## 1clue (Jul 21, 2008)

Why would I want a car that handles like a truck, and is as safe as a truck? It's still a car, and it still has to satisfy car safety standards, which are higher than truck safety standards.

The first place manufacturers go to get better handling is the wheels. They make them as light as they reasonably can. The better sports cars have rims that weigh a couple pounds, and they go through great pains to use superior materials to make the entire unsprung weight very low.

Show me a major automotive manufacturer for cars sold in the USA which supports your claims about wheel weight. There are none.

Wheel motors need to turn very slowly compared to a normal motor of similar power. They're running outside of their ideal range, which means they are heavier than they have to be, not nearly as efficient as they could be and hotter than they should be.

Putting motors near centerline and running them from drive shafts lets you have more options for gear reduction, gives you much more room that is already dedicated to power train and will be much easier to convert.

The only thing better about hub motors is they look good on paper. Are you going to cut half your car apart in order to reclaim that space you "gain" by using them? What for?


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## Drew (Jul 26, 2009)

AmpEater said:


> I have several vehicles with solid rear axles. While not optimal, it works. You don't see trucks sliding off the road when they hit a bump simply because they have more unsprung weight than absolutely necessary. It seems to me you could develop a wheel motor that ended up with less unsprung weight than a solid rear, or at least equivalent, which would therefore handle no worse than an acceptable suspension while providing numerous benefits (mostly in mechanical simplicity, redundancy, and design possibility)


The issue is also that vehicles which have live axles generally have a very high vehicle mass as well, so for instance, you could pick an F250 which has a live rear and a GVM of over 3 tons. Alternately you could pick a vehicle with a live axle and a relatively low sprung mass, such as a Mustang with something like 1.6 tons, which has the ride quality of a paint shaker. I say relatively because unless I'm designing a commercial vehicle or similar I wouldn't accept a tare mass as rediculously high as 1.6 tons, especially not for a 2 seater sports car.

Serious handling issues to result from this type of problem also come down to issues like the vehicle becoming upset over corrugations, behaving dangerously under brakes, snapping from understeer to oversteer when carrying out emergency maneuvers. The list goes on, but the bottom line is that there is a reason that unsprung mass is high on the priority list for suspension designers.

On top of all of this the other major issue still stands, which is that you would be required to set almost all suspension geometry properties for the vehicle, something which isn't possible to do without having a known CoG and target roll center locations etc etc.

This also doesn't take into account the fact that integrating this type of motor will heavily compromise steering geometry, quite likely resulting in dangerous handling.

Unfortunately complete structural redesign of a vehicles mount as proposed by Unclematt isn't really feasible either, as the structure for the entire body shell is typically designed around the specific type of suspension installed in the vehicle and the location of these mount points. In addition to this, incorporating a safe set of geometry into a vehicle which you have grafted suspension and drivetrain components in a relatively arbitrary fashion will almost certainly end badly in terms of ride and handling.

I'm not trying to be negative, I'm simply trying to point out that while it may appear to be a good solution initially, people do tend to mistake vehicle suspension systems as both simple and easy to modify or understand, but the bottom line is that it is the only element of a vehicle design that nobody has yet determined a way to accurately model using computers due to the underlying complexity of interaction of the large number of competing and interrelated factors.

In addition to all of the above nobody has yet addressed how they propose to mount a motor in a wheel which may end up driving through water, gutters, drains, whatever. I'd suggest that it would all have to be environmentally sealed and as such would require coolant to be pumped over a wishbone through flexible hosing which just adds another layer of complexity to an enormous task

Simply put, accepting 2 CV joints per side of the vehicle, which are essentially maintenance free, to move the wheel motor inboard of the suspension is no compromise at all compared to reinventing the wheel in the way that you're describing.

The benefits of integrating individual wheel motors on the sprung mass are that the suspension can do what its designed to do, which is absorb bumps, which lowers the loads on the motor, the car and the driver and passengers. It also allows much more freedom with regard to the basic layout of the motors whilst still allowing all of the benefits of individual wheel control. On top of that it allows you to be able to run cooling as a separate system which is isolated from any requirement to flex over joints. You also don't have long motor control cables or relatively exposed sensor wires running the length of moving structure.

CV joints are virtually maintenance free and do not frequently fail, but compromising your design to get rid of eight of them seems a little arbitrary.


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## 1clue (Jul 21, 2008)

Re-inventing the wheel. I love it! Did you intend the double entendre?

