# Random motor questions (feel free to join in)



## toddshotrods (Feb 10, 2009)

I have some questions that probably don't warrant a whole thread, so I figured I would open the opportunity for everyone to learn from everyone else's questions...


Why are DC motor cases cast iron? Is it possible to build a series DC motor with an aluminum case?


----------



## Woodsmith (Jun 5, 2008)

toddshotrods said:


> Why are DC motor cases cast iron? Is it possible to build a series DC motor with an aluminum case?


I think the ferrous metal case of the motor is part of the magnetic flux path that makes the motor work efficiently.

Hence it is not a good idea to machine away too much of it when turning a motor case to clean it or make it lighter.


----------



## Tesseract (Sep 27, 2008)

Woodsmith is correct - you need the case to be made of a ferromagnetic* material because it _is_ the field of the motor. The reason is because ferromagnetic materials concentrate magnetic lines of force, which means a given number of amp-turns will produce a much stronger magnetic field compared to the same coil with a core of air, or some other material with a _permeability_ of 1 (like aluminum). Since the permeability of iron is around 5000, and the silicon steel used in transformers is closer to 40000, there is clearly a tremendous advantage in using a ferromagnetic material for the motor case, even if it is denser than aluminum (permeability of 1!).

Keep in mind that the motor case must be physically strong enough to resist the torque the motor delivers under load. Not that this is a real problem with either metal, but it might make switching over to silicon steel much less compelling because you simply might not be able to get away with 8x less material in the case that the 8x higher permeability would otherwise suggest.

Silicon steel is much more expensive than cast iron, too... but so is a Ferrari engine compared to a Toyota (both love to run at full throttle, though!...  )


----------



## toddshotrods (Feb 10, 2009)

Sweet, nice feedback! So, could an "8x less" silicon steel liner be pressed into an aluminum case, to yield the same results as its cast iron counterpart? Remember, this is theorectical and cost is not the object.


----------



## major (Apr 4, 2008)

toddshotrods said:


> So, could an "8x less" silicon steel liner be pressed into an aluminum case, to yield the same results as its cast iron counterpart?


You might be able to press it into an aluminum case, but it would not yield the same results. The flux density at saturation is about the same for silicon steel and that typically used for frames, which is steel, not cast iron. So a magnetic yoke 8 times thinner would suck real bad. 

Permeability ain't the whole story 

major


----------



## toddshotrods (Feb 10, 2009)

Awesome. I am learning. I know there is a real reason for the heavy case or frame; and I know that it's actually steel. I had to know because, with people/shops I am working with now, it wouldn't be an issue for us to do an aluminum case with a steel liner. That would include FEA, etc, to make sure it was up to the task, and precision machining to finish it. Knowing the facts, I can just concentrate on what to do inside the one I have...


----------



## Tesseract (Sep 27, 2008)

major said:


> ..The flux density at saturation is about the same for silicon steel and that typically used for frames, which is steel, not cast iron. So a magnetic yoke 8 times thinner would suck real bad.
> 
> Permeability ain't the whole story  ...


I wonder if you could expand on that some more because saturation in a transformer is disastrous, but I recall a discussion here awhile ago where you said that dc motors routinely enter deep into saturation. During such I would expect the effective inductance presented by the field to totally collapse - as it would in a transformer - and therefore ripple current to shoot up - something I haven't verified with my Rogowski probe because it is scaled to max out at 200A 

Anyway, when any magnetic material - ferrite, nickle, steel, whatever - saturates, it's permeability plummets back to ~1, which is the same as air, which means there is little difference between the material and air... This is certainly the case with a transformer - if you allow the core to saturate then unless that is the desired outcome (e.g. - like in a Royer oscillator) you might as well have not used a core at all. 

So, toddshotrods, I guess I'm joining you to hopefully learn me a little more from our resident fountain of motor wisdom


----------



## major (Apr 4, 2008)

Tesseract said:


> I wonder if you could expand on that some more


Hi Tess,

I wasn't implying you want to run into saturation, although some guys make controllers which drive the poor motor there  I was just saying that permeability of different steels does not affect the magnetic induction value at which they can operate before seeing saturation. And that is what determines the required cross section for the yoke. For a certain air gap flux value, the maximum induction (flux density) before saturation determines the cross section.

To get this flux, one needs a source, called magnetomotive force (mmf) which is amperes, commonly ampere turns (AT) is used. Then around the magnetic circuit there is a total mmf drop, so to speak, which equals the mmf source. Similar to an electric circuit having a battery voltage source and resistive elements causing a total drop equaling the source. In the magnetic circuit of the motor, the overwhelming mmf drop is the air gap. Even though the gap distance is short compared to the rest of the circuit, the permeability of air causes the reluctance of the gap to dominate. So it determines the mmf source requirements, or in the wound field motor, the AT on the poles.

With regards to the size, once you have a magnetic material for the magnetic circuit with permeability high enough to make the reluctance negligible, it is of little consequence to further increase the permeability due to the air gap. It is the flux density which determines the size.

Did that make any sense 

major


----------



## Tesseract (Sep 27, 2008)

Yep - makes sense. The air gap (between the field and the armature then the field again) dictates the AL of the field structure, just like it would in a transformer, got it, and it is mostly true (once again, from a transformer perspective) that materials with higher relative permeability often can't tolerate as many AT, so the net field strength (H) is the same, or not much different. I'm thinking, in particular, of mumetal, which was an extremely high permeability but makes a lousy electromagnet all the same.

So, if there is an air gap then there must also be a significant amount of leakage inductance... I'm sure there's a trade-off involved somewhere, but in general, you want to use the smallest air-gap you can get away without saturation on transformers/inductors that carry a significant dc current component. I imagine that the same would apply to the gap between rotor and stator in a motor - the smaller the better, no?

Oh - forgot... you make the superscript 2 by holding down the alt key while typing 0178 on the number keypad.... like so ² (or cheat and use character map in Windoze).


----------



## major (Apr 4, 2008)

Tesseract said:


> I imagine that the same would apply to the gap between rotor and stator in a motor - the smaller the better, no?


Smaller ain't always better. You got a couple of things going on with the motor. A smaller gap will reduce the reluctance for the field. But it will increase the leakage for the armature and cause some undesirable effects. You have two fields in quadrature there²

major


----------



## Jimdear2 (Oct 12, 2008)

Since you guys invited any motor question I have a couple of simple ones that have popped into my head over the last months. Appoligies if they have been answered before. I'm still learning and quite often don't recognize an answer. Or just don't know how to ask.

The barrell of the motor, made from steel or some special metal, is used to guide/contain (is that the right term) a magnetic field. Does the condition of the surface, e.g. scratches, gouges, welds used when the barrell is made from rolled flat stock and drilled holes cause problems. In other words, is it worth while to remove/polish as many of the inperfections as possible?

Is there a method to figure potential/approximate motor RPM at a specific voltage that can be based on the physical specifications of the motor that can be measured with the motor under your hand, say in a dismantelers yard.


----------



## major (Apr 4, 2008)

Jimdear2 said:


> In other words, is it worth while to remove/polish as many of the inperfections as possible?


Hi Jim,

Magnetically, not worthwhile. But you can make it as pretty as you want. And it is most often called the frame, technically the yoke. And with these larger DC motors of the fork lift variety, the frames are steel, usually from a pipe mill. On smaller motors, like cranking motors with higher volume production, the frames are made from flat stock, rolled and welded. When this is done, the weld seam is positioned relative to the poles as not to cause a magnetic interference. Cast steel is sometimes used for frames, but then has to be a little larger. Cast iron can also be used, but needs to be quite a bit larger. Frames can be constructed out of laminations. Reliance does this on their large DC motors. I have also seen them made from powdered metal. The designer just needs to know what material his manufacturing boys are going to use, then he can decide on the dimensions to get the job done.




> Is there a method to figure potential/approximate motor RPM at a specific voltage that can be based on the physical specifications of the motor that can be measured with the motor under your hand, say in a dismantelers yard.


It is called the nameplate  Without that, it is a crap shoot.

Regards,

major


----------



## toddshotrods (Feb 10, 2009)

*My second question.* This has probably been covered, but there are just so many threads in this forum that it would be a full time job to search through them, and I don't have enough time to do what's already on my list! 

*Do the siamese motors* like the drag racers are running (e.g. White Zombie Datsun) *have to be the same size motor?* If not, what would be the advantages/drawbacks to running different size motors? Of course, coming from me, this is pertaining to race-type usage; and, more specifically, doing the series/parallel split thing down the track.


----------



## major (Apr 4, 2008)

toddshotrods said:


> *Do the siamese motors* like the drag racers are running (e.g. White Zombie Datsun) *have to be the same size motor?*


I guess not.



> If not, what would be the advantages/


I can't think of any.



> drawbacks to running different size motors?


More spare parts, unproven compatibility with controllers that can do the switch, unequal current share in parallel mode may prove troublesome, and just a big unknown.

My opinions for ya,

major


----------



## Duncan (Dec 8, 2008)

Hi Everybody
I have a dumb question
I am advancing my old Hitachi forklift motor by 10 degrees

Is it OK to advance it by 100 degrees? 90 degrees + 10 degrees?

I am asking because it seems to be easier for me to effectively rotate the comm end by 90 degrees plus my 10 degree advance rather than just 10 degrees

I think it will be OK - 
I think it will reverse the direction of rotation but I can get it back by reversing the field coils

Am I barking up the wrong tree?


----------



## EVfun (Mar 14, 2010)

Duncan said:


> I am advancing my old Hitachi forklift motor by 10 degrees
> 
> Is it OK to advance it by 100 degrees? 90 degrees + 10 degrees?
> 
> ...


You got it right. There is no harm in advancing it that way.


----------



## toddshotrods (Feb 10, 2009)

Ha! I have a question about rotating stuff now! Am I correct in assuming the drive end can be rotated freely with no effect on the motor's operation and functionality? My drive end bolts on with six bolts, and I want to rotate it to make the mounting pattern for the chassis mounts work better for my application. If I just pull the bolts, spin it around, and bolt it back up, will my motor run like it did originally?


