[kong]

Hiya guys, I have an old motor (induction?) which is single phase, 240v (UK) and reversable. The thing is, I don't know how to wire it up! There are four terminals inside, u1 u2 v1 and v2, plus the earth. The question is, in the UK, we use live, neutral and earth, so which which pair of terminals do I use? Also, what do the letters u and v stand for? Thanks, Jason.

[Al_The_Man]

Single phase induction motors, generally have a start winding and a run winding, the start winding may, or may not require a capacitor in series with the winding and some have a centrifugal switch that cut the start winding out as soon as it is up to run.
What you have to determine is what of the above category the motor falls in. As a Guess I would say that U1 U2 is the run winding and V1 V2 are the start winding.
Reversal is achieved by reversing either pair, before start up.
In the absence of any other info, I would measure the windings and see if there is a difference, resistance wise, the higher resistance being the run winding.
If a capacitor is not required, you could simply put the U windings In parallel with the V windings apply power momentarily and see if it runs, if it just hums then you probablly require a capacitor start.
If you were to give it a spin, it should go up to speed. But It would be advisable to put a clamp-on ampmeter on one line at all times just to monitor the current.
If it runs, you can usually hear the centrifugal switch operate, this cuts the high current start windings out, otherwise the motor would burn up.
Some induction motors are made without cap. start and with the start winding in circuit in run.
Al

[kong]

Thanks Al, the motor has two capacitors on it, I assume they are wired in internally somewhere. So is this the correct wiring?

[kong]

Right then, scrap that last post, here are some piccies that may help! The motor has two capacitors, both are wired to Z2 on the terminal block. There are black leads going to Z1 and U2 on the block, and a green lead to U1. There is minimal resistance between U1 and U2, something like 2 ohms although I will check again if that is important? Any other info you may need, let me know! Thanks

[Al_The_Man]

The diagram of connection looks right to me, the U winding would be the run winding and the cap should be connected in series with the V winding, if that is in fact the start winding and if so, the resistance check across the V windings would show open, reversing would be done by keeping the connection on U1-U2 & swopping the connctions to V1 & V2.
Al

[kong]

Thanks Al, works great. You are indeed the man