# AC 3 Phase Motor- I got it free!!



## JRoque (Mar 9, 2010)

Hi. What's the rated speed, voltage, insulation class, poles? Industrial motors like yours are very heavy mainly because they're cast material. I have an industrial 25 HP that's <150 lbs as it uses sheet of metal of a housing, saving weight. EV motors are even lighter than that.

Assuming the ratings are acceptable for EV use, and most ACIM are not, you can drive it with a VFD and external IGBT switches or module. See Eric's project for reference. I was going down that path for my project until I hit a snag with the motor being too long for my donor car. Bummer. I'm now looking at the AC50 motor with it's Curtis controller.

JR


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## umurali2000 (May 3, 2010)

Have you decided what to do with this motor? I think you can go for making electric vehicle


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## JRP3 (Mar 7, 2008)

Doesn't look as if it can handle higher amps, 62 amp continuous rating and class F insulation. Since I doubt you'll be running 445 volts you'll need much higher amps to get power out of it.


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## JimDanielson (Oct 19, 2008)

> What's the rated speed, voltage, insulation class, poles?


The requirements by the locomotive manufacturer are: 4 poles, class F, 22hp at 133.3 hz, 445 volts

I cannot post the whole spec here but one point is:
-The motor will be subject to diagnostic testing utilizing a 2500VDC insulation tester.

These requirements are defined by the locomotive manufacturer. The motor manufacturer must put these specs on the motor. So in theory, the motor manufacturer may have rated it higher. This motor is designed for a traction motor blower. The traction motors on a locomotive can handle 2000hp



> Since I doubt you'll be running 445 volts you'll need much higher amps to get power out of it.


I was thinking I could put 140 LiFePo4 cells in series. Probably the 40Ah or 50Ah style. The only pain would be balancing that many cells in series.



> Have you decided what to do with this motor? I think you can go for making electric vehicle


4 thoughts currently:
-make a genset trailer for my electric porsche so I can go further (although the output voltage will be much too high)
-replace the series forklift motor in the porsche
-start a new conversion (I don't particularly want to upgrade the porsche because if I upgrade one thing, everything needs to be upgraded, might as well start a new conversion and get the IL gov to subsidize the cost again)
-use it for purdue's electric indi 500 car we might be starting soon


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## major (Apr 4, 2008)

jimbo12d said:


> The requirements by the locomotive manufacturer are: 4 poles, class F, 22hp at 133.3 hz, 445 volts
> 
> -The motor will be subject to diagnostic testing utilizing a 2500VDC insulation tester.


Hi jimbo,

Comments/issues:

The insulation test you site is just that. Not a running condition.

445 VAC would need on the order of 700 VDC into the inverter.

TEFC, 22 hp rated continuous for a 290 lb motor is poor power density for an EV. In other words, it is too heavy. Reliance makes great motors. I have no doubt this beast does an excellent job providing 22 hp at 4000 RPM in the locomotive for millions of miles. But this type of motor design and construction is not needed in an EV which may run tens of thousands of miles in its life.

Maybe it can be altered to function in an EV by rewinding and rebuilding, but after all that, you likely would fare better starting with a different motor.

The little controller device you site is a speed controller. You need a torque controller. You will have difficulty/expense finding a suitable controller.

Free stuff is great. But can suck your life blood trying to get it to work 

major


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## thingstodo (Jul 16, 2010)

jimbo12d said:


> The requirements by the locomotive manufacturer are: 4 poles, class F, 22hp at 133.3 hz, 445 volts


I get around 4000 rpm from the 133 hz. That'd be fine for a maximum speed.

I have to agree with the posting about the motor being too heavy for the power.

I've run industrial motors at 200% - 300% rated current for minutes at a time. The motor torque is not linear, you get more extra torque from 100 - 200% than you do from 200 - 300%.

I calculate less than 30 foot-lb of rated torque at 4000 rpm, 22 hp. That's may be low for an ev that could accommodate the weight. Even 300% is quite low for acceleration.

With that weight, you might be able to go higher, maybe 500% or 700% current for acceleration. With the 2500V insulation test, you might be able to use a european 690 VAC VFD, at over 1000 VDC on the DC bus. That's a lot of batteries, and a lot of weight.

