It's a synchronous 240v ac fan . There's a 1.5uF 450V cap inside, a fwd/reverse switch and a 3 speed switch. When I turn it on, it hums slightly. It won't go even if I spin the rotor. Is the most likely fault the cap? The fan lasted 2 days before failing. I can't get inside the motor to see if there's anything else that could be faulty. Any clues?
"The fan lasted 2 days before failing"
take it back then, get another one
martin
In message , dated Mon, 7 Aug
2006, martin.shoebridge writesYes, the cap is a prime suspect. Take the fan back under guarantee.
-- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
I concur with the others - it's broken, take it back.
But, if it didn't even spin after you "helped" it, then it's not the capacitor. We did this experiment in High School Physics last century, and if the windings of an induction motor are intact, it _will_ spin without the cap - it's just that it has to be hand-started, and the rotor has to catch up with the reversals of the magnetic field.
Cheers! Rich
In message , dated Mon, 7 Aug 2006, Rich Grise writes
That worked for your motor but it doesn't necessarily work for all modern motors. No, I don't know why.
-- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
It might not work for a high RPM motor. The start circuit has to cut out at something like 25% of operating speed. But I'd expect a ceiling fan to be rather easy to hand start.
I burned out the start cap. in my pressure washer. I could still start it by giving the entire unit a sharp twist about half the time.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ There are only 10 kinds of people in this world, those who understand binary and those who don\'t.
Quickly. Before the three day warrantee expires.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Human beings were created by water to transport it uphill.
These motors are not synchronous, just permanent split capacitor motors. And yes, the phase shifting caps open, rendering the motor a hummer only. Usually cheap ass Chinese capacitors - price point items. No amount of spinning will get this puppy going. Only cure is a trip to the store for an exchange. I see why you want to fix it though - it's a bear to take the damn thing down and rebox it! regards, Tom
bullshit. (most unlikely to be synchronous)
sounds like it.
the capacitor should be fairly cheap to replace, but get one that meats the relevant safety rules.
Bye. Jasen
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