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Old 05-09-2010, 01:50 AM   #7 (permalink)
Electric Porsche
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Actually it's the opposite for my motor. Allegedly my Kostov motor is spec'd for 144 Volts, but at 1/3 that (48 V) the fields get pretty hot after 10 or 15 minutes. At 144 Volts I would expect the field to overheat in about 1 minute. One reason to run the field at less voltage is you can ramp it up for regen, down for accelerating, and have some overhead for higher or lower rpm.

I'll parrot what I've heard: There is some difference between shunt and sepex. The field and armature are run in parallel for both. The shunt field is wound with finer wire, and is designed to run at full voltage. This is what you'd do for a constant speed motor, like a conveyor belt or elevator. It would be harder to get regen on a shunt motor, practically speaking you could only do it by physically speeding up the motor as it would be hard to give it higher than pack voltage. A sepex field is wound with somewhat thicker wire, and the field meant to generally run at less than the full armature voltage -- this gives some voltage overhead for regen.
Originally Posted by rmay635703 View Post
Hmm, sounds like you are running a 24v sepex at 72v, most sepex come out of forks and most antique sepex do indeed run straight off the pack voltage, of coarse if you up the ante it will not like more for long.

Of coarse modern sepex use PWM on both field and armature so you can similate different torque and rpm levels.
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