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Old 10-11-2006, 09:55 AM
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pilotpete2
 
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Default RE: Brushed/ Brushless ESC

Actually they are classed as BLDC (brushless dc) as they run in a commutated mode, using dc switched electronically rather than mechanically. The motors themselves are not capable of functioning without either a BLDC or a variable frequency drive that is designed for starting a motor with a permanent magnet rotor. If you were to connect one of these motors to a source of the proper voltage 3 phase ac the motor would not start, it would have to be spun up to synchronous speed by an external power source as the PM rotor cannot accelerate fast enough so it will sit in a stalled condition with no torque produced. The fact that the current flow between the ESC and the motor can be considered "ac" is somewhat confusing since the "commutator" is located external to the motor rather than internal as in a brushed motor, one could easily argue that a brushed motor runs on ac, and they would be "technically" correct, but wrong since the power source is dc, just as the power source is dc for brushless motors. Class dismissed!
Pete