----------



## AmpEater (Mar 10, 2008)

toddshotrods said:


> Ha! I have a question about rotating stuff now! Am I correct in assuming the drive end can be rotated freely with no effect on the motor's operation and functionality? My drive end bolts on with six bolts, and I want to rotate it to make the mounting pattern for the chassis mounts work better for my application. If I just pull the bolts, spin it around, and bolt it back up, will my motor run like it did originally?


As long as you are not rotating the brushes relative to the field then you're good. Since I happen to have the same motor out in the shop I'll go look at it....

No problem. Should work fine


----------



## toddshotrods (Feb 10, 2009)

AmpEater said:


> As long as you are not rotating the brushes relative to the field then you're good. Since I happen to have the same motor out in the shop I'll go look at it....
> 
> No problem. Should work fine


Cool, thanks Amp!

Hey, one more. I want to rotate the motor so that the terminals are on the bottom (facing down). This eliminates a bunch of twists and turns (needing only one turn away from the frame rails), making for a cleaner shorter route; and it cleans up the top of my motor for design purposes. Any problems with doing this?


----------



## Duncan (Dec 8, 2008)

Hi Guys
I am new to big DC motors
I have just advanced my 48v Hitachi (100 degrees) and tested it with a rather tired 12v battery
It spins nicely but I can hear a tiny ticking noise, spinning the armature by hand I can't hear anything (lot slower)
My brushes are not bedded in
Is this slight noise normal?


----------



## major (Apr 4, 2008)

Duncan said:


> Is this slight noise normal?


It's not unheard of 

I suspect the ticking noise to come from a raised commutator segment (often called a bar). It is possible for the noise to come from elsewhere, maybe even a bearing. But most cases I've seen is the comm and brushes. 

Was this a used motor? Did it make the noise before you rotated the CEH? Does it do it both direction of rotation?

If it is in fact a raised comm bar, could be trouble. Bar to bar deviation on the comm needs to be a couple of tenths or less (that is 0.0002 inch). Get out your tape measure  This takes a machinist dial indicator to verify. 

A lot depends on a lot of things. If this high bar is modest in deviation, the noise may improve with time and maybe stoning the comm will help. Operation of the motor may be acceptable. But on the other hand, it may cause excessive arcing and heat and real short brush life.

So, to answer your question directly, no, it is not normal. And the by-the-book recommendation would be to seek a professional to examine it and turn the comm if in fact that is the problem.

Regards,

major


----------



## toddshotrods (Feb 10, 2009)

How much air does it take to cool a motor (forced air system)? The kit sold by EV Source looks like a commercial strength hair dryer type blower/motor ducted to a metal band. It appears that the band simply seals off the other ports of the Warp motor, and blows air into the one the ducting is located over. This doesn't seem like much air flow to me.

One option I looked at is using the fan wheel from a leaf blower, etc. It's a centrifugal design, like a small supercharger. I found one on Ebay, and the specs for the blower it comes from are: 483.8 cfm at the housing/310.8 cfm in the tube, 161 mph air speed, from a 2.7hp/2.0kw motor spinning up to 7500rpm.

In my design custom housing, I may or may not match the factory numbers but those specs give some clue as to the potential of the fan wheel itself. Does this even sound like it's in the ballpark for cooling a DC motor that's being pushed to the ragged edge?


----------



## Tesseract (Sep 27, 2008)

toddshotrods said:


> How much air does it take to cool a motor (forced air system)?...


Easy... sorta. Realize first that the airflow will be turbulent and inconsistent throughout the motor so there will be hotspots, and you won't be able - practically speaking - to determine where they are ahead of time. 

That said, the CFM required is (1760 * kW) / Temp Rise [in C]

E.g. - you want to limit the rise in temperature to +50C over ambient the motor is 85% efficient and the average input power is 100kW:

(1760 * (100 * 0.15)) / 50 = 528 cfm

But you have 310 cfm available, so rearrange the equation to calculate the temp rise... which will be 85C. 

The rise in this case refers to the temperature of the airflow. Remember that the motor itself has to reach a higher temperature than the airflow to actually transfer heat to said airflow!

The fan blades in a leaf blower are going to be optimized for overcoming a high pressure drop - which translates into a _faster_ stream of air, rather than _more volume_ if the output is unobstructed. Of course, cooling a motor definitely qualifies as "obstructed" so this type of fan is a good choice.

And yes, it does take a surprisingly large amount of power to move enough air to cool down a big motor, doesn't it?


----------



## JRP3 (Mar 7, 2008)

There is still an internal fan so the external fan would add additional CFM to it, so the leaf blower might be more than enough. Put it on a temperature switch so you aren't wasting power until you need the cooling.


----------



## toddshotrods (Feb 10, 2009)

Tesseract said:


> Easy... sorta... the CFM required is (1760 * kW) / Temp Rise [in C]... so this type of fan is a good choice.


Thanks, that was an awesome reply Jeff! You provided an equation for calculating the CFM, a quick lesson on the whole situation/needs, and valuable insight into the type of fan I am considering! I have some other tricks up my sleeve to complement this, so I think I should definitely be okay with a leaf blower fan.

I found a better one: 190mph/535cfm - at the end of the pipe. I'm also purchasing the plastic housings, so I can duplicate the internal shape and maintain the engineering that produced those numbers. Sweet!



Tesseract said:


> ...And yes, it does take a surprisingly large amount of power to move enough air to cool down a big motor, doesn't it?


Yes! Now, I have to find a motor to drive this beast! I considered running it off the front of the motor like an ICE supercharger would be driven, but a dedicated motor would allow me to keep it running and cooling the beast after the punishment has subsided, and greater control over wen and how much air it delivers in racing environments.

I'm actually not surprised by the power required because of my ICE raicng experience. It's common knowledge that it takes a substantial amount of engine power to drive a supercharger.


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> There is still an internal fan so the external fan would add additional CFM to it, so the leaf blower might be more than enough. Put it on a temperature switch so you aren't wasting power until you need the cooling.


Yeah, definitely need a temperature switch and/or speed control. The motor driving this thing is going to be a little monster itself and I don't want it constantly sucking power out of the pack. What I really need is a master ECU that takes information from the controller, sensors, etc, and makes all the right things happen at the right time. That's a whole 'nother can of worms though..


----------



## electromet (Oct 20, 2009)

toddshotrods said:


> What I really need is a master ECU that takes information from the controller, sensors, etc, and makes all the right things happen at the right time. That's a whole 'nother can of worms though..


Sounds like a job for Dave Koller.


----------



## JRP3 (Mar 7, 2008)

A temperature switch is really all you need. You want the motor to stay under a certain temperature, the switch turns it on till it goes below that temperature. Done. Put a manual switch bypass on it if you want to turn it on early for a turbo whine effect.


----------



## toddshotrods (Feb 10, 2009)

electromet said:


> Sounds like a job for Dave Koller.


Who's that?



JRP3 said:


> A temperature switch is really all you need. You want the motor to stay under a certain temperature, the switch turns it on till it goes below that temperature. Done. Put a manual switch bypass on it if you want to turn it on early for a turbo whine effect.


I understand I don't need it, and that the temperature switch would make it work just like a conventional automotive cooling fan - on when hot/off when not. I would just like to have more versatility. The computer-controlled option is not even on the back burner right now, just a wish. In the meantime, I may opt for a few speeds. What I am trying to prevent is tooling around at a show with the forced-air system constantly kicking in/out. If 200cfm would keep the motor comfortably in the safe zone, and be barely audible, I would prefer that to "temp up/blower screams/temp down/blower off - repeat - repeat - repeat..."


----------



## toddshotrods (Feb 10, 2009)

Tesseract said:


> ...it does take a surprisingly large amount of power to move enough air to cool down a big motor, doesn't it?


Thoughts on using a treadmill motor - like this - to power it?


----------



## Tesseract (Sep 27, 2008)

toddshotrods said:


> Thanks, that was an awesome reply Jeff!


Huh... it was pretty good, wasn't it... And I didn't even work in even a passing reference to the Soliton1 <- rectified - nor did I manage to upset anyone. Fantastic! 




toddshotrods said:


> I found a better one: 190mph/535cfm - at the end of the pipe. I'm also purchasing the plastic housings, so I can duplicate the internal shape and maintain the engineering that produced those numbers. Sweet!


The only important part of the housing is the "volute", or the chamber that the fan blades (aka - "impeller" or "propeller") reside in. The discharge tube is mostly irrelevant. 




toddshotrods said:


> I'm actually not surprised by the power required because of my ICE raicng experience. It's common knowledge that it takes a substantial amount of engine power to drive a supercharger.


Yes, and superchargers are very... loud!

Forced ventilation will only increase the amount of continuous power the motor can deliver - it will have little or no effect on the peak power.


----------



## JRP3 (Mar 7, 2008)

toddshotrods said:


> Who's that?


A member here who likes to tinker with that stuff.




> What I am trying to prevent is tooling around at a show with the forced-air system constantly kicking in/out. If 200cfm would keep the motor comfortably in the safe zone, and be barely audible, I would prefer that to "temp up/blower screams/temp down/blower off - repeat - repeat - repeat..."


The external cooling should not kick in at all while tooling or any average driving.


----------



## JRP3 (Mar 7, 2008)

I know people have used treadmill motors to power other things in EV's so I think it should work.


----------



## AmpEater (Mar 10, 2008)

toddshotrods said:


> Thoughts on using a treadmill motor - like this - to power it?


I've used one of these on a previous project. Certainly can't beat them for the money. Pretty cheaply made, the whole brush assembly was plastic.

They're not a true 2.5hp though. More like 1 continuous, 2.5 peak. Anything more than 10 amps (IIRC, it was a while ago) and the sparking got pretty bad. Probably enough for your purposes. I remember getting mine smoking more than once, but I was really pushing it


----------



## toddshotrods (Feb 10, 2009)

AmpEater said:


> I've used one of these on a previous project. Certainly can't beat them for the money. Pretty cheaply made, the whole brush assembly was plastic.
> 
> They're not a true 2.5hp though. More like 1 continuous, 2.5 peak. Anything more than 10 amps (IIRC, it was a while ago) and the sparking got pretty bad. Probably enough for your purposes. I remember getting mine smoking more than once, but I was really pushing it


Thanks a million for the feedback, I think I'll pass on that one. I need to make sure certain parts on this vehicle are very robust and this is one of the critical areas.