Depending on the type of motor, you may be able to re-arrange the motor windings for higher torque ... not my area of expertise, just some stuff I've read about.

thingstodo


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## samborambo (Aug 27, 2008)

This is a good score for a free motor! Off the shelf they'd be around US$1500. Something a bit odd with the electrical ratings. I calculated around 37.4kW mechanical (assuming 0.85 power factor). Maybe that's a higher service factor? Who knows. Anyway, as has been said already, you should be able to get at least 3x power/torque out of a typical induction motor.

I have a similar size/weight/power/poles/voltage motor that I'm using for my MR2 conversion. Long battery strings make the current more manageable but the BMS gets rather expensive. Initially I ran through ideas of reconnecting the windings for a lower voltage / higher current (still viable) or just going with an HV string. In the end I've decided to add a 250VDC - 750VDC multiphase (3p) boost DC-DC converter since I have a good supply of cheap 1200V 100A IGBT six packs. 

This gives me two DC buses. First the HV bus (250 - 750VDC) between the DC-DC converter and the 3p HV inverter . Second is the LV bus (250VDC nominal) between the DC-DC and the main battery string. So far I've simulated the whole system and will hopefully be ordering parts soon. 

Having the multiphase boost converter has a few benefits:

Reduces the size/cost of the DC bus capacitors or much less current ripple from the battery.
Reduces RFI caused by di/dt.
Allows connection of a high voltage (3p 415VAC in my country) charging source. Rectify it straight from the source (with some filtering) for fast charging.
Boost converter can act as a fast charger.
If you're not planning on doing anything too serious in electronics design, I suggest you get the motor rewound or reconnected to a more appropriate voltage for the battery pack and motor controller you have in mind (VAC = VDC/1.41). It shouldn't cost anything more than US$500 to have it rewound. 

Sam.


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## JRoque (Mar 9, 2010)

Hi Sam. 



> I've decided to add a 250VDC - 750VDC multiphase (3p) boost DC-DC converter since I have a good supply of cheap 1200V 100A IGBT six packs.


Am I reading this correctly that you plan to run your motor controller off a DC/DC boost?

Got a diagram of that DC/DC boost converter? I'm mostly interested in seeing the transformer specs for such a high power boost circuit. Actually, I'm very interested in the entire circuit  I also have some IGBTs for such application but its the other components that are hard to come by.

JR


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## JimDanielson (Oct 19, 2008)

Very cool idea (samborambo), and thanks everyone for the info. I am a EE undergrad student right now so I would be up for the challenge (besides time being an issue). I made a series wound motor controller and I'm working on a brushless controller. This motor has been set on the backburner because a vehicle and large amount of money have yet to be found.

I am thinking about adding regen ability to my series controller (for perm mag motors only) but I read I need a boost converter to get motor output voltage high enough to charge batteries (maybe there is another way?). 

I am not exactly sure how they work, so I would be glad to see your schematic on your boost converter. I might also look into the cost of rewinding the motor, but boosting the voltage would also be cool. Id rather not run a 450+V battery pack, too much bmsing and very dangerous to work on.


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## samborambo (Aug 27, 2008)

JRoque said:


> Hi Sam.
> 
> 
> 
> ...


I haven't got a diagram with me. Looks the same as a standard synchronous boost (or buck, depending on the current flow) but is operated as a single switch+diode. Three converters and inductors in parallel, running 33% duty cycle 120deg out of phase. No transformers since its not an offline design. From memory each inductor is 500uH @ 100A.

Sam.


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## JRoque (Mar 9, 2010)

> each inductor is 500uH @ 100A.


Hi Sam. Yes the inductor is what's usually a hard find. Not sure if you plan to roll your own or if you have a source that can candle 100A at that inductance. As I've posted elsewhere, magnetics are voodoo craft to me.

Looking forward for when you have the schematic ready and can post it.

JR


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## Pirape (Feb 26, 2009)

If you cant use it. No one is holding you off from selling it for 1k and buying the one you need for your project


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## JimDanielson (Oct 19, 2008)

Ha, thats always an option. But, the company I interned for gave it to me hoping to see me use it. I'd really like to use it, just probably not until next semester, this will be the planning semester

Where do you get 100A inductors?


