I have recently refurbished a (probably 50s) 1/2 HP Metropolitan Vickers 4 pole single phase motor to replace the existing weedy Chinese motor on my belt linisher. The one I have is Capacitor start induction run. So there was/is only a single capacitor fitted. The one in mine was dead and did need replacing, but these capacitors are cheap and readily available.

Edited By Stueeee on 02/03/2022 17:16:50

Try https://www.model-engineer.co.uk/forums/postings.asp?th=103028 to see how to post – a photo of motor plate showing power etc would be a good guide – often the size of a cap is marked on these plates.

Edited By Frances IoM on 02/03/2022 20:14:46

First , Welcome to the party ! There are several options, 1 just plug it in. If the motor spins up to running speed , your laughing ! 2 it tries to go but rotates slowly, cap is below spec ! 3 It goes bang, cap short circuit or motor fault ! 2 replace cap ! 3 check motor for fault, ie short to ground, or cap replacement. If you want to replace the cap but do not know the value it may be found on the side or base as a uf value or a good multimeter will read the value assuming it has not gone off spec ! As has been said you may find the cap value on the spec plate, not so common ! If the unit has rubber covered wiring I would replace it. Good luck, come back if you have problems. Noel.

A word of warning about trying out the motor. If it has got wet or damp, do not apply power.

Dry it out for a few days in an airing cupboard or a very warm room. Motor windings do not usually show any ill effects from being wet. However a wet / damp set of windings plus power is virtually certain to permanently damage the winding insulation

Andrew.

As several readers have already said ensure the motor windings are not damp, put it in the airing cupboard for a day or two, then get your friendly electrician around with his 500 volt DC insulation tester, often known as a Megger, to carryout an insulation test. The electrician can also carry out rudimentary test on your capacitor, by charging it up and leave it for half an hour, he will know what to do. If all is well, leave things alone regarding dismantling.it easy to dismantle a motor and break a winding lead, but its not so easy to reassemble without scratching the insulation varnish off some of the winding. Two drops of oil is that is needed in those oil caps. I've fixed lots of good but messed up motors by people with good intensions. Regarding perished rubber, carefully disconnect the capacitor noting where the two leads come from (take a picture) then slide some heat shrink, fibre glass or other sleeve over the rubber. That motor is more than 60 years old. if all was well regarding the cap and motor insulation test then give it a run. I don't know where you but I could fix it for you and show you the future. John

A low risk way to test a motor like this after doing the basic checks is to connect it in series with an old fashioned quartz halogen security light, assuming you can find one. A 500 watt 230V mains lamp will reach 125 ohms when hot, but start at 12 ohms or so when cold. If the motor (without mechanical load) is OK, it will run, and the lamp will not light up much. If the motor does not run, the lamp will light fully, and the current will be limited to less than 2 amps.