Message: 2
Date: Sun, 15 Oct 2006 20:58:17 -0400
From: David C Robie <mycroftxx1 juno com>
Subject: Re: (ET) Arcing motor
To: futurev radix net,elec-trak cosmos phy tufts edu
Message-ID: <20061015 213521 -291531 1 mycroftxx1 juno com>
Content-Type: text/plain
Hi Chip
Charger; if it's still there and works, you can take out the GE
countdown timer, and put in an air conditioner type timer (the
plastic
24 hour type you get cheap in hardware stores. The only problem
is that
it repeats the time set in every 24 hrs. To stop this and make it
a 'one
shot' timer, get inside of it and break off the plastic 'pin ' that
turns it on - that way you turn it on then it turns itself off
according
to the time you set and don't repeat. I did this yrs ago to one
tractor
and it's still in there working when I need it (which isn't often
as most
Etractor charging here is solar photovoltaic)
As to motor: Take her apart and see if there is a short caused by
a dig
either between 2 ajacent commutator bars, or at the exposed armature
wires next to the commutator or on the other side of the armature.
This
is often caused by foriegn material (China? Taiwan? or some little USA
thingus that fell into the aircooling vent years ago) - or could be a
little broken off piece of the field magnet scoring the commutator so
deep that it becomes a short, or hittin the armature winding and
shorting
wires together..
Another thing that is known to happen (especially in 12 motors) is
that
the centrifugal 'rpm limit' switch comes apart with pieces making a
short there - or if getting between armature and magnet, locking the
motor up tight. You can do without this rpm limiter (if you have one)
as it's limited by the mechanical resistance of the belt and tranny
gears
even in neutral. I took all gov parts out of my 12 clone (WH 145)
rather
than put it all together and have to pull it apart sometime in the
future
for the same thing, or hunt for a new assy. Motor, because of this
mechanical resistance, does not overspeed.
If you find a short and fix it, clean up the commutator and
brushes,
make sure brushes are not sticky in their holders. I usually stone the
brushholder insides if there is any hint of brush binding. This
binding
could be your 'motor stop' or it could be the circuit breaker
feeling a
partial short and heavy draw in the motor.
Don't worry about a dig in a commutator bar. Fine file the
copper so
it's slick where the brush runs across it nothing protruding no sharp
edges. Make sure the whole bar hasn't lifted up high, if it has,
with a
hammer and block of wood tap it back even with the others.
Done a couple of these (but in an 8 and 12) they are not a big
job
except for getting the motors out to work on. But did a lot of em yrs
ago on prewar vehicle generators, bout the same breed of cat but
have a
wound field.
RSVP to this after you get her apart, let us know what happened in
there.
Armature shorts, unless externally caused and plainly visible as
above,
are very rare.
Dave
Weymouth MA
(NE Chap EAA Sec)