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## samborambo (Aug 27, 2008)

jimbo12d said:


> Ha, thats always an option. But, the company I interned for gave it to me hoping to see me use it. I'd really like to use it, just probably not until next semester, this will be the planning semester
> 
> Where do you get 100A inductors?


Definitely roll your own at this I & H. poweresim.com has a good magnetics builder. Just click on the blue button on the left side.

Sam.


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## DIYguy (Sep 18, 2008)

major said:


> Hi jimbo,
> 
> Comments/issues:
> 
> ...


Hey Major... just a general question.... Excuse me if this has been covered, but I got a gazillion hits without specifics.... I am no motor expert and often wonder.....
There are a ton of 3 phase industrial motor out there intended to be work horses at set speeds (based on 60hz). Like this motor, they tend not to be well suited to VFD applications as seen in EV's. What specifically should folks look for when trying to distinguish if a 3 phase AC motor is a good pick for VFD application? I'm aware of "Inverter Duty" motors which I think are an obvious good choice as they tend to take higher voltages and can run cooler at lower speeds. What else should we look for? Max higher RPM rating? Different bearings?.... 

Thanks.
Gary


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## major (Apr 4, 2008)

DIYguy said:


> There are a ton of 3 phase industrial motor out there intended to be work horses at set speeds (based on 60hz). Like this motor, they tend not to be well suited to VFD applications as seen in EV's.


Hi Gary,

This particular motor, by the nameplate, is designed for 133 Hz, not 60. And I imagine it is well suited for VFD. Although I don't know how the railway application powered it. And this motor could do perfectly well propelling an EV at high higher speed and power than the nameplate indicates. But  you'd need a couple thousand volt battery and have to contend with someway to cool it.



> What specifically should folks look for when trying to distinguish if a 3 phase AC motor is a good pick for VFD application?


An applications engineer



> I'm aware of "Inverter Duty" motors which I think are an obvious good choice as they tend to take higher voltages and can run cooler at lower speeds. What else should we look for? Max higher RPM rating? Different bearings?....


The "inverter duty" motor is likely just a standard duty NEMA motor which has better insulation on the magnet wire and some will have a separate motor powering the fan to cool the frame at low speeds. But just as folks run forklift DC motors at higher voltage, and therefore higher speed and power, than the nameplate, I suspect you'd want to do a similar thing with the NEMA induction motors. In which case, I would look for ones labeled "premium efficiency" meaning they may use more copper and higher grade laminations, sometimes even larger core. But these haven't been around that long and cost more for the original user, so likely aren't showing up on the surplus market.

I suspect most standard NEMA induction motors are capable (mechanically) of any RPM you would be able to drive them to. Just may not be balanced to do much higher than the nameplate. These types of motors likely have suitable bearings, however will likely have grease fittings for service, unlike most of the DC motors having high temperature seals and permanently lubricated bearings.

edit...Guess I hit the wrong key or button and this got posted before I proof read it or signed off on it. Oh well. Guess I was about done. Just that applying an industrial induction motor to your EV ain't easy. Unless you got an uncle in the VFD business, you'll have a tough time. A few have done it, sure. But not many.

Regards,

major


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## samborambo (Aug 27, 2008)

Another consideration when running an induction motor on a VFD is induced shaft current. The bearings should be insulated to keep the shaft loop open. The shaft coupling or clutch into the gearbox should be insulated also. I've got an HRC flexible spider coupling between the motor and gearbox.

The drivetrain will run OK with normal bearings only they won't last as long. I've still got standard bearings in my motor so I'll just have to see how long the last and whether it's worth replacing them with insulated bearings. The bearings in the motor are cheap and easy to get to but I wouldn't fancy stripping down the gearbox and trying to find spare bearings.

Sam.


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## JRoque (Mar 9, 2010)

Hi. A few weeks ago I came across this paper on inverter induced voltages and the effect on bearings: http://www.ab.com/support/abdrives/documentation/techpapers/ieee/APEC95 bearing.pdf Excellent article indeed.