Absorbing bumps is only a part of what suspension does. More importantly, it _keeps the wheels on the ground!_ Doing that allows your brakes to do their job, the motor(s) to do their job, and your car to go in a straight line or around a curve as necessary.

Then, we're talking about 240v in 3 wires per wheel, flexing and being bathed in water, salt and whatever else they might find on roads in your area. Not just cooling tubes.

Nearly every other aspect of this project is very favorable to me: High frequency home-brew motors with a large phase count. Trying to re-invent the wheel is not even sort of favorable, and would completely negate my interest in the project.


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## CroDriver (Jan 8, 2009)

125 replies and what have we accomplished?

Let's make a motor and controller!

What should it be like?

My ideal AC motor-controller would look like this:

Voltage 300-400V

Power: 

150 kW continuous
250 kW peak (1 minute)

Weight:

100 kg

Cooling: 

Liquid or air

8.000-12.000 RPM

Efficiency ALWAYS north of 90% (even at low RPM)

Regen - same power as in motoring mode

Additional: 

- Integrated high power charger
- Integrated 100-230V charger
- BMS for up to 120 cells
- DC-DC converter 

I'm working on something like this with a partner... But it will take a while till the first prototype will work


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## 1clue (Jul 21, 2008)

Good grief!

What are you making, a dragster?

Chop those power and weight numbers in half, and maybe you'd get something other people might cooperate with. You could use one per wheel on your hot rod, or something.

As well, I doubt everyone will agree on the specifics of all these built-ins. I have no use for a high-power charger, and the BMS needs to be specific to your battery chemistry.

Why not have a simple system that can be expanded by adding simple components, and just try to do a good job at that? You can make your DC-DC converter, your chargers and whatever else, but those things are not hard to hook up and often the car shape or motor/battery location will dictate where they sit.

The more "integrated" we get, the fewer people will use this thing.

Liquid cooled is great. It's what I'm looking for.
Voltage, I have no problem with that but if we're each making our own we should be able to calculate different windings for different voltage requirements.

BMS: I think there are 2 ways to go about this that would work in the general sense:


A simple circuit that handles one cell, probably directly attached to the cell.
A board that handles some number of cells at a popular voltage, that is stackable for those chemistries which use smaller cells, so you hook 12 cells together on one BMS, then hook on another one for the next group, and the boards can talk to each other to maintain consistency across the whole pack.
Charger: I don't know that we can get a whole lot better than the chargers already out there. Internal to the car or external in the garage, that's just the sort of thing every owner is going to want to pick on his own.

Besides, we aren't even off the ground on a motor yet, let alone anything else. Let's let the people who know about each thing decide to make their own projects. Motors, the biggest thing is picking the configuration of the thing (poles, diameter, etc) all that. You could potentially figure for different numbers of plates, but if you're still talking induction then you gotta figure out the ladder for that. PMAC is a bit more figurable, except that you need to find magnets that work for you. By the time it gets to any particular builder's garage, all he's going to have to do is wind it according to his plan and finish it up. Winding is tedious, but not difficult if you're set up for it.


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## tj4fa (May 25, 2008)

1clue said:


> Re-inventing the wheel. I love it! Did you intend the double entendre?
> 
> Absorbing bumps is only a part of what suspension does. More importantly, it _keeps the wheels on the ground!_ Doing that allows your brakes to do their job, the motor(s) to do their job, and your car to go in a straight line or around a curve as necessary.
> 
> ...


I agree why reinvent the wheel (motor) when others are already doing that?

Here is a video of Michelin's wheel motor in action. Everytime I hear the screech of the tires cornering, I think of that Michelin guy selling more tires.

http://www.youtube.com/watch?v=i1uTR-8KarE


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## unclematt (May 11, 2008)

tj4fa said:


> I agree why reinvent the wheel (motor) when others are already doing that?
> 
> Here is a video of Michelin's wheel motor in action. Everytime I hear the screech of the tires cornering, I think of that Michelin guy selling more tires.
> 
> http://www.youtube.com/watch?v=i1uTR-8KarE


Michelin has produced exactly what proves all the wheel motor naysayers wrong. And the squealing from the tires in the video is due to being in a super light car on polished concrete. Yes, DIY'ers may not be able to replicate what Michelin has done, but it still _can be done_. Its not impossible or impractical as so many have suggested.


