The statement about the winding fault being relative to armature
position is incorrect. There can be inter-winding faults, as well as a
winding-rotor fault. Only way to isolate it is pull the armature and
test on a growler. The brushes excite windings that are common from
brush-brush and short windings that were once excited to remove stray
currents, so they serve a dual-purpose. Due to that nature, it is also
possible the commutator just needs undercut. That, too, can cause wierd
issues.
Chad
On May 21, 2019 6:22 PM, Chris Zach <cz alembic crystel com> wrote:
Continuing the troubleshooting I took a look at the deck wiring by
removing the wire cover plates. All looked good so I started taking off
the motor wires to isolate the problem.
Sure enough with the center motor disconnected (the oldest one) the
ground fault disappeared. So it's in the motor. I took this one
apart to
check and lubricate the bearings and clean out all the accumulated dust
and junk, so it's not that.
Either it's a short in the armature or in the brush housing. I don't
think it is the armature, as a winding short would only ground fault in
certain rotation points and this is faulting everywhere. So I'll pull
off the cap tomorrow and have a look at the two posts. One of them
might
have a damaged insulator sleeve....
That and fixing the wire on the main motor with a new lug should fix
all
the problems until I can get around to dropping and pulling the drive
motor. Maybe in the fall because I need it now for mowing.
C
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