Ray L. Volts wrote:

Got a GE 4.8A clothes dryer motor here which emitted some smoke one day
shortly after powering it up. I've been using this blower assembly for
solder fume extraction from my bench, so it had no drum loading the
motor down.
I shut it down before the thermal protection kicked in. I then blew all
the dust out that I could get to with an aerosol duster and hooked it up
to a switched, breaker outlet strip outdoors where there would be no
fire hazard (other than to the motor itself) so I could check it out
further.
Powered it up, it ran about 10 secs then smoked again. There was no
duct attached and the bearings turned freely (both before and after the
first smoking event), so it wasn't binding.
Tried it again, this time allowing it to run until the thermal
protection shut it off. After a couple more times powering it up and
letting the thermal protect do its thing, it worked perfectly from then
on – no smoke, no thermal runaway, no noticeable loss in CFM. It
continues to run flawlessly and does not overheat or smoke, even when I
block the inlet to purposely strain the motor.

Question is, what the heck was smoking? If it were dust burning off,
the motor would have had to have gotten hot enough TO burn it off, yet
the first time it only smoked a lot and didn't shut itself down. On the
other hand, if winding varnish were melting off, damaging the motor, why
is there no loss in performance, no more overheating and no signs there
was ever a problem??

I obviously can't trust this motor as I had, even though the thermal
protection does appear to be working properly. This thing would be a
real bitch to disassemble and rewind, though – assuming I can even get
my hands on the right gauges of magnet wire.

So, whaddya think? Should I continue to use this motor and just monitor
it carefully, or should I attempt a rewind just to be on the safe side?
Sure, I could buy another motor ($$$), but as I said, this one IS
working, so I'm not sure replacement is necessary at this point.

Anybody care to share their experience with these motors in terms of
expected lifespan after an overheating incident (or three)?
You're to late, you let the smoke out!... there is no hope now!


--
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:

SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"