JR


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## DIYguy (Sep 18, 2008)

What do you think of this little guy?  It's new old stock....never used. Even has an encoder on the back. Have to loose the big brake though.... 
Maybe good for a little car?


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## DIYguy (Sep 18, 2008)

I found this little blurb regarding "Inverter Duty" from a motor website... pretty much what Major said...

*In summary, general purpose motors can be run with drives in many applications; however inverter-duty motors are designed to handle much lower speeds without overheating and they are capable of withstanding higher voltage spikes without their insulation failing. With the increased performance comes an increase in cost. This additional cost can be worth it if you need greater performance.*


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## JRP3 (Mar 7, 2008)

DIYguy said:


> What do you think of this little guy?  It's new old stock....never used. Even has an encoder on the back. Have to loose the big brake though....
> Maybe good for a little car?


Really little, cooling might be an issue.


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## major (Apr 4, 2008)

DIYguy said:


> What do you think of this little guy? Maybe good for a little car?


Hi guy,

That is a nice motor. Likely iron frame, so maybe 170 lbs guessing. It is TENV rated at 7.5 hp continuous. Another guess, at that average power it will take 1 to 2 hours to reach stabilized class H temperature. So you could overload it and get maybe 3 times the power from it for shorter times and/or intermittently. But if your EV has the battery to run for an hour or longer, you'd need to stay around 7.5 hp average or you'll risk motor overheat. Blowing air over the frame will only help a little, mostly on the long runs, not the short overloads.

So is an 8 or 9 hp motor enough for your little car? And with induction motors, you don't get the starting torque like from series DC motors, so keep the tranny.

And then you'd better oversize the VFD and get one with flux vector true torque control. Maybe up in the range of 20 kW. And you'd need a 350V battery. Or better yet, a 700V battery and leave the motor connected in the 230V mode for double the power (at twice RPM). But even that won't change the continuous power capability of the TE motor.

So, can you better cool the motor? Not easily. Unlike DC motors which have space in between the field coils, induction motors have little space through which to blow air inside the frame. Some improvement could be realized blowing in and out of each end. Effective enough? Don't know.

Might work 

major


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## DIYguy (Sep 18, 2008)

yes, it is a nice motor... and it's not that little. It's about the same size as my 9" GE. Maybe a little shorter, but must be 9" across anyways. I know a guy who has one of those little 2 seater Suzuki 4wd cars with a back like a small truck... I dont know what its called ...but it would make an awesome EV. Has a full frame and probably doesn't weigh more than 1600 lbs (guessing). Might be good for that....


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## DIYguy (Sep 18, 2008)

major said:


> So, can you better cool the motor? Not easily. Unlike DC motors which have space in between the field coils, induction motors have little space through which to blow air inside the frame. Some improvement could be realized blowing in and out of each end. Effective enough? Don't know.
> 
> Might work
> 
> major


There are 3 or 4 fairly large-flat areas on the frame...maybe one could mill them flat and bond some nice full length heat sink/fins.... ??



major said:


> And then you'd better oversize the VFD and get one with flux vector true torque control. Maybe up in the range of 20 kW. And you'd need a 350V battery. Or better yet, a 700V battery and leave the motor connected in the 230V mode for double the power (at twice RPM). But even that won't change the continuous power capability of the TE motor.


How about a 25 hp Allen Bradley 1336 Impact VFD?


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## major (Apr 4, 2008)

DIYguy said:


> There are 3 or 4 fairly large-flat areas on the frame...maybe one could mill them flat and bond some nice full length heat sink/fins.... ??


Likely not worth it.



> How about a 25 hp Allen Bradley 1336 Impact VFD?


Does it support closed loop flux vector mode?


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## DIYguy (Sep 18, 2008)

major said:


> Does it support closed loop flux vector mode?