----------



## toddshotrods (Feb 10, 2009)

Thanks again for all the feedback guys. My forced air system made a major leap forward, from raw concept to workable idea over the last couple days. The knowledge available on this forum is incredible (or maybe a little dangerous? )!


----------



## AmpEater (Mar 10, 2008)

toddshotrods said:


> Thanks a million for the feedback, I think I'll pass on that one. I need to make sure certain parts on this vehicle are very robust and this is one of the critical areas.


They may not all be [treadmill motors] so bad....I believe that there are some more robust, high quality (and heavy) metal ones out there. A while ago surplus center was selling a truckload of the cheap rolled metal frame ones for ~$15 or $20/ea and they were all over ebay for double that. I'd hesitate to pay more than $20 for one. But again, bang for buck...you're going to have a very hard time beating that

Here's an interesting idea for you....an alternator driven "backwards" as a brushless dc motor. A PMA version of a standard delco alternator, sold commonly for wind turbines and micro-hydro applications....is a 3-phase BLDC with VERY good power/weight ratio. Already has a pulley and mounting bracket built right in. Would look right at home in an "engine" bay. You could find one that weighs less than 10 lbs that would blow a treadmill motor out of the water.


----------



## Amberwolf (May 29, 2009)

toddshotrods said:


> In the meantime, I may opt for a few speeds. What I am trying to prevent is tooling around at a show with the forced-air system constantly kicking in/out.


If you end up using a "universal" motor, which most AC-powered vacuum cleaners, drills, etc. are, you can power it with an ebike or scooter brushed motor controller running off your pack voltage, and use a thermistor-based circuit hooked up in place of it's throttle. 

The only thing you might have to do to the controller is to replace the MOSFETs and capacitors with high-voltage versions, if they are not already capable of handling your pack voltage, and changing the (probalby linear-type LM317-based) low-voltage regulator's input divider or replacing the low-voltage regulator with a DC-DC converter. 

If you end up with a brushless motor for the fan, you could do the same thing using a (much more common) brushless hub motor controller for an ebike, which are available in 100V+ models already.
________
MaryJanne


----------



## toddshotrods (Feb 10, 2009)

AmpEater said:


> ...Here's an interesting idea for you....an alternator driven "backwards" as a brushless dc motor. A PMA version of a standard delco alternator, sold commonly for wind turbines and micro-hydro applications....is a 3-phase BLDC with VERY good power/weight ratio. Already has a pulley and mounting bracket built right in. Would look right at home in an "engine" bay. You could find one that weighs less than 10 lbs that would blow a treadmill motor out of the water.


That is so tempting, but I need to stay far away from that - I'm too much of a tinkerer and would end up investing way too much time in it!  I have to find a simple DC motor that keeps my focus on the design of the forced-air system.

These things are still on Ebay. The size and proposed power levels are good for this project, but the fact that they have been listed in auctions for over a year now bothers me. 4hp and 8000rpm would be ideal though.


----------



## toddshotrods (Feb 10, 2009)

Okay, I have another question. You guys have made the point clear that forced air cooling is primarily for continuous operation and there is no real benefit for peak power - I get it.

So, since the real need for it is when the drive motor is working hardest, what are the advantages/disadvantages to driving the forced air system directly off the main motor? As I see it:



*Pros*

Less complicated setup, requiring one less motor
Amount of power required (at least in my case) to drive the blower is not an issue.
*Cons*

Pulls power away from the drive motor for cooling (though this could be negligible compared to what the electric version would pull from the pack...)
Only works when the main motor is running (can't continue cooling after the vehicle is at rest - not sure if this is even necessary)
Which way would you go if you were building something similar to what I am after - appearnace means everything, performance is crucial, practicality is an afterthought?


----------



## JRP3 (Mar 7, 2008)

Remember, you already have a good fan that runs constantly inside the motor, so you only need a little extra supplemental. However, since I know you'll insist on going overboard, why not use a pulley driven blower off the CE shaft, but use an electric clutch type pulley, like an A/C compressor uses. That way you can have it on a manual switch and a temperature switch. Set it up like a supercharger


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> Remember, you already have a good fan that runs constantly inside the motor, so you only need a little extra supplemental. However, since I know you'll insist on going overboard...


Me?! Go overboard?! 



JRP3 said:


> ...why not use a pulley driven blower off the CE shaft...Set it up like a supercharger


That's what I was referring to; sorry, I didn't make the "how" clear enough.



JRP3 said:


> ...use an electric clutch type pulley, like an A/C compressor uses. That way you can have it on a manual switch and a temperature switch...


Not to steal your idea, but I have been thinking along those lines as well. I need to do some research on electric clutch pulleys.

I had a feeling you would be in favor of this idea. Just so you know, I value your conservative approach - it lends balance to my enthusiasm. As I mentioned in the Inhaler's thread before, I like reaching for the origins of the universe first (the stars aren't far enough out there ) then settling back to what is most feasible.

I'm doing a lot of research, a lot of sketching, and too much thinking...


----------



## JRP3 (Mar 7, 2008)

I'm good with excess, as long as there is a good reason for it and it's not wasting potential motive power. I also see elegance in simplicity. Here's a nice writeup on an electric clutch setup for a regen alternator http://www.waynesev.com/ev/regeneration.html
I think it would have been better to mount the clutch on the alternator in that case instead of reversing the clutch setup.


----------



## EVfun (Mar 14, 2010)

JRP3 said:


> Remember, you already have a good fan that runs constantly inside the motor, so you only need a little extra supplemental. However, since I know you'll insist on going overboard, why not use a pulley driven blower off the CE shaft, but use an electric clutch type pulley, like an A/C compressor uses. That way you can have it on a manual switch and a temperature switch. Set it up like a supercharger


One small problem with this...

When you need the extra cooling the most little is available. Motor cooling is the most needed at low motor rpm because that is when a series wound motor will take the big amps. That has been the main reason people add a blower.


----------



## JRP3 (Mar 7, 2008)

High amps at low RPM's are usually followed quickly by higher RPM's. You can also gear the pulleys to run the fan at higher RPM's than the motor. The only thing you won't get is cooling when stopped.


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> ...You can also gear the pulleys to run the fan at higher RPM's than the motor...


That would be my approach - gear it so the forced air spools up quickly and delivers a full stream really fast. In addition to allowing me to kill the noise, the electric clutch would also offer the ability to kill the fan if the gearing would cause it to spin too fast at the motor's upper rpm range.



JRP3 said:


> ...The only thing you won't get is cooling when stopped.


That's the part I like least about running the forced-air system from the drive motor.

I'm like 50/50 on the two ideas at this point. Still exploring both avenues.


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> I'm good with excess, as long as there is a good reason for it...


There's always a good reason with this project - marketing.  That's always my first consideration with the Inhaler.


----------



## EVfun (Mar 14, 2010)

JRP3 said:


> High amps at low RPM's are usually followed quickly by higher RPM's. You can also gear the pulleys to run the fan at higher RPM's than the motor. The only thing you won't get is cooling when stopped.


The first parts to fail when stuffing 500+ amps through a motor will be the brushes and commutator assembly. Low rpm/high torque operation will really heat them up fast because these parts are not that massive. They can hang on a lot longer with a good blast of air. Keeping the cooling up while waiting at the next light is also useful for heat control.


----------



## Dalardan (Jul 4, 2008)

Here's my little question! (Slightly on the subject, though)

Just wondering, while reading those posts, would small nozzles aimed directly at the contact location of the brushes and the com bar be usefull? If powerfull enough, they could blast away the produced dust (reduce zorching) and, more important, disrupt freshly made electrical arcs? I've worked with high voltage DC electrical arcs and, once started, they can sustain themselves with really low voltage. Sometimes, to help breaking the arc, we just blew some air between the contacts while reducing the voltage.

This would require a high pressure blower to ensure enough stream from the nozzles. Maybe not worth the try?

Dalardan


----------



## toddshotrods (Feb 10, 2009)

For an electric version, would one of these 1000watt/1.4hp scooter motors be enough to turn the fan wheel? I would be running a belt or chain drive at 2.5:1 or better to get the fan up to full speed


----------



## DawidvC (Feb 14, 2010)

> Just wondering, while reading those posts, would small nozzles aimed directly at the contact location of the brushes and the com bar be usefull?


The brushes and commutator are not the only parts getting heated up, so supplying cooling air only there is a good way of cooking the armature. A high rate of flow from the brush end is the normal method of cooling, either by shaft-mounted fan or from externally powered fan.

Regards
Dawid


----------



## david85 (Nov 12, 2007)

One question bugging me is how hot can you safely run a motor? Is there a general rule to go by?


----------



## major (Apr 4, 2008)

david85 said:


> One question bugging me is how hot can you safely run a motor? Is there a general rule to go by?


Hi David,

Most of the motors use class H insulation systems for the internal parts. This means an allowable temperature of 180 degrees C. Depending on the ventilation system and duty cycle, when this 180 dC limit is reached inside the motor, the outside case temperature may exceed 100 dC by a bit. Hot enough to fry spit 

Regards,

major


----------



## DawidvC (Feb 14, 2010)

A rule of thumb wwe use for industrial motor - if you can't touch it, it is too hot. However, that does not mean the motor is damaged at that stage. We have run motors with an external temperature above 65 degrees Celsius without any ill effect. Taken in consideration that at 1700m above sea level, we actually have to derate motors due to the lessened cooling experienced here, you can easily push motors past this limit without ill effect. Running them at 100 degrees Celsius for long times though is not recommended. This may sound as if these motors cannot take a lot of punishment, but getting a motor to run at 65 degrees Celsius in Johannesburg at 1700 meters above sea-level, means pushing in excess of 150% full-load current into a motor in excess of ten minutes. Normal motor temperatures here never exceed 45 degrees Celsius at full load. These are all for ac motors, as dc motors behave a little bit different, especially sepex dc motors. I believe series dc motors can take a more extreme punishment than almost any other motor, provided their is sufficient cooling available.