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## 1clue (Jul 21, 2008)

OK, let's see that same car going 55 mph and hitting washboard on the road, or a big 8" deep pot hole. On a curve.


And then a regular car going the same speed down the same road. I'm not even talking something fancy here, I'm talking a Ford Escort or similar.


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## unclematt (May 11, 2008)

Check out its specs and capabilities here

Washboards will be no problem since it has an active suspension that scans the road several hundred times a second and adjusts the suspension accordingly to provide a smooth ride over even bumpy roads.

Doesn't appear in the video that unsprung weight is much of an issue either, even though each wheel motor weighs in at 95 pounds.


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## unclematt (May 11, 2008)

1clue said:


> OK, let's see that same car going 55 mph and hitting washboard on the road, or a big 8" deep pot hole. On a curve.
> 
> 
> And then a regular car going the same speed down the same road. I'm not even talking something fancy here, I'm talking a Ford Escort or similar.


 For a demonstration of this kind of suspension check out Bose's version _here. _


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## tj4fa (May 25, 2008)

Hmmm...since you're all stuck on the wheel motor thing for now, you might as well grab a little more regen power to the pack with some regenerative shock absorbers.

http://www.gizmag.com/regeneration-no-longer-just-about-braking/10640/


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## JRP3 (Mar 7, 2008)

It looks to me as if they used a gear reduction as opposed to a hub motor. That allows them to avoid the low speed high torque issue and lets them use a smaller motor.


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## JRP3 (Mar 7, 2008)

Maybe someone can translate what this guy is saying. I picked up "wheel" 
http://www.youtube.com/watch?v=oQbuvihV29U


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## unclematt (May 11, 2008)

tj4fa said:


> Hmmm...since you're all stuck on the wheel motor thing for now, you might as well grab a little more regen power to the pack with some regenerative shock absorbers.
> 
> http://www.gizmag.com/regeneration-no-longer-just-about-braking/10640/


I'm not stuck on anything, and I have serious doubts if DIY'ers can produce something like Michelin has. But sometimes people's lack of vision and naysaying gets a little old. Nothing personal against anyone here, though, and I would be happy if this thread produced a non-wheel motor. But if the guys who are working on one come through, more power to them.


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## unclematt (May 11, 2008)

JRP3 said:


> It looks to me as if they used a gear reduction as opposed to a hub motor. That allows them to avoid the low speed high torque issue and lets them use a smaller motor.


 I agree. In the photos you can see 2 motors, one for suspension, one for moving the car.


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## tj4fa (May 25, 2008)

I really like that BOSE shock absorbers.

If a wheel motor similar to the Michelin motor is developed, the regen shock absober in the wheel can provide power back to the pack everytime each wheel hits a bump.

The output of the regen shock absobers could be sent to a capacitor bank for battery pack replenshment or directly to the motor like a shot of nitrous NOS.


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## unclematt (May 11, 2008)

tj4fa said:


> I really like that BOSE shock absorbers.
> 
> If a wheel motor similar to the Michelin motor is developed, the regen shock absober in the wheel can provide power back to the pack everytime each wheel hits a bump.
> 
> The output of the regen shock absobers could be sent to a capacitor bank for battery pack replenshment or directly to the motor like a shot of nitrous NOS.


 Now if they would just put them on a production car or sell them to the aftermarket...


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## 1clue (Jul 21, 2008)

I'm not saying that a wheel motor is impossible. I'm saying that, for the same level of technology (read: cost!) you will not have similar handling to a non-wheel-motor vehicle of the same class.

I don't care if there are reduction gears in it. I don't care if there is an active suspension. If I'm going to buy a car with active suspension, I'll do it with something that has an extremely low unsprung weight to begin with, and the car will handle like a race car, instead of like a better-than-average truck.

Look.

This thread is about _DIY'ers making a motor and controller and putting it into a converted car._ Uncle Matt, you're acknowledging that wheel motors that are light and effective are probably beyond a DIY mechanic's ability. Why are you arguing with me then? Are we talking about a pie-in-the-sky dream, or are we planning to build something?

IMO, a wheel motor requires a whole lot of time and resources I don't want to put into a conversion, because there is no benefit that I perceive, that I care to have. That I would pay a single penny for, or spend a single extra minute on.

A DIY conversion stands the best chance of being a reasonable car if the absolute minimum of things are changed. Suspension is the last thing I would tackle, because it's the most complicated thing in vehicle design.

