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build a motor-generator based on a automotive alternator stator

Posted: Jan 17 2020 5:11pm
by jlcortex
hello all,
I want to make a motor-generator of about 22kw based on this existing stator:
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It is 48 slot 126mm internal diameter, it is for a 16 magnet rotor

I would like some advice. I am drawing a IPM rotor because it seems easier than external magnets and more robust.
I thought about a V design because i see all EV motors are using this rotors, but It seems it is difficult to get the exact magnet i need and, I have found a magnet (25x6x2 45SH) and it seems perfect for this rotor design:
rotor1.JPG
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motor1.JPG
motor1.JPG (33.15 KiB) Viewed 851 times
it have 192 magnets!

but the main problem seems the lamination, I have been researching about lamination prototypes, I have to ask some companies but it seem not cheap.

What do you think about use 0.5mm mild steel? for a stator is very bad, but it is a rotor.
And it is a prototype, using a common steel would make things a lot easier because I can do it here with a local laser cutting supplier.

Re: build a motor-generator based on a automotive alternator stator

Posted: Mar 04 2020 11:16am
by jlcortex
I have built the motor and tested it in short-circuited stator
I am using a motorcycle chasis dyno to measure torque. I accelerate the roller (flywheel) and measure negative torque until roller stops.

It gives me about 19Nm when it should be something about 90Nm

I think I made a mistake, I have ordered the lamination in carbon steel (laser cut), it is not a magnetic steel, I thought it would not be a problem because it is the rotor and the magnetic field does not change as much as in the stator.

maybe there is my mistake?

Re: build a motor-generator based on a automotive alternator stator

Posted: Mar 04 2020 11:23am
by jlcortex
some pictures of the process

Re: build a motor-generator based on a automotive alternator stator

Posted: Mar 04 2020 5:59pm
by spinningmagnets
Thanks for posting, this looks like an interesting project. Of course, a motor that is designed from the beginning to be a motor will always be the most powerful per volume, and the most efficient, but...alternators are just about the right size, and I don't believe that anyone has designed the definitive alternator conversion. If an alternator is converted to a motor using the best possible design, it might actually be pretty good.