[ausev] A little confused about motors....

[Gil Dawson]

At 6:41 P -0600 5/28/08, evehicle4me at hischopsticks.org wrote:
>  Doesn't DC (from a battery) need to be converted to AC to be able 
>to power an AC motor?

Yes.  That's one of the functions of the controller.  Think 
oscillator and power amplifier.  Then make the power amplifier REALLY 
BIG and connect it to the motor instead of speakers.  When you 
control the oscillator, the wheels follow.

>Is there a significant loss in the process?

Yes, and there's significant compensation.  AC motors are simpler (no 
brushes.)  A sophisiticated controller can control them more 
precisely.  I wonder whether a DC motor can even do regen?  I guess 
it could.  I'd be interested to know whether regen is a typical 
feature of commercially-made DC motor controllers.

GM and Toyota both chose AC in their commercial products, the RAV4EV, 
the Chevy S-10E and the EV1.  The Prius uses two 
separately-controlled AC motors.  The big guys must like 
sophisticated controllers.

--Gil