Re: (ET) Using 4QD controllers

[Bill Alexander <wca1 humboldt edu>]

Without any personal knowledge of wheelchairs, I believe the "brake
circuit" is actually a brake release circuit.  You wouldn't want the
wheelchair to go freewheel in the event of an electrical failure or dead
battery (there is probably a manual release).


>
>I believe the 4QD controllers, which are actually designed for permant
>magnet motors, are based on a wheelchair controller design (someone 
>correct
>me if I'm wrong).  So apparently they have a circuit which can be used to
>apply a brake when the power is off.  It releases the brake right before
>applying power to the armature, and sets it when the motor is fully 
>stopped -
> this is exactly the behavior you want for the motor's field, too.  So you
>can use the brake drive to properly power a separately excited wound field
>for the motor.  (BTW, permanent magnet motors were used in the E8 and E10
>tractors.)
>

Bill Alexander                         Excuse me if I ramble,
Physics Dept.                          but I drive a Nash.
Humboldt State University
Arcata,  CA  95521

phone: (707) 826-3212
e-mail: wca1 humboldt edu
http://sorrel.humboldt.edu/~phyx/faculty/alexander.html