Thread: Electric Motor fail

DSEL, one thing you can try is to turn it on and carefully spin the cutoff wheel in its normal direction and if it starts running up to speed and works OK, it is usually the starting capacitor has weakened. Any motor repairer can replace it.
Hope its as simple as that.
Rgds,
Crocy.

Hi, Firstly I'm NOT a sparky, I'm going from experiences. I would say that the capacitor has seen better days. Is it expensive, depends on what you call expensive, around the $20-30 mark, only 2 wires on it, may require soldering or spade fittings to connect. If you take it off yourself, get it checked out by a sparky or electrical repair place, they should have something in a similar or slightly larger microfarad. If they do it, it could be $80-100 or more. DO NOT go lower as the unit will be the same as what it is now. Before dismantling it, check it out by switching it on and trying to spin the blade fast, USE GLOVES so that you don't loose skin, if it runs, then it is definitely the capacitor.
Kryn

For cheap motor caps try Jaycar, $15 for the 6 to 30 microF range.

The other thing which wears in single phase capacitor start motors is the centrifugal cut-out switch. Both the centrifugal mechansim and the actual switch contacts. Usually, the weights just get 'stuck' open because of dirt and grime. If you decide to look further, you can take the end cap off the motor (usually the opposite end to the output shaft), after removing the fan cover and fan, you can clean up and lubricate the mechanism and confirm that it can move freely. Clean the contacts if they are open ones, with a little fine emery paper and reassemble. If the contacts were the problem, then it should start again. If it still sits there and growls, its definitely the capacitor.
It's worht checking the centrifugal mechanism in any case, because nobodey ever serivces them....

Thanks for all the tips guys. what lube should be used on the centrifugal mech?

Couldnt get the motor to turn by spinning the wheel. I undid the two bolts holding the cover on the non drive end but that wouldn't come off either. The capacitor looks easy to change but there is no markings I can see to say what it rates at. Does the motor plate provide that info?

Took the belts off and ran just the motor and it goes but not well turns slowly and with a wow-wow sound.

Joe

that's what went on my bandsaw motor a couple of years ago
the motor man (engine rewirer) said it had a lot of crap in it

more likely what is wrong with it at the moment
I need to pull it down and have a gander

cheers

DSEL

you might be able to hunt around for an engine rewirer - I found a chap in the next suburb - it was word of mouth stuff.

Originally Posted by DSEL74

Took the belts off and ran just the motor and it goes but not well turns slowly and with a wow-wow sound.

bearings?

Theres a electric motor bloke in Lilydale, I've pulled the motor off and left the wiring look attached, I guess that is the best best dropping buy and just asking the question and see what $$ he replies with.

Ok I had the motor checked out by a specialist….It isn't the cap that works fine, bearings are fine. Unfortunately it is most likely a break in one of the windings. So a new motor is required

For a 1.5Kw motor with a 1" shaft to match the pulleys, approx. $300-400 so looks like the cut off saw Granddad built will have to be retired (at least until I can find a suitable secondhand motor for cheap) and next week I'll be cutting all the 30 steel posts for the cyclone fence with an angle grinder and trying to get the ends square.

Hi Dale,

Did he say which winding was open cct, the run winding or the start winding?

If it was the start winding open cct, then it would have run normally with a kick start, if it was the run winding that was open cct, then it would have kicked and then stopped, or maybe the centrifugal switch was chopping in and out and it was just turning on the start winding alone.... that might explain the "wow wow" sound?

Did he offer to repair it? Or just give you prices on a new motor?

Ray

Has your mate offered anything towards repair or just walked away.

Ray, it just turns slowly about the same speed as if you were turning by hand, but won't gain any momentum it's a 2900rpm so it should be up and moving. he didn't really go into detail about where the break would be. said If it was the cap it would be cheap & easy fix but this wouldn't be cost effective to repair.

Pipeclay I think I'm on my own there

FYI