No idea.... The drive can be programmed to operate
as a velocity regulator, a torque regulator, or a combination of the two. The 1336 IMPACT™ drive is a Field Oriented Control using the patented FORCE Technology and as such uses data from the motor to determine the active current and excitation current values

Spec sheet blurb....
[h3]1336 IMPACT AC Drive (1336E)[/h3]
The 1336 IMPACT™ AC drive with Force Technology provides the precise motor speed and torque control necessary to handle some of the most demanding drive applications, including many that are typically reserved for DC drives. Force Technology, an Allen-Bradley patented Field-Oriented Control method, has a proven and unique ability to separate and independently control motor flux and torque allowing the 1336 IMPACT drive to deliver full torque down to zero speed.
[h4]Features[/h4]


Force Technology™ for demanding speed and torque performance with or without an encoder
Patented current regulator for true control of motor torque, delivering full torque at zero speed
Simple start-up for fast commissioning and quick auto-tuning of speed and torque using motor nameplate data
16-step speed profiling feature for changing speed based on time, encoder counts or hardware inputs through the L-option card
Encoderless Switchover allows the drive to continue operation if encoder feedback signal is lost, minimizing downtime
SCANport™ protocol provides common interface for programming devices
Internal Process Trim Controller for integration with tension transducer devices
Common power platform of 1336 PLUS II and 1336 FORCE™ family of drives
Motor Temperature Compensation for matching actual torque output to the desired torque without using costly motor temperature sensors
Basic Function Block Programming for specific applications adding flexibility to the drive
Does that help? (I'm a Welding Engineering guy)


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## JRP3 (Mar 7, 2008)

DIYguy said:


> I know a guy who has one of those little 2 seater Suzuki 4wd cars with a back like a small truck... I dont know what its called ...but it would make an awesome EV. Has a full frame and probably doesn't weigh more than 1600 lbs (guessing). Might be good for that....


Was it an X90?


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## DIYguy (Sep 18, 2008)

Suzuki X-90...! that's it... lol looks like this. Its heavier than I thought. It's like 2500lbs!


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## DIYguy (Sep 18, 2008)

JRP3 said:


> Was it an X90?


YES!  Thank you....


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## JRP3 (Mar 7, 2008)

I always thought they looked neat, don't know if they are any good or not. Apparently not many made it into North America, I think I've only seen one or two in the wild. 2500lbs isn't too bad for a 4wd vehicle, my Fiero is 2500lbs.


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## DIYguy (Sep 18, 2008)

JRP3 said:


> I always thought they looked neat, don't know if they are any good or not. Apparently not many made it into North America, I think I've only seen one or two in the wild. 2500lbs isn't too bad for a 4wd vehicle, my Fiero is 2500lbs.


The guys that have them swear by them. My friend loves his. I always thought it would make a great EV. I keep bugging him to sell it to me... lol


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## DIYguy (Sep 18, 2008)

Sorry for hijacking....


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## major (Apr 4, 2008)

DIYguy said:


> > Force Technology™ for demanding speed and torque performance with or without an encoder
> 
> 
> Does that help? (I'm a Welding Engineering guy)


 
Sounds encouraging. But I have never used one of those drives. So I can't say for sure. And there are a number of other little "things" you need to do to get them to work well on a DC supply and give you good control. 

I'll bet nobody has ever taken this advice although I give it often. They likely make a product line all using the same control card. Get the 1/2 kW model and a 56 frame motor, encoder, battery and see if you can get the thing to work powering a flywheel. If you can't do that, you'll have wasted $100s instead of $1000s.

I can't walk it thru for you from here. You got to figure it out for yourself. And better to do it on the bench than in the vehicle.

Regards,

major


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## DIYguy (Sep 18, 2008)

major said:


> I'll bet nobody has ever taken this advice although I give it often. They likely make a product line all using the same control card. Get the 1/2 kW model and a 56 frame motor, encoder, battery and see if you can get the thing to work powering a flywheel. If you can't do that, you'll have wasted $100s instead of $1000s.
> Regards,
> major


Yup, good advise. I doubt I will proceed with another build any time soon though. I do have access to a number of drives/motors for dirt cheap though...if I decided to pursue it. I think the "Impact Drive" starts at about 7.5 hp and goes up to several hundred. They do make a number of different models though.


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## samborambo (Aug 27, 2008)

I think you're better off just studying the VSD's manual to determine whether your control scheme is going to work. From there you'll be able to work out how to interface to it and set up the operating parameters, etc.

Sam.


