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08.22.2008, 08:18 PM
Well, my $.02:
There are electromagnet-electromagnet motors today -- just open up a plug-in hand drill and you'll see one. They need a lot of cooling because they just aren't all that efficient (double the I^2R losses.)
Induction motors are great, and can be very efficient, but they are expensive to control, and don't scale DOWN very well -- and they are VERY heavy compared to DC brushless (which is really a three phase AC permanent magnet motor) for the same power output. And they don't scale well for high RPM applications -- the rotor losses get really high at high RPMs.
So for the hobby, and for any application where highest power to weight ratio is required, you just can't beat a DC brushless motor.
Patrick
Patrick del Castillo
President, Principle Engineer
Castle Creations
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