On 4/26/2012 8:04 AM, Michael A. Terrell wrote:
klem kedidelhopper wrote:
On Apr 24, 7:52 pm, "Michael A.
wrote:
klem kedidelhopper wrote:
Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny
Try running the motor on 12 to 24 VDC to seat the new brushes. I
used to polish the armature with a gray ink eraser while running the
motor this way, when I repaired vacuum cleaner motors.
The new brushes are pretty well shaped to the arc of the commutator
but I guess it doesn't hurt to try. You can do this to a 120VAC motor
without hurting it though? Lenny
I rebuilt hundreds of motors with no problems. A variable power
supply is great. Most of the motors ran the right speed between 6& 16
volts. The wide gray eraser is used to polish the surface and reduce
arcing. Polish the armature, and let the motor run at the reduced speed
for a while to seat the brushes. Use just enough pressure to just
slightly slow the motor. This will prevent the eraser from getting hot
& melting or burning. I used to refer to the process as a 'Briarhopper
Armature Lathe'. I refused to show anyone how I took a nasty, worn
armature and made them look brand new, but they kept coming back for
rebuilt motors for their used vacuum cleaner business. The best part
was that they would give me hundreds of motors that 'Aren't worth
fixing', then buy them back. ;-)
Even though the curve is close, they aren't a great match until they
are run for a while.
http://ak.buy.com/PI/0/500/208376870.jpg shows the type I used. I
used to be able to buy solid gray, but this type should work OK and
should be available anywhere that sells a decent selection of office
supplies.
There used to be a specific abrasive 'stone' used for that process and
it was very effective, especially where a high power tool had to be
ready for use immediately (seating the brushes that is).