What causes a vacuum cleaner motor to over-heat?

Old 05-23-14, 04:24 AM
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What causes a vacuum cleaner motor to over-heat?

My Panasonic MC-E3002 upright vacuum cleaner has recently been stopping after a few minutes of vacuuming. This is due to the thermal cut-out in the motor cutting off the power. It takes over six hours for the thermal cut-out to reset itself. Then the cleaner works once more. The filters are clean, the bag is only half full of dust.

I read in a post that one cause of over-heating could be worn carbon brushes in the motor. After some helpful advice from this forum on how to get the motor cover off, I had a look at the brushes. They are in good condition, plenty of length left, and slide freely in their holders. The commutator looks reasonable.

So - what else could be causing over-heating? Any ideas? Or could the thermal cut-out be operating at too low a temperature? And if so, is it replaceable? (The service manual only gives instructions on replacing the complete motor - which costs as much as a completely new vacuum cleaner.)
Old 05-23-14, 09:26 PM
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Usually poor airflow is the cause of a thermal issue. That is a 1500 watt motor which needs a LOT of air moving across it to keep it cool. Have you felt the motor after it shuts off on thermal overload ? If it's REAL hot then the thermal breaker is probably ok and just doing its job.

As far as I can tell the manufacturer doesn't offer a replacement thermal overload switch. In the pic below I've highlighted it. If you wanted to get creative it could be replaced. You would need to get the degree rating off of it. I can look it up and you could get it.

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Old 05-24-14, 09:35 AM
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Vacuum Cleaner Overheating

Thanks for the info.

Since I stripped it down to look at the brushes, it hasn't stopped working while in use.
If it does stop in future (and if I have the time at that moment to strip it down), I'll have a feel of the motor, and note down the degree rating of the thermal overload switch.
Meanwhile .... if it ain't broke, don't fix it!
Old 05-24-14, 10:34 AM
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Poor Air Flow....

Just might be an air flow restriction some where. Maybe a restricted hepa filter??? if equipped with one. Or maybe a filter pad some where else? Below the bag or before the heppa micro filter. Maybe the hose is restricted??? Remove and check. Air intake Passages some place may be restricted.

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