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aded pole induction motor (AC)

gatewood

New Member
Hey guys! first post here (sorry if this is the wrong section for this thread)

I came across a broken fan that uses this kind of motor to spin the blades, Ive tested the whole wiring and the motor is the one to blame.

https://en.wikipedia.org/wiki/Shaded-pole_motor

So my question is this, given the simplest kind of AC motor, anyone knows the common causes of failure?
 

MaxHeadRoom78

Well-Known Member
That is a simple shaded pole induction motor.
Have you measure the winding for continuity?
Usually the sintered bronze bearings dry and seize and/or the motor overheats and burns out as a result.
(Not really Automotive!)
Max.
 

unclejed613

Well-Known Member
Most Helpful Member
there should be continuity across the winding.... there's not a lot here that can go wrong, the winding could be open circuit, or there could be a thermal fuse in series with the winding that's open circuit. make sure the shaft turns freely. clean the gunk out of the bushings, and soak them in automotive motor oil. the idea is to get the sintered brass to absorb some of the oil. thin oils like WD-40 are good for unfreezing stuff, but it's too thin and too volatile to use as lubrication in the long term. i would recommend getting a synthetic motor oil with teflon. that stuff can be very useful, and goes a long way.
 

rjenkinsgb

Active Member
Just on the offchance..

If the winding are OK and it spins freely but still does not run:
The "shading bands" - the thick copper loops around certain parts of the laminations - can crack over time in some types of shaded pole motor.

When they do, the rotational effect of the magnetic field is reduced or lost, so the motor will not run properly.

If there are any cracked bands you may be able to replace them by filling the same space with as many turns of _bare_ copper wire as will fit. The idea is to create a thick, single, "shorted turn" capable of handling relatively high currents, so the individual turns of copper need to be tight against each other.
 

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