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## major (Apr 4, 2008)

samborambo said:


> I think you're better off just studying the VSD's manual to determine whether your control scheme is going to work. From there you'll be able to work out how to interface to it and set up the operating parameters, etc.


Yeah, that always is better than hands on experience


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## samborambo (Aug 27, 2008)

major said:


> Yeah, that always is better than hands on experience


Yeah, like trying to assemble flat pack furniture without reading the instructions....


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## DIYguy (Sep 18, 2008)

both practical experience and documentation are of tremendous value...this is for sure. Thank you both. We all have different experiences and mine are not in this area so much (although getting more ) I also found that the electricians and technologists, in our hi-tech manufacturing plant, who read the manuals were usually able to solve the problems. Imagine that. I know I have dug the instructions out of the garbage more than once to complete that seemingly simple assembly of Chinese bits and pieces.... lmao....


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## DIYguy (Sep 18, 2008)

major said:


> Hi guy,
> 
> That is a nice motor. Likely iron frame, so maybe 170 lbs guessing.
> 
> major


I had another look. It's actually an Aluminum frame... so, maybe a bit lighter?


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## thingstodo (Jul 16, 2010)

DIYguy said:


> There are 3 or 4 fairly large-flat areas on the frame...maybe one could mill them flat and bond some nice full length heat sink/fins.... ??
> 
> 
> How about a 25 hp Allen Bradley 1336 Impact VFD?


www.ab.com, on your left select product library, literature library, put 1336 Impact into the search window. You'll get a dozen or so manuals.

The impact is second generation sensorless vector. I have only one at work since the mill was 'testing the waters' and only put in one or two of each type when they were deciding if these VFDs were a good replacement for the fluid couplers (and they were). I also have a couple of older 1336 Plus and 1336 Plus II at the mill and they are still running 15 years later.

Torque control is a good feature - more like an ICE accelerator than speed control is.

A 25 HP VFD driving a 7.5/10 HP motor is a pretty good match. I didn't catch the voltage on the VFD. 

For short periods (like acceleration) you can go 2 - 3 times current to the motor without damage to the motor. VFDs in that family state somewhere in the manuals that they will do 150% rated current for about 30 seconds. 30 seconds is pretty convenient for accelerating a vehicle.

I think that if you check out this EV calculator some of the smaller cars can cruise at 40 mph with 7.5 hp (around 22 ft-lb of torque at 1800 rpm).

http://www.evconvert.com/tools/evcalc/

I think you might be able to get a bit more power out of the motor since there is a 40 mph wind going by the motor ... but that's just my opinion. 

thingstodo


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## DIYguy (Sep 18, 2008)

Thank you "thingstodo"... (nice name) lol. I did look on the website last week. Unfortunately, out of all the AC drives we had in the plant I worked... probably 40 or 50 of them...they are all 380 to 480 volt ..B series. I was hoping to find an A series 200 to 300 volt input....


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## JimDanielson (Oct 19, 2008)

If a boost converter was done from ~100v to 450v, would regen still be possible? A standard boost converter only works in one direction, correct?


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## samborambo (Aug 27, 2008)

jimbo12d said:


> If a boost converter was done from ~100v to 450v, would regen still be possible? A standard boost converter only works in one direction, correct?


Single switch boost converter, yes, one way. A synchronous boost converter can operate in both directions. MOSFETs are considered more appropriate since they're bidirectional. IGBT synchronous converters also work but only one switch at a time for each direction as the inductor free wheeling current just goes through the parallel RB diodes.

If you're thinking of designing a boost converter, it makes sense to work in multiples of the battery voltage eg: 150VDC to 450VDC is a multiple of 3. Design a boost converter with 3 parallel synchronous converters each running a duty cycle of 33% and interleaving phases. Interleaving parallel phases have a lot of advantages such as reducing the ripple current immensly and reducing the bulk storage capacitor required. The downside is more silicon and expensive inductors for each phase leg.

Sam.


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## Alexander_B (Oct 19, 2010)

heh, thats just what I've been looking at, I *might* have found a nice inductor too (100A capable, I'll have to look into that some more) but finding a proper 3phase motor isn't too easy, but with some luck, its cheaper than a (new) dc motor even, just 5000% more hassle to get working.


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