All motors have a thermal constant, which is the time it take for an internal temperature rise to transmit itself from inside to outside of the frame, and this constant is the actual determinant of how much heat the motor can stand. For traction purposes, it means that this is how long you can push the maximum amps the motor will accept before failure can be expected. This is also a point where individual manufacturing practices actually start playing a role on when the motor actually start breaking. The ways of dealing with wrapping and end-turns, slot-filling and additional wrapping makes a large difference between motors. In other words, if you want to push a motor to here, you very much get what you pay for.

Dawid


----------



## major (Apr 4, 2008)

DawidvC said:


> A rule of thumb wwe use for industrial motor - if you can't touch it, it is too hot.


Hi Dawid,

I've seen that most of the industrial motors, called NEMA standard over here, are class F rated. This is 25 degrees C lower than class H. These industrial motors also use standard greased bearings. The types of DC motors used by most of these guys are basically forklift motors. These typically use class H and sealed bearings using high temp grease. These are designed to run hot, too hot to touch, when at rated temperature.

Can one of these motors be too hot (beyond the 180 dC on the insulation) when the outside case is 100 dC? You bet. But on a severe overload, you could burn insulation inside the motor and still be able to touch the outside frame. But in normal EV driving, say for an hour, it would not be uncommon for the motor frame to be too hot to touch.

Regards,

major


----------



## DawidvC (Feb 14, 2010)

Major

We run a mixed bag of ac and dc motors, class F and class H insulation on both types.That is why I said rule of thumb. But too hot to touch is stiil only in excess of 65 degrees Celsius, so there is still a lot of leeway. It would be nice if some EVers could show actual temperatures that they were running their motors at, as well as what the ambient conditions were (I'm thinking white zombie etc.). We derate motors by 20% due to altitude, and are just short of doing it due to summer ambient conditions here, which mean my choice of motor for an EV will be different to someone in say Alaska. Is there someone who is willing to compile this kind of statistic for us?

Regards 
Dawid


----------



## major (Apr 4, 2008)

DawidvC said:


> We derate motors by 20% due to altitude, and are just short of doing it due to summer ambient conditions here, which mean my choice of motor for an EV will be different to someone in say Alaska.


But your EV will have less aerodynamic drag


----------



## DawidvC (Feb 14, 2010)

Too true Major, but it doesn't help with an ICE here. Even turbos get derated.

BTW, I will be going for an overvolted motor myself, so there will be some experimentation here as well

Personally I think the derating of motors over 1000 meters of commercial motors is a little bit opportunistic, as we are running some motors at 105% without problems. Some others though .....

Dawid


----------



## david85 (Nov 12, 2007)

I measured about 45C on the exterior of my motor using an IR thermometer after a drive that saw up to 50 MPH sustained. It felt warm to the touch but not what I would consider hot.


----------



## DawidvC (Feb 14, 2010)

Thanks David85. Do you have some info on the current temperature there in Canada?


----------



## david85 (Nov 12, 2007)

DawidvC said:


> Thanks Dawid85. Do you have some info on the current temperature there in Canada?


Ambient temperature was probably around 8C for that particular drive. High humidity, if that matters.

Daytime high is usually low teens, and night time low around 5 for this time of year. my town is also close to sea level.


----------



## DawidvC (Feb 14, 2010)

I thought today's rainy 20 degrees C was cold. I hope that was Celsius not Fahrenheit.


----------



## david85 (Nov 12, 2007)

Haha, yes thats celsius.

So could anyone give me a rule of thumb as to how hot I can safely get this motor when measured from the outside case? Is 60C all I get?


----------



## major (Apr 4, 2008)

david85 said:


> So could anyone give me a rule of thumb as to how hot I can safely get this motor when measured from the outside case? Is 60C all I get?


What motor is it? Is it class H? How is it ventilated? What's the typical duty cycle?


----------



## david85 (Nov 12, 2007)

major said:


> What motor is it? Is it class H? How is it ventilated? What's the typical duty cycle?


crap....I'm not sure what you mean by duty cycle...Officially its supposed to be able to put out 20kw constant and 40 peak. I have no way to verify that for sure (yet).

I think its H class but is there a way to tell?

The motor is a TEFC unit. There is a fan on the rear that is covered by a shroud but the case is almost water tight if it wasn't for the opening for the wires. This is what the motor and controller looked like before I hacked and modified them to fit the car. (cut on of the motor feet off)


----------



## major (Apr 4, 2008)

david85 said:


> crap....I'm not sure what you mean by duty cycle...Officially its supposed to be able to put out 20kw constant and 40 peak. I have no way to verify that for sure (yet).
> 
> I think its H class but is there a way to tell?
> 
> The motor is a TEFC unit.


Hi dav,

Duty cycle. Like a drag race. Steady 60 mph. Up hill. That type of thing. 

I think I remember; this from China, right? Might be a PM motor (BLDC). In that case, it could be sensitive to heat depending on the magnet type. Class H? Isn't it on the name plate? Oh yeah, China 

Well it's hard to say. I don't suppose you can ask the guy that sold the motor to you. And I am a bit surprised if this is a BLDC it does have a thermal sensor and controller cutback on overheat. Oh yeah, China.

I guess I wouldn't worry about it until I started seeing maybe 75 to 80 degrees C on the outside of the frame.

You had controller problems with this didn't you? Good going getting over that 

Regards,

major


----------



## JRP3 (Mar 7, 2008)

Open up the motor, look for an extra bit of insulation, scrape it out, stick it in a toaster oven, see what temperature it melts or burns


----------



## toddshotrods (Feb 10, 2009)

^^^ Wise guy...


----------



## david85 (Nov 12, 2007)

LOL we wouldn't have him any other way

Not sure if there is a thermal sensor in the motor becuase I haven't opened it up. The controller has one. I think there are 5 light wires that come out of the motor to feed sensor inputs to the controller. I don't know if that is enough for hall position sensors and a temperature sensor. Dang I have a lot to learn about motors

It does have a spec plate on it but thats now hidden under the car. I seem to have misplaced my photo of that tag. I know I had one .......

And yes, it is a rare earth PM motor.

*EDIT: couldn't find that photo so I jacked the car up and crawled under to shoot this (I'm guessing that "F" on the tag identifies the insulation rating):*


----------



## major (Apr 4, 2008)

david85 said:


> *so I jacked the car up and crawled under to shoot this (I'm guessing that "F" on the tag identifies the insulation rating):*


I'll stick with my 75 degree C figure on the outside, FWIW. Don't come to me with a warranty claim 

major


----------



## david85 (Nov 12, 2007)

LOL, no worries. However if I do blow up something it only means a chance to make it better.

According to this: http://tristate.apogee.net/mnd/mfnrins.asp, the maximum temperature can be 155C, but that is likely going to be somewhere inside the motor that I cannot monitor. I agree 75C is probably a safe bet. Good to know I'm not maxed out yet.

Thanks, I think I've asked enough questions for one thread.


----------



## Amberwolf (May 29, 2009)

david85 said:


> I think there are 5 light wires that come out of the motor to feed sensor inputs to the controller. I don't know if that is enough for hall position sensors and a temperature sensor.


Generally that's only enough for power and ground for the halls, plus one hall for each of the three phases. 



> And yes, it is a rare earth PM motor.


Then your big limiting factor is probably going to be the demagnetization temperature of those, or possibly that of whatever glue they used to hold them in place (usually an epoxy of some type). If the glue comes loose, and you get a good bounce or vibration, it's possible for a magnet to end up hitting the laminations.  In hubmotors (and other BLDC motors) I've seen pics of that this happened to, that's usually very bad, though not always fatal for a motor. Depends on what happens after that.  

It's usually not nearly as bad as an exploded comm, though. 


Let's just hope the F rating wasn't actually a "failed testing" stamp. 
________
Thai property for sale


----------



## DawidvC (Feb 14, 2010)

Generally these drives have what is called a 'motor map' in the software, part of which helps to model the thermal characteristics of the motor. In purpose-built units, this would actually remove any need of temperature monitoring of the motor. Basically this would limit your motor current to a set value below the nominal current (not the absolute maximum current) when the motor is overloaded, until the internal map tells it that the motor is at a temperature that is considered safe.

Regarding your question about duty cycle, EV's do not work on the S1 continous duty cycle, so any S1-rated motor can be regarded as under-rated for EV work. Your duty-cycle rating would depend very much on the actual driving you do - do you have a lot of stop-start driving, highway driving or a mix. If you do only highway driving on a relative flat area, You would be rated S2 - short-time duty. If you do stop-start driving, short distances in a city, it may be S4 - intermittent duty with starting. Most motors (not traction) will be rated for S1. Traction motors will most likely be rated something like S4.

A motor rated S1 can actually be pushed much harder than a similar motor, but with a S4-rating. It all comes back to the motor temperature constant. If you can keep the *average* temperature below the maximum steady-state temperature that the insulation can handle, the motor should be able to handle it. It does get difficult when you start factoring in magnets as well, because that is another absolute limitation for the motor.

The nice thing about motors without magnets is that, after you burned them up, you just ask the rewinders to use the next highest temperature wire


----------



## david85 (Nov 12, 2007)

I seem to remember reading that higher temperature magnets are also available, but I have no idea what they put in mine. If I ever get another motor or rebuild this one, water cooling will probably be part of the plan.

Vibration probably won't be a concern because the motor is soft mounted in the car. However I can see that as being a problem for wheel motors if you were to hit a curb and bounce off the wheel rim or something.

Thats the one thing I do remember about temperature. Power is limited by operating temperature more than anything else (short of instantly frying a winding).

Another trade off I had to consider was operating efficiency. Other options for my voltage range simply didn't even reach the low 90s. This is supposed to be around 94~96% efficient. Eventually I will have the car put on a dyno to get a basic idea of what its putting to the ground.

I know self induction motors can reach the same efficiency levels, but I simply couldn't find any in my price range. At the end of the day I wanted to go for range and even with the problems I experienced, I ended up spending less than a comparable system made in europe or the states. Last drive passed 50 MPH so I'm still generally happy with it so far. The other short comings I find can be corrected or modified later.

When it comes to rewinding I would probably be on my own anyway. The only local shop might as well have armed guards at the door. They want nothing to do with small time hobbiests or other low priced customers.


