240v induction motors.

What exactly is the problem? If it won't start then the fault usually lies with the start capacitor. Small motors are capacitor start and run, ie the start capacitor remains in circuit all the time, extractor fans or central heating pumps fall into this category. Larger ones are capacitor start, ie the capacitor is switched out of circuit once the motor gets up to speed.
 
It's on a Clarke pillar drill. It was working OK, but the motor was hot to the touch. Then there was a distinct change in the sound of the motor. After it was switched off, on the next restart instead of starting at normal speed, it started slowly, building up speed over the first few seconds. After that the motor, particularly what I think would be the capacitor covers, got really hot.
 
Hi Harvey,
I phoned clarkes tech department when i had a problem with my compressor motor,found them helpful.
Clive..
 
I may well give them a call then.

I was just hoping there was a whizkid on here that could tell me exactly what the problem was, 'cos I haven't got a clue, apart from what I've googled, and that hasn't helped a lot.
 
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Sounds like a faulty capacitor, however once up to speed they are generally ok though if the capacitor is dodgy they can lack torque.

Graeme
 
Sounds as if the capacitor is not being switched out of circuit when the motor is up to speed if it is a capacitor start type. This is accomplished either by a centrifugal switch or by a relay. If it is a switch you can often dismantle and clean them. The capacitor may have been damaged by being left in circuit so will have to be replaced. If it is a capacitor start and run motor then there will be no switch or relay so just replace the capacitor. Clarke's should be able to advise you and supply any parts.
 
Sounds like the cap is going bad. Unplug the cord, whip the cover off to gain access to it.
Remove it and go to your local supplier with the specs of the motor for a replacement.
 
It has two caps, a start and a run. As it still satrts but runs slowly I'm guessing the start cap is OK, and the run cap is faulty, as from what I've read faulty run caps make the motor run slow and overheat, which is my problem exactly. I have the values for both, and I did read how you work out which was which, once I read that again I'll take it out and have a look at it. I'm hoping it has a discharge resistor on it so I don't electrocute myself.....

I also read that capacitors can go out of range over time so I'm hoping that's what has happened.

I did phone Clarke Technical, and as nice as the bloke was, trying to be helpful, he didn't really know as much as I did already, which wasn't a lot.
 
Just as a follow up, I bought a run cap from Hong Kong (ie China) through ebay, a favourable change in the exchange rate between when I saw it and when I bought it dropping the price from £2.01 to £1.88 including shipping made it well worth taking a chance as the one that failed was Chinese and that lasted over 10 years. It took about a fortnight to arrive, but there was no rush. I fitted it this morning, and after just a short no load test run the motor doesn't seem to be getting anywhere near as hot as it was, just barely warm to the touch, so I'm hopeful it will be OK the next time I come to use it. Thanks for all the input.
 
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