I want a wheel motor as much as I would want a bright pink dump truck to commute with.

I'm not saying, "you can't." I'm saying, "I don't want one. At all."


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## Drew (Jul 26, 2009)

tj4fa said:


> I agree why reinvent the wheel (motor) when others are already doing that?
> 
> Here is a video of Michelin's wheel motor in action. Everytime I hear the screech of the tires cornering, I think of that Michelin guy selling more tires.
> 
> http://www.youtube.com/watch?v=i1uTR-8KarE


This looks a bit like a disaster, from what I can see the suspension appears to be running off a linear bearing, which means that its not able to roll on dynamic camber to offset the loss of static camber with body roll. I'm also a bit scepical about how that linear bearing is going to survive running on an exposed shaft like that.

Also, with the shaft configured in this way would mean a serious limit in wheel travel, as the wheel travel and support length as well as the mechanical support for the hub from the shaft and the clearance for rim flexure can't sum to more than the inner diameter of the rim, which is less than the outer, so if the rim is an 18 inch rim then the total length of all of those components can't be more than 450mm at absolute most. Subtracting 150mm for an extremely small wheel travel, then 20mm for rim dynamic clearance (also small) then maybe 25mm a side to attach the shaft to the upright then you've only got 230mm to generate a support moment that has to be passed through a rolling contact bearing on a shaft which clearly isn't well environmentally sealed.

I'm also sceptical about the systems ability to generate high enough damping forces to keep the vehicle controlled.

I'm imagining that the body roll system making the car lean into the corner would also be insanely irritating after a short period of driving the car, as well as disconcerting during any sort of evasive manouvre. The body roll would be obviously necessary to offset the total absence of ability to roll on dynamic camber when the tyre is side loaded.

Additionally the system was only demonstrated over a flat piece of poured and polished concrete, which tells us that the system isn't behaving its self properly, but they want to demo a half finished product. The reason I'm comming to that conclusion is that Michelin have their own proving ground which would be on bitumen, outdoors with great lighting and much more space to demo, but which would be uneven, which would cause issues if the control algorithms weren't up to scratch.

the gearing on the damping motor would also be a cause for concern because gear tooth lash would be a MAJOR problem with smooth or consistent damping.

Lotus, Citroen and a number of other companies have developed either semi-active or fully active suspensions before, with active ride leveling etc. but I'm only seeing disaster with this thing, not the least because Citroens semi active system was the least power hungry system that I'm aware of is supposedly around 5-7kW claimed power consumption and the lotus fully active hydraulic has been reported to be in the ballpark of 70kW in normal usage. This system I would guess would fall somewhere in between, but because its moving the car body so far and against the spring I'm going to guess that its likely to be on the high side.

I guess its an interesting concept, but at the end of the day Michelin has been showing the Tweel for about 4 or so years now and thats something which would attract a Military interest, which means basically free cash to develop it and that hasn't popped up yet so I'm not seeing this as the wave of the future either.

This is another one of those things that its a shame that they didn't go with a single concept in. The regenerative damping is interesting, and the motor sounds like its got some good specs, but the linear bearing suspension system is a disaster and trying to jam it all together like that might just kill the two good elements. But thats what you get for reinventing the wheel I guess.


EDIT: If I was going to put together a list of things that I'd want for an electric motor then my main targets for an ideal motor would be a low weight, relatively high power, stackability so that if the motor wasn't used as an individual wheel motor then a number of them could be piled up nose to tail to achieve the desired power level. 

The other thing that I've only been able to find in AC motors at the moment is a constant power output over a large rev range, which makes it ideal for operation without gearing. 

It might also be a good idea to pick a standard output shaft size and interface designed to interface with an off the shelf and relatively cheap planetary gearbox or similar for reduction to use as a direct drive motor and maybe size the output shaft diameter to a size which suits a large number of stacked motors.

If possible then it would be preferable if the motor was short, diameter wouldn't be critical as long as it wasn't over approx 500mm so that could be placed in line with a wheel center without being the lowest point of the vehicle, but a short motor would mean that you could pick a power target that would suit most users, like 25kW to give a 50kW two wheel drive or a 100kW 4 wheel drive and still stack more than one at an individual wheel station to satisfy the CroDrivers out there with outputs of 200kW or 300kW by stacking 2 or three to a wheel. This would also facilitate its use in a motorbike as a long motor is going to be hard to package in a motorbike.