----------



## DawidvC (Feb 14, 2010)

It is a pity about the rewinder shops. The Aussies seems to have found a couple of friendly shops around Down Under. I know a guy who might be willing and knowledgeable enough for such a job, but for you he might as well be in Oz. I hope when the time comes that you can find someone willing to help. It would actually be nice to have a couple of friendly shops available in times of need.

Good luck on the future dyno testing.

It might be a good idea to figure out how to rewind a motor though 

Regards
Dawid


----------



## toddshotrods (Feb 10, 2009)

DawidvC said:


> It is a pity about the rewinder shops. The Aussies seems to have found a couple of friendly shops around Down Under. I know a guy who might be willing and knowledgeable enough for such a job, but for you he might as well be in Oz. I hope when the time comes that you can find someone willing to help. It would actually be nice to have a couple of friendly shops available in times of need.
> 
> Good luck on the future dyno testing.
> 
> ...


I haven't really pressed the issue but have noticed that when I start discussing rewinding the coils the conversation slows or comes to a complete stop. It doesn't even seem to matter when I indicate that I am not worried about the cost - seems like something motor guys would just rather not do it. I have a long way to go before I'm ready for that, but when that day comes I have decided that I won't settle for anything less than a set of custom wound coils.


----------



## JRP3 (Mar 7, 2008)

Maybe because it's boring tedious work? At least that's what it looks like to me.


----------



## DawidvC (Feb 14, 2010)

I had a few motors rewound for work which turned out real bad, so it seems some of the reluctance might be from lack of knowledge. If we have special purpose motors that need rewinding it helps to sift between the shops to find who *really* knows their stuff - just knowing how to thread wires doesn't cut it with some motors. I had to get a saw motor rewound 3 times before I found a guy who could do it properly without causing the motor to burn when we started using it . 

BTW, the Aussie forum has some nice links to some resources regarding the winding of all sorts of motors. I will post some links next time I wander down there.

Regards
Dawid


----------



## major (Apr 4, 2008)

JRP3 said:


> Maybe because it's boring tedious work? At least that's what it looks like to me.


Hey guys,

There are many such shops. In every city. Look for EASA, Electrical Apparatus and Service Association. They rewind motors all the time. Yeah, it may not look like fun, but these guys are well paid and do it right. A lot of these shops do not do small motors, or are unwilling to take on custom jobs for EVers because it is a loser in terms of profit for them. They like to stick with what they know to be a money maker. That is large motors and NEMA standards.

Regards,

major


----------



## david85 (Nov 12, 2007)

I've already concluded that if I ever were to need my motor rewound that I would be on my own to do it myself. Having a good tech article or maybe even a how to video on YouTube could help the rest of us that don't have access to friendly shops willing to help. So far my motor seems to be doing well so I am in no rush to tear it open just yet however but long term I have a growing desire for "more".

Even if I have to do it several times to get it right, it probably would end up being cheaper than having it done out. I also couldn't easily put a price in the experience I gain in doing it myself. This is a DIY forum, after all.


----------



## major (Apr 4, 2008)

david85 said:


> I've already concluded that if I ever were to need my motor rewound that I would be on my own to do it myself.


Hi dav,

You think you'd be able to pull the PM rotor out of that thing yourself? And there is a lot of equipment and process involved with the rewinding. An oven big enough to cure it after dipping it into resin. Often times 1000 pounds of magnet wire is a minimum order. But maybe you'll need that much to get right 

If you burn the sucker up, what'd you got to lose?

major


----------



## SwampDragon (Apr 3, 2010)

Ok, I'm kinda new to all this so be gentle. Hehe. 

I've done the math with the formula: Power in Watts = ((Mass in kg) (9.8m/s²) (Velocity in m/s) (Rolling Resistance)) + ((0.6465) (Coefficient of Drag) (frontal Area in m²) (Velocity^3)) and came out to 21hp. I see come motors that have lower hp and was wondering if gearing it down will work in increase the hp at the wheel. Thanks for any help.


----------



## GerhardRP (Nov 17, 2009)

SwampDragon said:


> Ok, I'm kinda new to all this so be gentle. Hehe.
> 
> I've done the math with the formula: Power in Watts = ((Mass in kg) (9.8m/s²) (Velocity in m/s) (Rolling Resistance)) + ((0.6465) (Coefficient of Drag) (frontal Area in m²) (Velocity^3)) and came out to 21hp. I see come motors that have lower hp and was wondering if gearing it down will work in increase the hp at the wheel. Thanks for any help.


 One of the things to get your mind around is that energy [and likewise power] is one of those things that is absolutely conserved... you can change from potential to kinetic or electrical to mechanical, but each time you convert, part of it gets degraded into heat, which can't be subsequently "upconverted" into useful work.
Gearing can change the force or torque, but the power is fixed.
Gerhard


----------



## SwampDragon (Apr 3, 2010)

GerhardRP said:


> One of the things to get your mind around is that energy [and likewise power] is one of those things that is absolutely conserved... you can change from potential to kinetic or electrical to mechanical, but each time you convert, part of it gets degraded into heat, which can't be subsequently "upconverted" into useful work.
> Gearing can change the force or torque, but the power is fixed.
> Gerhard


That's what I was afraid of. So I need a motor that can do 21hp. Darn. Trying to move a 1000 lb (total weight with person) ATV just about all day at about 10mph but can do 50mph for short time. Any suggestions?


----------



## GerhardRP (Nov 17, 2009)

SwampDragon said:


> That's what I was afraid of. So I need a motor that can do 21hp. Darn. Trying to move a 1000 lb (total weight with person) ATV just about all day at about 10mph but can do 50mph for short time. Any suggestions?


You will have to be a lot more specific about your hopes. I would actually be worried because suspension and steering capable of 10 mph off road work is generally incompatible with highway use. You will have something that performs badly in both regimes if you make something that sort of works in both. Put in the back of your truck for the highway run.
Gerhard


----------



## SwampDragon (Apr 3, 2010)

GerhardRP said:


> You will have to be a lot more specific about your hopes. I would actually be worried because suspension and steering capable of 10 mph off road work is generally incompatible with highway use. You will have something that performs badly in both regimes if you make something that sort of works in both. Put in the back of your truck for the highway run.
> Gerhard


It would all be off road, just sometimes it gets a lil speedy on trails. The steering and suspension we can work out. Just the motor specs is what i'm trying to figure. Torque I figured about 150-200 ft-lbs.


----------



## david85 (Nov 12, 2007)

major said:


> Hi dav,
> 
> You think you'd be able to pull the PM rotor out of that thing yourself? And there is a lot of equipment and process involved with the rewinding. An oven big enough to cure it after dipping it into resin. Often times 1000 pounds of magnet wire is a minimum order. But maybe you'll need that much to get right
> 
> ...


Thats basically my line of thinking although I have a little more faith in my abilities than you do. I have no formal training in ICE or automatic transmission overhaul either (among a long list of other skills) and I get that done in our shop too.

Minimum order policies never got in my way either


----------



## toddshotrods (Feb 10, 2009)

david85 said:


> Thats basically my line of thinking although I have a little more faith in my abilities than you do. I have no formal training in ICE or automatic transmission overhaul either (among a long list of other skills) and I get that done in our shop too.
> 
> Minimum order policies never got in my way either


I was just talking to the engineer/machinist who's cutting my parts about this today. There is such a huge gap between the thought processes of the EV community and the hot community. Hot rodding was born from a bunch of guys trying to go faster and faster. Eventually this led them inside the engines, and companies (some that still thrive today) were born to serve the ever-increasing need. Before drag racing turned into a who-can-spend-the-most-money game, that's how we won. You had an idea, tore stuff apart, modified it, and tested it. Sometimes you go faster, sometimes you don't. Sometimes parts end up in the junk pile, but the knowledge usually always leads to a better/faster effort down the road.

Two things rule the EV world: If it isn't cheap, it isn't done. That's because most EVs are built with the idea of saving, if only to recoup some of the initial investment. Racing is done for the thrill. The only way it isn't doen is if it isn't safe, or won't work. Secondly, the black art of electric motors seems to have people paralyzed. There are so many different motors, controllers, and battery setups, that development of proven tactics is slow.

The only remedy is to get our hands dirty and mess with stuff! Go for it! The only reason I may pay someone to wind mine is time - I just don't have enough to do everything I need to do... But as much as I can find people to help me experiment I am going to do it. Broken parts are the evidence of having the courage to try...


----------



## EVfun (Mar 14, 2010)

SwampDragon said:


> That's what I was afraid of. So I need a motor that can do 21hp. Darn. Trying to move a 1000 lb (total weight with person) ATV just about all day at about 10mph but can do 50mph for short time. Any suggestions?


Just a second, I'm confused. You don't need a motor rated at 21hp if that is not a continuous power requirement. Traditional electric motor ratings are continuous power 24/7 with no additional cooling (other than the internal fan, if present.) You can exceed the nameplate rating for a while.

Horsepower = volts * amps * efficiency (percentage expressed in decimal form) A 450 amp Altrax controller with a 72 volt pack will get you a peak power of around 32hp. You would want a series wound motor (series wound for low end torque) rated at about 12hp. It can be overpowered to make 3 times that for short periods of time could make 21hp for 15 to 30 minutes before temperature became an issue (forcing you to back down the power.)


----------



## Duncan (Dec 8, 2008)

Hi Guys
I thought I should update on the ticking noise I reported a couple of weeks ago

I did the sandpaper on the commutator to bed the brushes in
Measured the commutator
No visible deflection on my 0.02mm clock

I measured the comm using one of the brushes

It still ticks - but
I doesn't tick when running (not sure of speed 12v unloaded on a 48v motor)
Or when I turn it manually

But it does very softly when I cut the power and let it spin down 

I have decided that it is probably my paranoia I am hearing and I will build my car and test it that way

I hope to get the chassis started next week


----------



## SwampDragon (Apr 3, 2010)

EVfun said:


> Just a second, I'm confused. You don't need a motor rated at 21hp if that is not a continuous power requirement. Traditional electric motor ratings are continuous power 24/7 with no additional cooling (other than the internal fan, if present.) You can exceed the nameplate rating for a while.
> 
> Horsepower = volts * amps * efficiency (percentage expressed in decimal form) A 450 amp Altrax controller with a 72 volt pack will get you a peak power of around 32hp. You would want a series wound motor (series wound for low end torque) rated at about 12hp. It can be overpowered to make 3 times that for short periods of time could make 21hp for 15 to 30 minutes before temperature became an issue (forcing you to back down the power.)


