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Window Fan


Active Member
Not exactly high tech electronics. Just an electrical problem. I have a couple of window fans. Dual fan type, roughly similar to the picture.WindowFan.jpg
One of the units has two speed fans, and the motors each have six wires. The other unit has three speed fans, and the motors have eight wires each. Both units have a reversing switch. The wiring is a rats nest. I can trace the wiring that's external to the motors, but that doesn't really tell me much when I don't know how the motors themselves are configured internally. I've spent hours searching the net trying to find a plausible wiring diagram for the motors, with no luck. Does anyone here have any experience with these small multi-speed motors, and know how they are wired internally?

The problem:

Unit 1 (2 speed reversing fans):
One fan works fine. The other one turns, but torque is very low and so it won't get up to speed. I suspected a bad run cap, and swapped in another one, but it didn't help.

Unit 2 (3 speed reversing fans):
Was working fine, and then I heard a snap, and it quit. Neither fan operates, and no sign of any failed component. Admittedly I haven't spent much time trying to track down the cause of failure. It must be a component common to both fans, which would limit it to the speed switch or the reversing switch.


Active Member
Another thought just occurred to me. There's probably a thermal overload cutout embedded in the motor windings. If those leads are brought outside of the motor, that would account for one pair of wires. And if the cutouts for both motors are wired in series, it would explain why both fans in Unit #2 quit at the same time.


New Member
Do you have some pictures? Every motor should have specifications on it, that way you might find the connection schematics


Well-Known Member
unit 1) clean?
unit2) track error with ohm meter, u r on right track whether its fuse or failed component

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