The internals of these things are a bit over my head, but I'm pretty good with the vehicle mechanical side of things and so far I feel like I've been a bit negative in this thread, so I hope the above helps a bit.


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## JRP3 (Mar 7, 2008)

I wouldn't count on much, if any, regen from the suspension. I believe the BOSE system uses any regen to help power the active damping, without anything left over to go back into a battery. Certainly a heavier vehicle on a rough trail would provide more but still probably not that much.


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## 1clue (Jul 21, 2008)

Active suspension is not a replacement for a light weight wheel assembly. Especially not in an EV, where you suddenly have to supply battery power and a mechanism which can throw the entire wheel up and down several times a second.


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## Drew (Jul 26, 2009)

JRP3 said:


> I wouldn't count on much, if any, regen from the suspension. I believe the BOSE system uses any regen to help power the active damping, without anything left over to go back into a battery. Certainly a heavier vehicle on a rough trail would provide more but still probably not that much.


The demonstrated Michelin suspension system appears to lift the vehicle after it has entered the turn, which means that it will actually use a significant chunk of power to operate, as its working against the roll moment as well as the corner mass of the vehicle, it wouldn't give you anything back at all, it would simply burn power from your batteries.


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## samborambo (Aug 27, 2008)

Jimp said:


> I have been looking into motors suitable for my planned conversion for some time now. My wish list is very much like a lot of others. A 400 Hz, 25-30 HP cont., 100 - 200V, water/oil cooled, 3 phase induction motor less than 150 lbs at a reasonable price that can be purchased in 1 pc or 1K pc quantities with or without a controller. In summary, this motor does not exist. If anyone knows otherwise please speak up.
> My research shows that the big issue is not technical but financial. Those that have succeeded in making a suitable motor are only selling to OEMs, they are not even talking to us (DIYs). I am opening this thread with the intent of starting a project to develop such a motor.
> I propose that ownership will be with those that contribute, with commitment to always provide a way for the DIY to purchase a motor at a reasonable price. I am an EE and I intend to develop the required inverter and I am commitment to always provide a way for the DIY to purchase or build an inverter at a reasonable price. If you have talent (engineering, project management, prototyping, accounting or finance) and wish to be involved in this with similar commitment, please post-up and lets see where this goes.
> Please refrain from the endless discussion about the whys and hows right now. Later, after leaders have been taken ownership of the disciplines listed above, we will break into groups and set goals and begin those types of discussions. For the time being my wishlist listed above is the target and mission statement and even that is subject to later refinement.


Jimp, if you've got EE skills and are interested in a collaborative effort on inverter design, I suggest you join us on the Tumanako Project - an open source vehicle system. We're working on a set of standards for interoperability so that BMS, charger, inverter, etc can be fully compatible and may introduce market competition which is a good thing. You're not tied to developing one inverter, for instance. I'm designing one in parallel to the main development inverter but based on a different processor and power stage. The same goes for the BMS too - there's already 2 BMS designs in the development stage and the aim is to make them interchangeable.

Go and have a look at the Tumanako Project wiki and blog. There's not a lot of info posted up there at the moment but I hope to change that this week.

Sam.


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## simey_binker (May 13, 2009)

thanks guys for all your thoughts; I haven't been by here in a while.

it seems like since I was here last, there's been a lot of discussion about suspension, and the present in-wheel electric motor technology.

#1, for those making points about unsprung weight not being much of an issue, as compared to the present vehicle technology standard (with solid rear axles etc) - I believe you are correct. is there room for improvement? there sure is.

#2, for those saying the "space saved" in employing in-wheel motors are a loss because present vehicles are not set up for batteries; you are correct - but who said this was for an existing vehicle chassis meant for an ICE? if you reinvent the wheel; how difficult is it to reinvent the vehicle? (it's a rhetorical question; I know it's difficult, I'm just saying it's not much of a concern at this stage).

#3, regen suspension is not cost/design/energy/weight effective. maybe only if you're rallying 24/7. active suspension is desirable; although I do not believe we'll be looking into it yet.

#4, there are several companies with prototype in-wheel motors; but are they readily available? additionally, what would have happened to Starbucks had they accepted the fact that there was already coffee shops around?

#5, at this point; it's not a question of whether or not this is a useful endeavour. for the educational value alone, it is beneficial. we've begun planning on building an AC motor here in the Toronto area. what would be more constructive is not debating on how useless this technology is or isn't; but rather what would make it better?