Ok, that helps a bit. Guess I have more research to do.


----------



## SwampDragon (Apr 3, 2010)

EVfun said:


> ... A 450 amp Altrax controller with a 72 volt pack will get you a peak power of around 32hp...


Ok, what kind of battery pack am I looking at? Just 6 x 12 v and the controller will just pull the amps or what. Sorry for the ignorance. Just kinda ify on the batteries.


----------



## EVfun (Mar 14, 2010)

The size (amp hours, that pretty much means weight with lead acid batteries) of the pack will determine the range. If the chosen pack was to small it would have an issue with dishing out 450 amps, but even 6 marine group 27 batteries would provide that power. That would be a pretty small pack so the range wouldn't be great.

I don't know how to estimate the pack size needed for a given range, since you are not doing a common street vehicle.


----------



## SwampDragon (Apr 3, 2010)

EVfun said:


> The size (amp hours, that pretty much means weight with lead acid batteries) of the pack will determine the range. If the chosen pack was to small it would have an issue with dishing out 450 amps, but even 6 marine group 27 batteries would provide that power. That would be a pretty small pack so the range wouldn't be great.
> 
> I don't know how to estimate the pack size needed for a given range, since you are not doing a common street vehicle.


I would say about 50 miles would be my desired range at least. Below is what I'm trying to make.

http://www.electricmotorsport.com/store/ems_electric_ATEV.php


----------



## jlgh (Mar 6, 2010)

*NEMA types*

I'm trying to understand AC Induction motors used in EVs and could do with some help...

NEMA categorise AC Induction motors as type A, B, C or D in terms of torque/speed (see for example http://www.reliance.com/mtr/b7087_5/b7087_5_7.htm)

Can anyone tell me:



Which type (A, B, C or D) is commonly used in EVs
Are all EV drive controllers for AC motors variable frequency?
Can you point me at a good explanation of the term "vector control" as it applies to AC controllers?
Many thanks


----------



## zwmaster (Nov 23, 2009)

*Re: NEMA types*



jlgh said:


> I'm trying ...
> 3. Can you point me at a good explanation of the term "vector control" as it applies to AC controllers?


 
Could be a start:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=RDDSCACIMVC
RefDesign1
RefDesign2

http://focus.ti.com/docs/solution/folders/print/195.html
Theory
look at aplication notes.


----------



## jlgh (Mar 6, 2010)

That's great - many thanks


----------



## toddshotrods (Feb 10, 2009)

I have some questions about the capability of a SepEx motor I just purchased. It is:

D&D ES-71G-52 (SepEx)
Class H insulation
24-48 volts
I think 6.7 diamter and 11" long case
Has aluminum drive end cap and .875" shaft w/.1875 keyway
CONTINUOUS RATING:

4200 rpm
2.8 ft.lbs. torque
45 amps armature
9.5 amps field
2.3 hp
PEAK RATING:

3100 rpm
14.3 ft.lbs. torque
350 amps armature
20 amps field
8.5 hp

Is this motor strong enough to power a 300lb motorcycle? It's just a cruiser, no performance/racing plans.
Would it at least be able to do highway speeds? (65mph)
Can the voltage be bumped up to 72 volts without killing it? I currently have a similarly-sized GE series motor that is going in the bike that was rated for 48 volts. I planned to advance the timing and run it at 72, can anything like this be done with SepEx?
Thanks for any help. If it has the same capability as the GE I _might_ prefer to have it in the bike over the series motor to have regen. I'm not really sure which motor I want where until I get the D&D here (Friday) and get some more information about what it can do.


----------



## Jimdear2 (Oct 12, 2008)

I purched the same motor as Toddshotrods and want to piggyback my question onto his question.

I bought the motor to run a mower deck, I wanted sepex because this is a belt drive deck and I dont want an exploded motor when (not if) the belt breaks.

I want to run the motor with 24 volts (not a requirement, just convienient) at a specific RPM. 

I berleive I'm going to need to run the motor around 3000 rpm to get the blade speed I need.

My question is can I use a fixed field and armature current/voltages (TBD) with just an ON/OFF (with correct safeties of course). Or would it be better in the long run to get the Alltrax DCX4830 sepex controller that will be programmed for this motor.

Any Suggestions??????

Jim


----------



## JRP3 (Mar 7, 2008)

toddshotrods said:


> Can the voltage be bumped up to 72 volts without killing it?


Should be fine. You might find more info here http://www.ddmotorsystems.com/ElectricMotorcycles.php


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> Should be fine. You might find more info here http://www.ddmotorsystems.com/ElectricMotorcycles.php


Thanks, I looked their site when I was trying to make a decision on whether to but the motor. I gave up, because it's not very user friendly. It seems like it's more of a lure to get you to contact a friendly sales person.


----------



## JRP3 (Mar 7, 2008)

Yeah their site is terrible but you might try shooting them an email for more info. You might check the evalbum for other D&D users. Not directly related to anything but I did find this interesting mounting chioce


----------



## toddshotrods (Feb 10, 2009)

Wow, that is interesting! I think it was Jim that posted a link to a surplus site in Woody's EV thread, with gear drives like that. I looked, was tempted, then closed that tab (without saving the link) before I bought something!


----------



## Jimdear2 (Oct 12, 2008)

Toddshotrods,

I was looking around and found that the matching Alltrax DCX sepex controller that can be programmed with the field map for this motor is limited to 24 to 48 volts. They have them in versions from 300 to 600 peak amps.

If you can find a sepex controller that will go to 72 or greater volts and can be programmed to with the field map for this motor please let me know.

Jim


----------



## JRP3 (Mar 7, 2008)

Sevcon and Kelly both have Sepex controllers that have been used with D&D motors at 72 volts.


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> Sevcon and Kelly both have Sepex controllers that have been used with D&D motors at 72 volts.


I kind of have my sights set on the Kelly. I told Carl that there would probably be people coming to him for controllers as a few of us had our eye on the motors, then I realized that Alltrax doesn't have a 72 volts option for that motor. I hadn't checked into it, but figured since the company actually communicates with controller manufacturers they could get a field map for it.

Since the word on the street is Kelly controllers don't seem to crank out the advertised amps, I was thinking about a 600 or 800 amp controller, with regen of course. Carl could still make few bucks off me though if I want to get the vehicle rolling on a budget. The Alltrax controllers are cheap enough to buy a small one, and keep it for a back up after getting a new Kelly later. 

I looked at the bikes in the album. Most of them have more powerful versions of this size D&D motor. There was one little ex-race bike that seemed close. He was running cheap lead, 300 amps, and said it performed decent. It was only 210lbs though.


----------



## Jimdear2 (Oct 12, 2008)

Thanks for the information.

I have a freind who had a bad experiance with Sevcon (everything is money money money with them) so I'll have to look there with caution. 

I hear Kelly is supposed to be "Fixing" their bad reputation. I think I'll wait a while and see. 

If I found a good 72 volt set up, that motor would end up in a bike. 

I guess it will be a visit to Carl though for a mapped 300 amp DCX and just set up a complete controller, contactor, fuse and battery set up on the mower deck with a remote KSI switch and throttle pot on the tractor.


----------



## toddshotrods (Feb 10, 2009)

Jimdear2 said:


> ...I hear Kelly is supposed to be "Fixing" their bad reputation. I think I'll wait a while and see...


Though most of it seems to be due to misleading claims about the amperage of the controllers, it is also a person's responsibility to do some research and be an informed buyer. When you look at the specs, the continuous current available is often significantly less than what's advertised.

The 800 amp model I'm eyeing for this motor is a one minute rating. The continuous rating is 320 amps. I am also planning to run one of their small series controllers on the field of my big GE SepEx in the Inhaler, and had to chose a 100amp controller to get a high enough (60amp) continuous rating to guarantee 50 amps would go to the field.

I've just learned over the years never to trust the first information I get, blindly. A little research goes a long way, and a lot of research usually produces good results.


----------



## major (Apr 4, 2008)

toddshotrods said:


> The 800 amp model I'm eyeing for this motor is a one minute rating. The continuous rating is 320 amps. I am also planning to run one of their small series controllers on the field of my big GE SepEx in the Inhaler, and had to chose a 100amp controller to get a high enough (60amp) continuous rating to guarantee 50 amps would go to the field.


Hey Todd,

Looks like that model will power the field itself. But I am real skeptical about the ratings. 800A for 1 minute and 320A continuous is in Zilla territory. And that thing isn't liquid cooled; doesn't appear even to have a decent heat sink. However it might power your rod around at parking lot speeds.

Regards,

major


----------



## toddshotrods (Feb 10, 2009)

major said:


> Hey Todd,
> 
> Looks like that model will power the field itself. But I am real skeptical about the ratings. 800A for 1 minute and 320A continuous is in Zilla territory. And that thing isn't liquid cooled; doesn't appear even to have a decent heat sink. However it might power your rod around at parking lot speeds.
> 
> ...


This is for a different motor, in a different project, Major. No performance goals this time. It's a little D&D SepEx motor I picked up. Jim has one too. I am actually counting on the 800/320 numbers to be "optimistic" to match the proper controller to the motor.  D&D provides field maps for their motors, so this one can run a regular SepEx controller that is programmed for it.

The 11" GE in the Inhaler project will still be running a series controller on the arm, and another small Kelly (100amp) series controller to manually regulate the current going to the field - for parking lot/initial testing stuff. Unless I learn something in that process, I am still plannning on a series rewind for the big guy.


----------



## major (Apr 4, 2008)

toddshotrods said:


> I hadn't checked into it, but figured since the company actually communicates with controller manufacturers they could get a field map for it.


Hi Todd and others,

I also bought one of these motors. I just ran the sat curve on it. This should be enough to set up the controller.

