I have a GE 1/2hp motor I bought at a charity auction. It had been donated by a close friend who said it was almost new and came from an attic fan. He had bought the fan and replaced the motor with a bigger and faster rpm motor. This one runs at 1075 and is the perfect wax buffer. The question, it is thermally controlled. When I buff a pipe the motor will overheat and shut down after 15-20 minutes. As soon as it cools off it will come back on. On the plate it says Time Rating: Continuous Air Over. Does this mean I need to mount an external fan? I suppose in its original configuration the attic fan provided cooling for the motor. Or could it be a motor problem?
bob gilbert
Motor Question?
- staffwalker
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Could be a problem with the motor... Is there any place on the shaft for a fan to mount? A lot of motors have a shaft sticking out of both ends of the armature, one takes the belt or whatever, and one takes a fan (usually in some kind of shroud). If that fan is missing, a motor will overheat surprisingly fast.
- staffwalker
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No, there is no place to mount a fan it's only a single short shaft. I am assuming if the motor was designed to be air cooled it was cooled by the attic fan. This motor came out of a large 48" attic fan. Fans I have seen have the motor mounted in the housing. The fan running would have pulled air over the motor.
I'll have to get a fan and run some tests. Just thought some of you 'motor' folks might know if certain motors were designed to only work with air cooling. Thanks for the answer.
bob gilbert
I'll have to get a fan and run some tests. Just thought some of you 'motor' folks might know if certain motors were designed to only work with air cooling. Thanks for the answer.
bob gilbert
- KurtHuhn
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Yes - that rating is a standard in motors. Most electric motors carry a duty rating, some carry a duty with qualifications. Continuous Air Over is one such qualification - it is rated as continuous, but only so long as there is constant air movement through the windings. Most electric motors in use on equipment or as buffers are rated based on the internal (or externally attached) fan. This where things like TEFC (Totally Enclosed Fan Cooled) enclosures come in.
For a motor designed to drive a fan, there is no internal fan to cool the windings - it would be extraneous since the fan would provide more than enough cooling air movement. Using that motor for something else, with no attached fan, would almost certainly trip the thermal protection. My guess is that the enclosure type is "Totally Enclosed, Air Over", or TEAO - these are very, very common in HVAC and ventilation uses.
It may be possible to modify the motor with a small external fan housing on the back.
For a motor designed to drive a fan, there is no internal fan to cool the windings - it would be extraneous since the fan would provide more than enough cooling air movement. Using that motor for something else, with no attached fan, would almost certainly trip the thermal protection. My guess is that the enclosure type is "Totally Enclosed, Air Over", or TEAO - these are very, very common in HVAC and ventilation uses.
It may be possible to modify the motor with a small external fan housing on the back.
Frank - Some of us have a condition known as cobbleritis. That's when a guy will spend six hours in the shop and make two trips to the hardware store to spend $53 buying bushings, all-thread, hose clamps, angle iron & rubber washers in order to convert a free motor into a buffer he could have bought for $60. It's most prevalent in people from Arkansas.
"Cut your own wood and you warm yourself twice." - Henry Ford
I know that only too well. I used to make electronic gizmos at home, then install them in homemade wooden boxes, rather than buy metal or plastic boxes. Some of my junk were right old Heath-Robinson affairs.FredS wrote:Frank - Some of us have a condition known as cobbleritis.
Regards,
Frank.
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Grouch Happens!
People usually get the gods they deserve - Terry Pratchett
Frank.
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Grouch Happens!
People usually get the gods they deserve - Terry Pratchett
- staffwalker
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