---

so here are some questions:

generally, which is known as a more efficient and/or effective set up; a pancake motor (vertical plates of coil/PM) or barrel-style (horizontal hoop of coil/PM) - assuming the same outer diameter and weights. below are images of a pancake-style. barrel-style is found in CD-rom motor drives.

have you guys been able to find a proper site that discusses certain motor dimensions. for instance; gauge of wire versus amperage, thickness of coils, diameter of coils, thickness of PMs, arrangement of PMs (alternating + and -, or halbach arrangement) etc etc. I'm going to go back over all the links shared in this (and other) threads to see if I can find some concrete info.

and some pretty pictures to keep you guys happy:


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## unclematt (May 11, 2008)

Simey:
Is that an axial flux motor in your color exploded views? If so, I have also been looking at axial flux as a suitable wheel motor, but would prefer staying away from magnets on the rotor to keep the rotor as light as possble. I have been trying to figure out a way to make a light, wound rotor with enough strength to resist all the forces involved. I have also been looking for a source of carbon nanotube brushes for the slip rings/commutator, but no luck so far.


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## simey_binker (May 13, 2009)

I'll see if I can respond in a timely and cohesive manner on my iPhone.

To answer your question; yes, I suppose that is an axial flux motor. I've been coining it a pancake motor - but I suppose the word "pancake" is ambiguous. I don't quite have all the correct terms in my vocabulary.

The motor shown was quickly designed by me a few nights back. I haven't released too many detailed draws just for the sake of a little non-disclosure for intellectual property protection - although we intend to have this project as open source as we can. 

This preliminary design has an inner stator with coils, with two PM plates on either side. Heaviness to the PM plates is a potential, which will be detremental to the intertia of the wheel, along with adding unspring weight which seems to be the talk of the town these days. However, I believe we'll be able to keep the weight of these rotors under the weight of the 11" brake rotor I removed. This 18" rim is actually to scale of a rim I use on my Volvo. Will the end product be for a Volvo? Probably not, but I didn't have a smart car, rx7, echo, aveo etc etc sitting in my backyard.

Sim


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## kevin_mulder (Sep 14, 2009)

finally joined... i posted a lil about my endeavors in the chit chat. im an ee and would like to contriute. ive worked on the university solar car and got to play with the motor dyno a bit. Ive protoed many dc motor controllers, the latest for my electric motorcycle. I would really like to get into 3phase work. I can work out a the power amp section of anything like nothing. If you guys can come up with the code, i can do the rest. i actuallly just got a sample ship of 600v ibgts and 500v nmos from STmicro. I am good with gate drive techniques and strive for optimal power and signal routing to avoid ringing, shootthrough, and voltage spikes... I also have an LLC that i use for wholesale perks if that benefits any.

I am working with a friend here in lansing, MI towards devoloping our ground-up roadster. he is a CAD guy with solidworks. he has a chassis designed after a miata frame. We actually met yesterday to discuss motor options (outsourcing vs homebrew). oh-and heatpiping is definately a winner. i used it on my cycle controller and it barely gets warm after 5 mins at 60A on my modified 180v pmdc motor. i built my dad a true 1kw power inverter last year for christmas after he kept blowing commercial ones of supposed suit- for some reason he can't get an extension cord for the shop vac??? so i can handle doing a little bit of snubber calculations for the power board.

I think it may be best to build a signal level board opto-iso'ed to the driver board.

Also Im thinking you guys shouldnt worry about motor voltage or any of that, you need to decide on a form factor and then find what needs to be done to get the required power out of it. like said earlier, just rewind an existing induction motor of same form and power range. I never realized how much i was learning when i re-wound my r/c car motors as a kid. 

less turns (armature) = more RPM/volt.
look at the motor as an inductor. the less turns, the faster the current can ramp up. and also why torque falls off when the current is asked to switch too fast (high rpm). Thats how these PM axial flux motors are generating torque and continuing to very high rpm with so many poles. they are coreless so as to have little inductance, high freq and very efficient w/zero iron loss.

best bet i'd say for a motor is to rewind a basic 3ph from the scrapyard. itss easier than you think. and you dont even have to balance anything. then look at making a housing thats not iron...

hoorah second post


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## simey_binker (May 13, 2009)

excellent - thanks Kevin, and welcome to the board. your input will be greatly appreciated in here. it's too bad you can't trek up to Toronto once in a while for some hands-on work. we'll see how this all works out.

as planned, we'll be building a BLDC motor; so although it would be beneficial to learn from rewinding DC or induction motors, I'd rather test on our own apparatus. and I'd rather stay away from "guess and check"; simply rewinding a bunch of times until we find the results we like. I'd like to design for the "ideal situation", and then tune as necessary.

the plan is to build a test rig (or several) that's easily adaptable and modular in construction. from there we'll be able to make a simpler version for potential production. again, we'll see how far we can get on this one.

