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Electric Motors for Electric Cars

3263 Views 10 Replies 4 Participants Last post by  electronjen
Hi all,

I was wondering if anyone knows of a good place to find NEW electric motors at low cost. I have been looking around, and have found a few good high power (200hp) motors, however they are prohibitively expensive! (>10k)

My company is designing a 150hp motor/controller all-in-one unit that we hope to sell for under $3000. I am trying to get an idea of if something like that is useful for the DIYers out there or not.

What do you guys think?
Thanks :)
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Thanks for all the examples, that is exactly what I was trying to find!

As for the motor design questions, I will try and give a bit more info for you.

We started out designing a motor that would be useful for a different application, namely hybrid aircraft. However I have wanted to convert my old MINI Cooper S to electric for some time now and got to looking at some of the motor prices and specs. Long story short I was not very happy with what I found (some >20k per motor!) and I think that things can be made a bit cheaper without sacrificing too much power.

Our motor would include the controller as it is integral to the design. It is a permanent magnet brushless 2 phase motor with smart Regen control built into the controller circuitry. The torque curve of our system is flat to 20krpm. This coupled with a final drive gearbox would enable a lightweight (prototype is 3 HP per lb ) drivetrain. The design is easily liquid cooled and capable of sustaining 75% rated power. (good point brian_ !)

The voltage is selectable, so it can run on either 50 or 100V (48V or 96V systems are fine) The best is a 48V system for regenerative braking since the motor computer has a special algorithm in it for that. (it maintains a voltage higher than the battery so that regen has steady power throughout the rpm range)

The motor has a unique design which allows it to be made fairly cheaply, so the electronics are our main cost (around $1000 for the controller)

My assumption for mounting hardware is a kit that allows adapter plates for different transmissions/transaxles. Or maybe even a service for that. (give us a dxf, and we cut the plate)

As I stated before we are just in the stage of trying to figure out what people really need/want so that we can build a really good system to fit. We have the motor technology, and engineering experience but the input of the people doing these conversions and work like this is invaluable!
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I just realized that the previous reply I posted, did not post for some reason.

Thanks for all the information, that was exactly what I was looking for. I had a feeling that most people were using used motors from production EVs for conversions. The issue I have with that is that you have to reverse engineer everything and make it fit with your car with very little in the way of engineering data (drawings, CAD files etc..) The companies that do provide motors of this sort are quite small and very expensive for larger HP models.

To answer a few of the questions:

1) Yes the motor would come with a controller with regen, reverse and an interface to customize the power and various parameters. The controller contains proprietary (yet addressable by computer) software that increases the regen efficiency for those with good enough batteries to handle the current. (you can set the max regen current as well)

2) Our idea was to have drawings and a simple bolt pattern so that interfacing to existing transmissions/drivelines would be simple (well as simple as possible!)

3) The motor design is PM and can be manufactured in several voltage ranges. That is another question for all of you. What is the most used voltage range for your conversions?

4) Cost of production for our design is lower because we designed the motor with manufacturing in mind. Once the Jigs are built, it will be simple for an automated process to quickly assemble each motor, cutting cost and increasing efficiency. IN fact the controller is the most expensive part of the system.

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That's the most popular approach for discussion, but I don't know how one would determine the actual number of conversions done with each source of motor.
It would be interesting to know.
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