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

[tomsmail at wtez.net]

The bigs have to like AC induction motors because they're cheap, reliable,
and safe.
-No sparks to kill anyone (whose survivors might sue)
-compleatly sealable, no dust dirt or grime to get inside the case, no
worries about brushes , and no worrying about water getting in).
-practically speaking, very little mechanically can go wrong.
-copper is cheap compared to permanent magnetic material (so i've read).

The controller is more expensive, but electroncs have a lower mortality
rate then mechanically complex devices, generally, so its a necessary
evil, so to speak.

Tom




> 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
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