Dryer motor smoker

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)?

Reply to
Ray L. Volts
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Reply to
hrhofmann

Is there a centrifical (sp?) switch that opens a starting winding that maybe wasn't opening due to some dirt???

Reply to
hrhofmann

Maybe some sort of start circuit failed to switch off causing the smoke/problem but it's impossible to be certain without the model # of the motor.

Reply to
Meat Plow

Even if you had the model number for the motor, what good would it do? It was probably made just for that series of dryer so that's probably all it will get you, not technical details of what they consider a non serviceable component.

Reply to
James Sweet

Well you never know what data is available if you don't look.

Reply to
Meat Plow

I've had that problem with these motors before. The start switch goes and makes the thing overheat and smoke. The real problem was that mine was rivited togeather, so I didn't even bother to try to fix it.

Mike

Reply to
Michael Kennedy

It's probably not fixable but knowing for sure would fix my curiosity and add to my knowledge base for future reference.

Reply to
Meat Plow

Well, it wasn't apparent at first but the switch is where the smoke came from on mine and as I said I didn't bother to disassemble it because of the rivits. Didn't seem worth the effort of grinding them out to get to a centrifugal switch that I probably can't fix.

Mike

Reply to
Michael Kennedy

I'd go with a problem in the starting circuit. If the centrifugal switch contacts stuck, the starting winding would overheat very quickly as it's not designed for continuous operation.

However, I haven't actually looked at a dryer motor in 20 years or so. I assume they are still induction motors!

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Reply to
Sam Goldwasser

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Unfortunately I have, they still have a starting winding on the one I worked on.

Reply to
hrhofmann

You're to late, you let the smoke out!... there is no hope now!

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  SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
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Reply to
Jamie

It does use that type switch, yes. I checked the pins; contacts were good; movement of switch lever was good. It could have been sporadically sticking, I suppose; I guess I'll never know, but it certainly isn't sticking now. I opened the switch assembly up and the contacts are in good shape ? I'll still burnish them to like-new condition, though.

Reply to
Ray L. Volts

Indeed, I found it impossible to squeeze any info out of GE at all on this thing ? it's got a great many sorts of identifying numbers on it, none of which GE themselves could reference. I got the entire blower for a song ? and a little bit of time as a captive audience (the guy was bored and lonely :) ? from an appliance repair shop. The shop owner couldn't tell me which dryer it came out of, so I can't go on that kind of info, either.

Reply to
Ray L. Volts

I opened this one up. In my case, no drilling or grinding was required. It was a simple matter of prying up the rivet rims with a jeweler's flat blade driver and pushing them through with an appropriate size hex driver. The switch contacts are in decent shape and the switch levers move freely (and appear to have done so all along, as it's clean around the pivot points). There's also a fairly powerful spring pushing down on the starter switch lever, ensuring disconnect ? from the compression force required (calibrated finger, admittedly), this spring seems quite adequate to break a sticking contact. I honestly can't see this switch as the culprit, but it's possible.

Reply to
Ray L. Volts

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