[GTALUG] mysterious restarts

[phiscock at ee.ryerson.ca]

> Most people think 60Hz when they think AC.  But I would guess that in
> a motor AC is timed to the rotation so that commutators (I think
> that's what they are called) can be eliminated.
>
> Would that AC be 60Hz or would it be variable, matching some function
> of the motor's current speed?

Variable speed AC motors use a variable frequency alternating current.
Sometimes you can hear the frequency as it increases when the vehicle is
starting. The alternating current creates a rotating magnetic field which
'carries along' the rotor.

P.

-- 
Peter Hiscocks
Syscomp Electronic Design Limited, Toronto
http://www.syscompdesign.com
USB Oscilloscope and Waveform Generator
647-839-0325