# Would a 3 Phase 10 HP 1750 rpm Motor Work For An EV Car?



## subcooledheatpump (Mar 5, 2012)

You'll need an AC controller, and you'll need a high voltage battery pack. 

340 Volts DC for 240 3 phase AC. 
680 Volts DC for 480 3 phase AC.

Or you could get the motor rewound and use a lower voltage.

You could use an industrial AC controller, but you'd probably want one with true sensored vector mode. 

You might be able to get 40 HP out of that motor if you do it right


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## EV2323 (Jun 7, 2012)

subcooledheatpump said:


> You might be able to get 40 HP out of that motor if you do it right


So it could work for maybe a 2000 lb car? Or what would the weight limit be?
What transmission would be best with such a motor?
Thanks


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## subcooledheatpump (Mar 5, 2012)

The motor could work in any size car. 

What are the specifications of the original engine? 

I estimate that the motor can output 120 FTLBS torque peak with the right controller, if that is close to what the original engine produced, then you should be able to keep the existing transmission.


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## EV2323 (Jun 7, 2012)

Thanks again subcooledheatpump,

A compact pickup truck is popular for EV conversion and that would be OK; but what I would really love to do is a small minivan (like a Mazda MPV).

I realize that most EV conversion vehicles are under 3500 lbs curb weight, but there are a few minivan models close to this. And also that automatic transmissions are not popular because the motor needs to be “running all the time” – don’t understand why though – and all minivans I've seen are automatics.

Thanks

Specs for the Mazda MPV
Curb weight: 3794 lbs.
Base engine size: 3.0 L
Torque: 200 ft-lbs. @ 3000 rpm
Horsepower: 200 hp @ 6200 rpm
Drive type: front wheel drive
Transmission: 5-speed automatic


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## subcooledheatpump (Mar 5, 2012)

You won't be going very fast, but your 10 HP could work. 

You may need to do some electronics work to keep the transmission in first gear.


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## EV2323 (Jun 7, 2012)

subcooledheatpump said:


> You won't be going very fast, but your 10 HP could work.


Acceleration or top speed?


subcooledheatpump said:


> You may need to do some electronics work to keep the transmission in first gear.


First gear at all speeds?
Thanks

Also, I've read that you can use 3 phase motors for regenerative braking. Would regenerative braking require a special transmission?
Thanks


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## subcooledheatpump (Mar 5, 2012)

Yes you can use the motor for regenerative braking, and your top speed and acceleration would both go down compared to the original engine. An automatic transmission should be able to feed back into the motor, as long as it stays in low gear and not overdrive. 

You could use an industrial controller for the idle though, since they have a minimum frequency setting (that keeps up the hydraulic pressure in the transmission) Or you could use a seperate hydraulic pump.


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## EV2323 (Jun 7, 2012)

Thanks for your patience and great info.
Reading on another page convinced me to go the 3 Phase / AC route for real world performance. Don't know if that is still accurate. Is there a good thread on this argument?

There is a forklift place about 40 minutes from me and a 3 Phase motor surplus place closer than that.

If you were trying to do a minivan conversion, what route would you go? Roads can be a bit hilly around here -- not huge hills, but not flat either.

Thanks


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## subcooledheatpump (Mar 5, 2012)

Personally, I would go with a 3 phase motor, but thats just me. 

I have an extended van (8000 LBS) with a 30 HP 3 phase motor in it, works great (apart from it needs a replacement controller) 

But it really depends on what you want to do. AC is complicated because of the lack of cheap controllers. You can of course use an industrial controller but they can be a bit of a pain to configure. Plus industrial controller of that size are rather big and expensive. You can always modify one, that takes electronics expertise. You can also buy an AC controller, but they are very expensive and ver hard to get even if you do have the money

Going DC is the cheaper and eaiser way, though the motors aren't the same. You won't be able to stall a DC motor, and you won't be able to spin one as fast. No regenerative braking either. 

So it's up to you, either one would work, but they each have their own advantages and disadvantages


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## EV2323 (Jun 7, 2012)

subcooledheatpump said:


> I have an extended van (8000 LBS) with a 30 HP 3 phase motor in it, works great (apart from it needs a replacement controller)


Wow, awesome. So it really is possible. Since doing it AC depends on getting a controller, this makes me ask: How are those expensive EV AC motors, that are paired with expensive EV AC controllers, different from the standard industrial 3 phase motor (besides a $300 vs $7000 price tag)?



subcooledheatpump said:


> You won't be able to stall a DC motor, and you won't be able to spin one as fast.


What do you mean by stall (not a bad thing)? And what is limiting the rpm in a DC?

Thanks


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## subcooledheatpump (Mar 5, 2012)

You cannot stall a DC motor ( 0 RPM) with full current applied) the brushes will burn/melt.

The brushes also limit the maximum speed 

"Made for EV" AC motors are wound or rewound for a lower voltage, something like 200 volts whereas an industrial AC motor would need a battery voltage of atleast 340 volts DC. The controllers are often waterproof and liquid cooled units whereas industrial ones are air cooled with big heavy heatsinks, and EV controllers are setup for use in a car rather than a constant load. 

Whats more the motors may be made with low loss laminations so they can work at higher speeds without wasting energy due to things like eddy current losses (think induction heater) The motors may also be liquid cooled, therefore making them smaller and lighther. 

My van did work very well for about 1 year with my modified industrial controller, but I'm in the process of making a new controller for it. It also of course had the industrial motor, but it's 400 lbs. It is possible but not easy


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