Sim


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## unclematt (May 11, 2008)

kevin_mulder said:


> less turns (armature) = more RPM/volt.


You say fewer turns=more RPM/volt. Along those lines, I have seen axial flux designs where the "coils" on the rotor (wound rotor of course) are not wire, but thin lengths of metal that don't even wind around the rotor. They simply serve as a conduit for electical flow in the proper relationship to the stator magnetic field (generated with coils or magnets) to produce torque. The rotor has a commutator, and that is why I have been looking for a source for carbon nanotube brushes. Recent research shows they are 10 times more effective than traditional slip ring brushes, with far less friction and arcing.


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## unclematt (May 11, 2008)

Simey:
If you are set on using perm magnets, check out this advance in manufacturing samarium cobalt magnets here.


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## Dennis (Feb 25, 2008)

> excellent - thanks Kevin, and welcome to the board. your input will be greatly appreciated in here. it's too bad you can't trek up to Toronto once in a while for some hands-on work. we'll see how this all works out.
> 
> *as planned, we'll be building a BLDC motor; so although it would be beneficial to learn from rewinding DC or induction motors, I'd rather test on our own apparatus. and I'd rather stay away from "guess and check"; simply rewinding a bunch of times until we find the results we like. I'd like to design for the "ideal situation", and then tune as necessary.
> *
> ...



Or you could look at post 88 of mine which gives the ISBN number and title of a motor repair book that takes out all the guess work when you need to rewind a motor. The book is expensive though!


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## simey_binker (May 13, 2009)

does it include proper practice for sizing/arranging the PMs? that is, we're not simply rewinding - we're designing everything from scratch for "ideal efficiency/effectiveness".

Sim


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## simey_binker (May 13, 2009)

oh yeah - I remember post 88 - that was awesome. I'm looking into the book right now.

Sim


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## unclematt (May 11, 2008)

Hey Simey,
Take a look at Kollmorgen's ServoDisc axial flux motor design here . They use an ironless design to remove enertial mass from the rotor and to remove arcing at the brushes. Read the first few pages of the pdf for more. I have a closeup photo of the rotor somewhere, but I can't seem to find it. Will post it when I do.


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## Dennis (Feb 25, 2008)

> Simey:
> Is that an axial flux motor in your color exploded views? If so, I have also been looking at axial flux as a suitable wheel motor, but would prefer staying away from magnets on the rotor to keep the rotor as light as possble. I have been trying to figure out a way to make a light, wound rotor with enough strength to resist all the forces involved. I have also been looking for a source of carbon nanotube brushes for the slip rings/commutator, but no luck so far.


If it involves slip rings or commutators then it is just going into the wrong direction for what motor they want to build. The squirrel cage rotor design should be used as is for any ac induction motor. Reliability matters.


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## samborambo (Aug 27, 2008)

unclematt said:


> You say fewer turns=more RPM/volt. Along those lines, I have seen axial flux designs where the "coils" on the rotor (wound rotor of course) are not wire, but thin lengths of metal that don't even wind around the rotor. They simply serve as a conduit for electical flow in the proper relationship to the stator magnetic field (generated with coils or magnets) to produce torque. The rotor has a commutator, and that is why I have been looking for a source for carbon nanotube brushes. Recent research shows they are 10 times more effective than traditional slip ring brushes, with far less friction and arcing.


Unclematt, if you really don't want permanent magnets on the rotor because of the higher moment of inertia, design an axial induction rotor with aluminium and laminated electrical steel. The aluminium is not a bunch of thin windings but rather a number of rings (actually shorted low resistance single windings) spaced radially around the rotor plate. Stick with a double stator construction for the highest torque/power density.


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## unclematt (May 11, 2008)

samborambo said:


> Unclematt, if you really don't want permanent magnets on the rotor because of the higher moment of inertia, design an axial induction rotor with aluminium and laminated electrical steel. The aluminium is not a bunch of thin windings but rather a number of rings (actually shorted low resistance single windings) spaced radially around the rotor plate. Stick with a double stator construction for the highest torque/power density.


