RE: GROUND FAULT IN MOTOR?

[eric.chang@chrysalis.org]

Hi jrab.  You are correct; it is not a good idea to drive around
with a ground fault in your motor.  Didn't I already post 
something to this effect?  As I mentioned, the ground faults
often occur from to the armature to the shaft.  Are you trying
to locate it?  If so, it is helpful to remove the motor.  
Obviously, that is kind of hard.  Alternatively, you can remove
the brushes and clean the commutator by wiping it with a rag.
Then, test for commutator to shaft/ground shorts.  If you have
one of those, then you probably have an armature wire shorted
to the rotor.  Note that you can also have interwinding shorts
between the two winding layers.  I don't know how to find these
without removing the motor.  You can also check for a stator
to ground short in a similar way (by selectively disconnecting
leads).  Good luck.
 
Eric