Michael A. Terrell Inscribed thus:


Oppie wrote:

"nesesu" wrote in message

...
On Feb 9, 7:57 pm, DaveC wrote:

After you turned the commutator, did you undercut the mica between
the commutator segments? It is critical that the insulation be
below the surface of the copper to ensure good contact between the
brushes and the copper. If there is still sufficient undercutting
[you only skimmed the surface of the comm] then be sure that there
is no copper shorting between commutator bars. The copper often
'smears' a bit when being turned and will bridge the gaps here and
there. A "pole growler" will show up any such shorts.

Neil S.


Been there, did that...
My wife's grandmother was the only person I've ever known that wore
out an old Electrolux vacuum cleaner. When the motor was
disassembled, there was a noticeable groove in the commutator. Put it
on a lathe and turned it down in very small steps, finishing off with
very fine grit on a wet cloth to smooth to a near mirror finish.
Complete by removing any copper flash that wound up in the gaps
between commutators.


I used to turn down commutators on lots of vacuum cleaner motors
without taking them apart. I would run them on a variable DC supply
and
use a hard ink eraser, with it running. Some were so bad that I had
to hit the worst spots with emery paper, but I didn't have a lathe and
it worked.


I've done that with a lolly stick and fine glass paper, then I
discovered the abrasive sticks made just for this purpose.

--
Best Regards:
Baron.