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Louis Brandt
07-01-2009, 7:24 PM
Hello,

I have a large box fan (about a 30 inch model) that I use in the garage. This is a really large box fan, not one of the small cheap ones.

A few days ago, it would only run at two speeds, then a couple days later at only one speed. Now, it won’t run at all.

I’m not much of an electrician. Does this sound like a bad switch, or does it sound like the motor has gone? And is there an easy way to test the switch? And is the switch easy to replace?

Thanks,
Louis

Russ Filtz
07-02-2009, 7:34 AM
Try to find some exposed ends of the wires and an Ohmmeter? Does the motor hum a little when trying to turn on? I had an old fan and the bearings gummed up over time. Would hum and try to turn (and hopefully not catch fire!) until the gummy bearing heated up enough to move! May be time to disassemble, inspect, clean, and reassemble, hopefully with no spare or broken parts!

Rod Sheridan
07-02-2009, 8:40 AM
Louis, can you turn the blade easily?

I'd start with making sure the bearings aren't seized.

Regards, Rod.

Louis Brandt
07-02-2009, 9:28 AM
Yes, the blade turns ok. No hum or any kind of noise.
Louis

Rod Sheridan
07-02-2009, 9:37 AM
Hi Louis, the switch should be easy to check with an ohmmeter.

One wire from the line cord will go to the switch, this is the common terminal.

Unplug the fan and mark the motor wires that go to the switch.

Remove the motor wires and using the ohmmeter measure from the common switch terminal, to the other terminals on the switch.

Each terminal should be connected to the common terminal at one speed setting of the switch. (The ohmmeter should indicate near zero ohms resistance.)

If the switch doesn't connect to the terminals at some switch setting it isn't working.

Also while the motor is disconnected from the switch, you can measure from the common motor wire (still connected to the line cord, to each of the motor wires you removed from the switch.

Each winding should have a resistance, perhaps 10 to 40 ohms?

Regards, Rod.