Regards,

major


----------



## toddshotrods (Feb 10, 2009)

major said:


> Hi Todd and others,
> 
> I also bought one of these motors. I just ran the sat curve on it. This should be enough to set up the controller.
> 
> ...


When I emailed Kelly about programming a controller for my big GE with the sat curve from the Larger SepEx thread they said it wasn't enough information. Not really an issue with the little D&D though because D&D will give controller manufacturers the field map.

{{{Evil grin}}}
Since you have one of these motors Major, what's it capable of? Do you think it can it handle 72 volts? How much current? How much weight can it get moving and push around, at say neighborhood speeds (25-35mph)?

I don't know it you saw them, but Jim also had some questions back on page 10.


----------



## major (Apr 4, 2008)

Jimdear2 said:


> I purched the same motor as Toddshotrods and want to piggyback my question onto his question.
> 
> I bought the motor to run a mower deck, I wanted sepex because this is a belt drive deck and I dont want an exploded motor when (not if) the belt breaks.
> 
> ...


Hi Jim,

I was out on the coast for a bike race. http://www.diyelectriccar.com/forums/showthread.php/ttxgp-race-infineon-45085.html Gone for a week.

As you can see from post #111, I bought one of these motors. It was waiting for me when I returned home. I ran it for like an hour no load before I took that sat curve. It is totally enclosed. So it actually got pretty hot. That was at 7.5V on the armature and like 3 or 4 amps on the field. But that is the way with totally enclosed motors. Heat in them may not be that much different between no load and at rated load. Not too worried and tend to trust the rating.

That said, totally enclosed motors will run at higher power at increased voltage, but the HP rating (continuous) will not change that much. It always boils down to the loses and surface area. So regardless of the voltage (speed), the nameplate HP rating is all you can expect if running for more than 30 minutes or so.

Now then, blade motors are a bitch. Like a fan load with a bunch of sh!t thrown in to increase density of medium being flung around. I think this particular motor might do well for the right size deck. It does have a thermal sensor. I'd figure out how to use it  

Anytime you use a series motor with a belt, better have a speed sensor to shut it down if the belt breaks. I guess it would do o.k. for a direct blade drive because the blade always presents a fan load. The SepEx seems like a good choice for blades, belt or direct. If your voltage (and field current) is proper, it should do fine with contactor only (and fuse, of course).

This motor? My guess is maybe a 30/32 inch blade. Twin 24s, ??? It is a nice little motor. Looks like a short stack golf cart size. Keep it within the nameplate rating, and you should be alright. Occasional overload will be tolerated well, better than a PM motor.

I got one for yard tractor propulsion or go kart or maybe light 2 wheeler. Not sure, but price was right.

Regards,

major


----------



## Jimdear2 (Oct 12, 2008)

Major,

Thanks for the information. 

I'm going to try to run a deck that was originally mounted on an old Bolens tractor that had a 12 HP ice in it. There is a horizontal drive shaft to a 90 degree box and then belt to 3 blades. I think the deck is around 40 inches.

I want to run 24 volts, two big 12 volt deep cycle. Just battey cost deciding voltage there. I had someone suggest that I put 24 volts to the field then 24 to the armature and see what happens. Looking at your field map it looks like I should be using only 12 volts to the field and 24 to the armature. Is that right? I am totally ignorant (but learning, "Very" slowly cause I am an old dog) about electric motors.

Maybe to be safe I should get the Alltrax. Well if I "Blow It Up" learning, it wont be too expensive a lesson

I was pleased when I saw the 4 pole hall effect sender on the motor That thing (if I remember right) costs about a third of what we paid for the motor.

On another note Thanks for the link to the bike race. I started riding when I was 13, my first major job after the Army was service manager at a Honda store. I Love Bikes, just can't ride anymore. My wife had a Suzuki water buffalo when we met. She ported it herself to match the factory racer. I did a bunch of enduros, scrambles, some trials, a bit of sidecar on pavement and a lot of sidecar on Ice. (Lake St. Clair). Love the fact that there are high end EV pavement racers.

I have another motor question. I'm building (along with another person) a garden tractor super modified class pulling tractor. We have a 13 inch GE, we had the fiberglass brush carrier ring modified so we can dial in the advance we want up to +/-10 degrees from neutral. The question is, since we plan eventually to go up to 300+ volts what would be a good paint on or glue on insulator? We are getting pretty close, say 1/8 of an inch between the brush carrier and the CE bell.


----------



## Amberwolf (May 29, 2009)

Jimdear2 said:


> The question is, since we plan eventually to go up to 300+ volts what would be a good paint on or glue on insulator? We are getting pretty close, say 1/8 of an inch between the brush carrier and the CE bell.


I think they still make "InsulVolt", a spray-on lacquer insulator. My can is so old it doesn't spray and has to be painted on with a brush....

Good up to 1500V, I think.

http://www.endless-sphere.com/forums/download/file.php?id=37918
http://www.endless-sphere.com/forums/download/file.php?id=37919
http://www.endless-sphere.com/forums/download/file.php?id=37916
http://www.endless-sphere.com/forums/download/file.php?id=37917

I guess they still make a variation on it:
http://www.gcelectronics.com/order/catdisplay.asp?CatID=3

Orderable here:
http://www.action-electronics.com/gcelect.htm
and there is something called "Insulating Coating is like "Liquid Tape" that does not peel off." that sounds interesting.


----------



## toddshotrods (Feb 10, 2009)

Jimdear2 said:


> ...I Love Bikes, just can't ride anymore. My wife had a Suzuki water buffalo when we met. She ported it herself to match the factory racer...


I rode Kaw triples, and had a friend who had a water buffalo. I can't wait to get my e-bike done, it should be a unique experience.




major said:


> ...It is totally enclosed...


I thought so, from looking at the one pic that was in the auction. What's the point of an enclosed motor - protection from the environment it's designed to operate in?

Is it worth it to cut ports and do a forced-air cooling system, or better to leave it alone?




major said:


> ...I got one for yard tractor propulsion or go kart or maybe light 2 wheeler. Not sure, but price was right....major


Ditto. I didn't need it, definitely didn't need another project, but the price made it irresitible.


----------



## major (Apr 4, 2008)

toddshotrods said:


> Is it worth it to cut ports and do a forced-air cooling system, or better to leave it alone?


I guess it depends on your application and duty cycle. If you need power in excess of the nameplate for long durations, yeah, ventilation is a good idea, as long as you can keep the air pretty clean. How to accomplish the ventilation depends on your set-up. If you're running a pulley on the shaft, you might consider a fan on the pulley to pull air thru the motor. This would mean milling slots in the DEH face and also the CEH.

Putting a fan inside the motor is likely not an option. Simply putting holes in the aluminum end heads won't help much. An external blower (forced air) is always an option which could work very well. You have to get the air in one end and out the opposite end of the motor.

I guess the best option is to use the motor within its present capabilities. Totally enclosed motors are nice where you have contamination worries. But TE motors carry significantly lower continuous power ratings than ventilated motors. Forcing air over the outside of the motor leaving it TE makes it TEFC (Totally Enclosed Fan Cooled). This will help, but not nearly as much as forcing air thru the motor.

I have not popped open this motor. From the size and weight of it, I suspect it has a short core and small comm and brushes. It appears nicely built for what it is. Just don't expect too much from it. It does have what I believe to be a thermal sensor. Figure out how to use it (and let me know ;-)).

Regards,

major


----------



## toddshotrods (Feb 10, 2009)

Thanks Major. You're simply invaluable!  I don't plan on pushing the little guy too hard, I just wanted to understand what it is, and why it's that way, a little better so I could use it wisely. I may keep it buttoned up (no external cooling) and just try to monitor the temperature closely. I'll see if I can get any info on the thermal sensor.

FedEx truck is supposed to deliver it today!


----------



## toddshotrods (Feb 10, 2009)

Motor came today. It's a small little bugger, more so than I expected.









So, which wires are for the thermal sensor, and what are the others for?


----------



## major (Apr 4, 2008)

toddshotrods said:


> So, which wires are for the thermal sensor, and what are the others for?


The 3 wire pigtail is the speed sensor. I think the 2 wire pigtail is a thermal sensor, but not certain. 

major


----------



## toddshotrods (Feb 10, 2009)

major said:


> The 3 wire pigtail is the speed sensor. I think the 2 wire pigtail is a thermal sensor, but not certain.
> 
> major


I emailed D&D to see if they will provide specific info, hopefully inlcuding what type of electronic signals they send. Probably won't hear back until next week, since it's the weekend.

Really seems like a neat little motor. Seems like an incredible deal too.


----------



## Rodster (Apr 28, 2010)

major said:


> Hi Todd and others,
> 
> I also bought one of these motors. I just ran the sat curve on it. This should be enough to set up the controller.
> 
> ...


I'm curious how one would use the curve to set up the field map? Specifically field ramp settings. If your fld map start is 3 and max is 28 how does one determine the ramp to the midpoint?


----------



## major (Apr 4, 2008)

Rodster said:


> I'm curious how one would use the curve to set up the field map? Specifically field ramp settings. If your fld map start is 3 and max is 28 how does one determine the ramp to the midpoint?


Sorry Rodster,

I missed this post of yours. I got busy with the electric MC race. This refers back to the curve I took and posted (post #111).

First, that plot is not a field map. It is a no-load magnetization curve. It plots the armature generated voltage versus field current. It is useful to program a field map into the SepEx controller. The _field map_ is actually the process by which the controller determines the proper field current dependent on the armature current.

Different brands of controllers use different parameter settings to input this data. I have done this with the Curtis and Sevcon SepEx controllers. Those two are different and so I imagine other brands would also be different. The no-load magnetization curve of the particular motor does not change. But this magnetization curve is bound to be different with different motor designs. So the field map parameter settings will be peculiar to the particular motor and the brand of controller used.

The primary attribute shown by the magnetization curve which is of importance in developing the field map is the field strength or amps at which saturation occurs. Often called the knee of the curve. This curve has a steep slope up to about 5 amps. This is pre-saturation (referred to as the air gap line). And after 10 amps has a much reduced slope indicating the core is into a state of saturation. 

