Tony :
A short to ground, which is the most common type, can be detected by
removing the armature from the motor, and using an ohmmeter to check
between the commutator and the shaft. The resistance should be very
high, at least 10 megohms. An inter-winding short (or open) requires a
special machine to detect (commonly called a growler for the noise it
makes) and I've never seen one for a motor this small. In either case,
replacement or rewinding is the only cure. There is no other way, since
the windings all interlock.
However, I completely missed the point about your having the end cap of
the motor off! The symptoms you describe are completely normal when the
shaft is not supported! (My only excuse is that I was up until 6 AM
last night surfin' the 'net)
If I recall your original post correctly, your complaint was that low
speed worked OK, but high speed did not work at all. This almost has to
be an electrical problem, most likely in the wiring external to the
motor. I would find a suitable schematic to verify the correct wiring,
then remove the wires at the motor and make direct connections to the
battery and ground for testing. MAKE SURE THE MOTOR CONNECTIONS ARE
RIGHT or you may burn up the park mechanism, which typically grounds one
of the terminals during part of the cycle.
If you need a schematic, our local club has some nice poster size ones
for sale <g>
Randall
Tony Rhodes wrote:
>
> Message text written by Randall Young
> >You apparently have a short in the armature, most likely from one
> winding to ground, but possibly between two windings.
> Re-winding the armature is another possibility. I've done it
> successfully, but it's a pain.
> <
>
> How would I tell where the short is? Measuring resistance of each contact
> on the
> commutator?
>
> I'd hate to rewind it too!!!!
>
> -Tony
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