Help with lathe motor capacitor

Guys, I'm on with restoring a old pools 4" special lathe, the motor on it is a brooks crompton (I could just about see the sticker) but I don't know any of the spec as the sticker was very faded... Has MH097849 stamped on it

I need a start capacitor but no idea of uf rating...any idea's?

The motor is a single phase 240v

When the power is switched on, the motor hums but I needed to spin the pulley on the lathe to get it running. There is only provision for 1 capicator (ive got the cap cover and there is 2 spade end wires coming out from the motor) so i assume its a combined start/run capacitor I need?

Thanks

Is the cap body not marked?

Mark see is there's any info here link http://www.lathes.co.uk/pools/

H

You probably wouldn't go far wrong with an 8uF start capacitor from RS or Farnell

and make sure it is 400v working capacity! I agree with John 8uF will do it!

Phil

No cap fitted when I got it, spin to start !!

Thanks guys, I'll try a 8uf

Give the chaps at Power Capacitors / Trnaswave in Birmingham a call I'm sure they will advise, I had a problem with a compressor motor the makers agent wanted an eye watering sum for a replacement I think PCap charged about a fiver !

John

Is there a circuit diagram on the terminal cover. ? As has been said it MUST be 400V. There are several ways to start an induction motor, from split phase to numerous ways to use a centrifugal switch. The important thing is that the motor spins up almost instantly, if it stays on the start windings for more than a few seconds it will soon cook ! Noel.

The motor fitted looks very much like this:

Motor

The wiring is 4 wires coming from the top, only 2 were connected to the main plug so that must be the run circuit, the other 2 wires, i assume would be direction..

Once i source a cap, im i right in thinking, i will need to wire in the spare 2 wires for the direction?

There is 2 wires for the missing capacitor, ive got the cap cover.

When plugged in the motor hummed but you had to spin the pulley (in either direction) to get the lathe to turn, the guy has been using it for years like that but i dont fancy it !!

Would this be ok for a cap: Cap

Thanks

Edited By Mark H on 22/03/2021 08:02:50

Made for the job.

Now we have more of the story/history it could be that the start windings are cooked rather than just that the capacitor is missing. I would check the resistance of the windings. What letters are on the terminal plate ? If when you wire it up it spins in the wrong direction the start winding connections will need swaping over, BUT only the start. Good Luck Noel

No markings on the terminal plate, the 4 wires just come out of the motor body into the plastic housing, i'll get a pic up as it will make more sense...

Hopefully a pic of the motor...

Edited By Mark H on 22/03/2021 19:43:06

The red and black wires were connected to the mains plug, the blue/brown wasn't connected at all

Edited By Mark H on 22/03/2021 19:49:05

black and red are the correct colours for the run windings ! Blue and yellow were the normal colours for the start. In your case blue and brown. One has to assume that there is internal wiring for the centrifugal switch ! Therefore capacitor to the two spade connectors on the side - do you have the proper cover for the capacitor as the terminals will be at mains potential 240Volt. Live and neutral to red / black and blue / brown. If the direction of rotation is wrong then swap blue and brown. Good luck, Noel

Yep, i'll got the cover for the Cap

Well, this is confusing me, red/black connected, motor runs but anti clock, needs to be clockwise.

Brown/blue, I can connect to br/red and blue/black and runs anti, if I swop them, the rd trips..

If I just use red/black but swop them, motor runs anti, I can connect blue/Brown to mains and still runs anti.

Without cap I can get it to run clock if I spin the pulley, with cap connected..anti

No wire combo with cap fitted seems to get the motor to run clock only anti..

Wonder if something is knackered in the motor ??

I'm wondering because its a old motor, it only runs in one direction, thats why the cap had been removed so you could manually spin the motor clockwise to start it.....

Edited By Mark H on 27/03/2021 15:45:22

Edited By Mark H on 27/03/2021 15:48:35