It is best to have the motor supplier give the motor data to the controller supplier and have them set it up properly. Or get an applications engineer in to do it for you. But if you're left to your own devices, you can use this information to make some intelligent guesses as to how to program the controller. 

I will attempt to do this with that D&D motor and Sevcon SepEx in the near future. I think I have found a programmer to borrow. If I am smart enough to do it (or remember how I did it like 5 years ago), I'll post it up for your amusement 

Regards,

major


----------



## Rodster (Apr 28, 2010)

Thanks Major. I used some estimation and graphing to develop a field map for my motor. It's very similar to the D+D one you have there. I've been using my new settings programmed into the curtis controller and I believe it's heads and tails better than the sloppy generic settings that came on the cart. 

Your curve helped me determine that the field current was too high on the generic field map. The motor runs better and uses far less battery power with similar top speed, torque and acceleration in comparison to the generic parameters.


----------



## major (Apr 4, 2008)

Rodster said:


> Thanks Major. I used some estimation and graphing to develop a field map for my motor. It's very similar to the D+D one you have there. I've been using my new settings programmed into the curtis controller and I believe it's heads and tails better than the sloppy generic settings that came on the cart.
> 
> Your curve helped me determine that the field current was too high on the generic field map. The motor runs better and uses far less battery power with similar top speed, torque and acceleration in comparison to the generic parameters.


Thanks for the pat on the back Rod. Glad it helped. But I also appreciate the post which tells me my advice didn't work. I hate hearing nothing. But am used to it.

Are you in the garage or EValbum?


----------



## octagondd (Jan 27, 2010)

Quick question, How much space should I have between the drive shaft and the motor for wiggle room. I thought an Impulse 9 would fit, but they are 9.25" and the radius I have is 4.75", so I only have an 1/8 inch of space. Is that too small, or does the whole setup move in unison preserving the space?


----------



## toddshotrods (Feb 10, 2009)

octagondd said:


> Quick question, How much space should I have between the drive shaft and the motor for wiggle room. I thought an Impulse 9 would fit, but they are 9.25" and the radius I have is 4.75", so I only have an 1/8 inch of space. Is that too small, or does the whole setup move in unison preserving the space?


Not sure what you're doing there octagon. You gave measurements for the diameter of the motor and (I assume) the available space on each side to mount it, but referenced clearance between the motor and driveshaft? The driveshaft plugs into the back of either the transmission or the motor (in a direct drive setup). Or do you have a transverse setup where the halfshaft passes to the other wheel parallel to the motor?

What is the vehicle? What components/setup do you have? How is your motor located near the driveshaft? Need more information...


----------



## JRP3 (Mar 7, 2008)

His avatar suggest a CRX conversion, I assume transverse mounting. I would not think there should be any flex where the motor moves nearer the axle shaft, but I could be wrong.


----------



## toddshotrods (Feb 10, 2009)

JRP3 said:


> His avatar suggest a CRX conversion, I assume transverse mounting...


Okay, I missed that.



JRP3 said:


> ...I would not think there should be any flex where the motor moves nearer the axle shaft, but I could be wrong.


Probably not, but it could depend on what part of the axle is an 1/8th inch from the motor. The only way I could see it touching is if there is no intermediate shaft, and the axle moves a bit when the wheels are turned. If it's the inner CV assembly, it shouldn't move at all as long as the bearing is good.


----------



## Woodsmith (Jun 5, 2008)

Here's a random question.

The brush boxes on my 12" motor pivot on the mounting post. It means that the brushes can be set either square onto the comm or rotated round at an angle to the comm.









Should they be set square on to the comm and what are the implications if they are not square on or not all exactly the same?


----------



## JRP3 (Mar 7, 2008)

My guess is if the motor won't be reversed then angling the brushes would give a bit more contact area. Pure speculation on my part.


----------



## major (Apr 4, 2008)

Woodsmith said:


> Here's a random question.
> 
> The brush boxes on my 12" motor pivot on the mounting post. It means that the brushes can be set either square onto the comm or rotated round at an angle to the comm........
> Should they be set square on to the comm and what are the implications if they are not square on or not all exactly the same?


Hi Wood,

Just the old fashion way of doing things.  Sometimes you do see brushes angled to the radius of the comm. This will give an increased contact patch area relative to the cross sectional area of the brush. Although the performance advantage of doing such is questionable.

Undoubtedly, the 4 brushes need to be exactly 90° from each other. Otherwise circulating currents will develop running thru the brushes and cross connectors which will not serve a useful purpose, such as producing torque. 

Once the brushes are set at 90° from each other, then as a set, they must be located at the desired location. For reversible or interpole machines, this is on magnetic neutral.

If at all possible, I'd leave the brush position and angle to where it was when you got the motor. 

Cheers,

major


----------



## octagondd (Jan 27, 2010)

toddshotrods said:


> Not sure what you're doing there octagon. You gave measurements for the diameter of the motor and (I assume) the available space on each side to mount it, but referenced clearance between the motor and driveshaft? The driveshaft plugs into the back of either the transmission or the motor (in a direct drive setup). Or do you have a transverse setup where the halfshaft passes to the other wheel parallel to the motor?
> 
> What is the vehicle? What components/setup do you have? How is your motor located near the driveshaft? Need more information...


Ahh yes, you see I know next to nothing about cars, so I called it what I thought it was.(The name of my favorite fictional band from LOST) I am talking about the shaft?/axle? that goes from the transmission to the wheels. One is short and goes to the F.R. wheel and the other is longer and goes to the F.L. wheel. The one going to the F.L. wheel may only have an 1/8th inch clearance between the motor and itself and I'm curious if hitting bumps and the car moving around, etc will caouse it to hit the motor while it is spinning at a high rate of speed.

Dave


----------



## Woodsmith (Jun 5, 2008)

major said:


> Hi Wood,
> 
> Just the old fashion way of doing things.  Sometimes you do see brushes angled to the radius of the comm. This will give an increased contact patch area relative to the cross sectional area of the brush. Although the performance advantage of doing such is questionable.
> 
> ...


Cheers major, originally three where sort of square to the comm and one was angled.
I will set them square on as that will be easier then trying to set an angle and match up on all four.
Thank you.


----------



## toddshotrods (Feb 10, 2009)

octagondd said:


> Ahh yes, you see I know next to nothing about cars, so I called it what I thought it was.(The name of my favorite fictional band from LOST) I am talking about the shaft?/axle? that goes from the transmission to the wheels. One is short and goes to the F.R. wheel and the other is longer and goes to the F.L. wheel. The one going to the F.L. wheel may only have an 1/8th inch clearance between the motor and itself and I'm curious if hitting bumps and the car moving around, etc will caouse it to hit the motor while it is spinning at a high rate of speed.
> 
> Dave


Your description of the part wasn't technically wrong. It is actually a driveshaft, but front-drive and independent rear shafts are commonly referred to as half-shafts or axles (in the U.S.). The only difference is in being able to quickly reference what the part is and where it's being used.

Since you say you're not car savvy, is it the fat or skinny part of the long axle that's close to the motor? Is the axle still in the vehicle? If so, you can check to see if the clearance changes when the front wheels are turned from lock-to-lock (full right/full left).

I agree with JRP3 that the 1/8th inch shouldn't be a big deal, as long as that clearance doesn't change. Turning the wheels, or maybe suspension movement, are the only things I can think of that would move the axle. The motor would be bolted solid to the transaxle (transmission), so they would move together.

It's hard to say really without pictures that let us see where the two parts come close to each other.


----------



## octagondd (Jan 27, 2010)

toddshotrods said:


> Your description of the part wasn't technically wrong. It is actually a driveshaft, but front-drive and independent rear shafts are commonly referred to as half-shafts or axles (in the U.S.). The only difference is in being able to quickly reference what the part is and where it's being used.
> 
> Since you say you're not car savvy, is it the fat or skinny part of the long axle that's close to the motor? Is the axle still in the vehicle? If so, you can check to see if the clearance changes when the front wheels are turned from lock-to-lock (full right/full left).
> 
> ...


The tranny is out of the vehicle and I don't have the motor yet, but right where the axle leaves the transaxle the fat part with the rubber boot on it may come within an 1/8th inch. I put the axle in and it doesn't move around much and as you said the motor, transaxle and axle should all move together

In this picture, the axle on the right is what I am talking about. This is not my setup, just a picture I found in a google search.


----------



## toddshotrods (Feb 10, 2009)

octagondd said:


> ...but right where the axle leaves the transaxle the fat part with the rubber boot on it may come within an 1/8th inch
> 
> ...In this picture, the axle on the right is what I am talking about...


You should be fine. Even if the axle moves the CV joint (fat part with boot) is going to be stationary (moving only with the motor/transaxle assembly). If that clearance changes, you have some other issues that shouldn't be happening. Post more pics when you get the motor, and have it bolted up, if you want to triple check.


----------



## octagondd (Jan 27, 2010)

toddshotrods said:


> You should be fine. Even if the axle moves the CV joint (fat part with boot) is going to be stationary (moving only with the motor/transaxle assembly). If that clearance changes, you have some other issues that shouldn't be happening. Post more pics when you get the motor, and have it bolted up, if you want to triple check.


Thanks so much Todd. I didn't want to have to change my order since I didn't take the CV joint into account when measuring how much space there was.


----------



## few2many (Jun 23, 2009)

What is a good amount to advance brushes? Dependant on speed, voltage and ???
Also, would there be any benefit to have the brushes neutral at the start and advance with throttle, similar to Ignition timing?


----------



## JRP3 (Mar 7, 2008)

I think 10-12 degrees is normal. I know Jim experimented with adjustable brushes rings, don't know the results.


----------



## few2many (Jun 23, 2009)

JRP3 said:


> I think 10-12 degrees is normal. I know Jim experimented with adjustable brushes rings, don't know the results.


Is there as much benefit to neutral timing on start as there is advanced timing at higher rpms and voltages? Or rather, What are the advantages/disadvantages of either?
Also, what are anyones thoughts on using lovejoy couplings? is direct better?


----------



## JRP3 (Mar 7, 2008)

Lovejoy couplings don't seem to be up to the torque, I've seen a number of reported failures with them. Not sure about the neutral timing at start, but I'm not aware of anyone who uses it.


----------