Get out of my head, that is exactly what I have been considering. Have you ever heard of a commercial motor or functioning design of this type? I have also been thinking of a series connected stator and rotor and use VDC in an axial flow design. Any comments or input?


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## Dennis (Feb 25, 2008)

Sorry, but you are too late to the party. Axial flux induction motors have been patented and are actually a product available from: http://www.axcomotors.com/axial-flux_motor.html.


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## unclematt (May 11, 2008)

Dennis said:


> Sorry, but you are too late to the party. Axial flux induction motors have been patented and are actually a product available from: http://www.axcomotors.com/axial-flux_motor.html.


 Those are for industrial use and utilize a solid rotor design, I am thinking of a much lighter setup with the rotor a flattened open cage. And I am certainly not foolish enough to think I am coming up with anything new, just floating ideas and concepts of interest to myself. Right now I like the idea of an axial flow design with 2 stators/single rotor, either ac induction, or series wound VDC. The fast reaction speed, flat torque curve, high efficiency, and compact cross section make this electric motor design a winner as far as I can see.


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## simey_binker (May 13, 2009)

unclematt, your link for the Kollmorgen's ServoDisc axial flux motor is broken, but I believe you're talking about this:

http://www.electromate.com/db_support/downloads/KollmorgenNseries.pdf

which another gentleman has been calling "printed circuit motors" (because the rotor is a printed circuit).

there's been some concern about rare-earth magnets, and their dirty mining (and mostly done in China). the article about the new manufacturing strategy for rare-earth magnets sounds promising, although probably a few years off commercial availability.

unclematt, could you define "series wound VDC"?

keeping in mind, on a vehicle, the rotational inertia of the rotor will NOT matter in the least. you've got a 3000lb car strapped to these wheels, and a wheel diameter of 20 some-odd inches, that wheel isn't going to be worried about accelerating fast unless you're into drifting. the inertia of the entire vehicle will overcome whatever benefit of light rotors you have.

Sim


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## unclematt (May 11, 2008)

simey_binker said:


> unclematt, your link for the Kollmorgen's ServoDisc axial flux motor is broken, but I believe you're talking about this:
> 
> http://www.electromate.com/db_support/downloads/KollmorgenNseries.pdf
> 
> ...


I would define a series wound VDC motor as a motor with the stator and the rotor windings connected in series, and being fed variable direct current.

Its not just rotor inertia I dislike, it is PM period. I would rather build a motor without them, though I know that is not your focus.

Will post more later...


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## simey_binker (May 13, 2009)

unclematt said:


> I would define a series wound VDC motor as a motor with the stator and the rotor windings connected in series, and being fed variable direct current.
> 
> Its not just rotor inertia I dislike, it is PM period. I would rather build a motor without them, though I know that is not your focus.
> 
> Will post more later...


that's what I thought you were meaning, but then I found some other pages talking about winding it differently (really, it was unclear).

yeah, I know what you mean about PMs. we're not 100% set on a setup yet - we're still working out all the present technologies. I'd like to stay out of brush-zone, but we'll see.

Sim


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## unclematt (May 11, 2008)

simey_binker said:


> yeah, I know what you mean about PMs. we're not 100% set on a setup yet - we're still working out all the present technologies. I'd like to stay out of brush-zone, but we'll see.
> 
> Sim


With a series wound motor you aren't using a commutator, just slip rings, which increases brush life dramatically. Ironless rotors also do not cause arcing at commutators very much. I have also been looking into carbon-nanotube brushes. I read some new research about them recently that shows they are 10 times more effective and durable than common brushes, and cause much less friction as well. If you can find a source, this makes using a brushed motor more attractive from a maintenance and performance point of view.


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## ehustinx (Dec 23, 2009)

caspar21 said:


> Joel
> i saw eischler's blog before.. he did an amazing job.
> too bad the siemens motors are so hard to get now.
> if i remember correctly, they went from 800$ to over 2500$ overnight
> ...


 
Hi,

New Siemens motors of the series 1PV513X can be acquired through HEC (www.hec-drives.com). Please contact HEC for pricing.

Best regards,

Eddy Hustinx
HEC


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## caspar21 (Apr 8, 2009)

so, we still moving with this? or is the hub motor too daunting?


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