Bandsaw coolant pump help

[Richard CoxParticipant @richardcox82602]

Hi all,

I have bought a Clarke bandsaw in very good condition however the coolant pump works intermittently I have ordered a capacitor for it but upon further inspection need confirmation it looks three phase as has three wires going into the motor the capacitor is connected between one phase and neutral if I’m correct aren’t capacitor that create a false three phase connected between live and third phase ?, also it works when you spin the shaft to get it going the bandsaw is 240v is this a Common thing they do with the small coolant pumps,

Rich

[Richard CoxParticipant @richardcox82602]

[Andrew TinsleyParticipant @andrewtinsley63637]

It is certainly only single phase, so more than likely the capacitor is open circuit,

Andrew.

[not done it yetParticipant @notdoneityet]

Doubtful it has a start winding, but if it does, it could be the ‘centrifugal’ switch giving trouble. Capacitors should be open circuit. They steadily lose capacitance, then/or often go short circuit and let the smoke out

[john fletcher 1Participant @johnfletcher1]

Most likely a faulty capacitor. However,some of these small motors have in effect three coils, a pair are connected in series across the 230 volt supply. the third coil is connected to the centre tap of the pair (TEE shape) and the capacitor is connected to the third coil open end. Now, one end of the two in series is connected to the second capacitor terminal and to the 230 volt supply. The other end of the pair ( second) is also connected to the 230 volt supply.The Capacitor and the third coil are in series. This means the capacitor can have a lower working voltage and be cheaper.John

[John BaronParticipant @johnbaron31275]

Hi Guys,

That motor has two similar windings, the capacitor goes across the ends the other ends are connected together and are the mains neutral connection. Depending upon which way you want it to turn the mains live is connected to one end or the other of the capacitor. There is no CF switch.

Edited to add picture.

This is the circuit except that where the CF switch is shown the capacitor goes straight to the end of the winding.  There is not a CF switch.

 

 

Edited By John Baron on 24/05/2020 22:13:01

[Richard CoxParticipant @richardcox82602]

Thanks for the replies lads, so it looks correct then that the capacitor goes from neutral to the cap then to the motor

rich

[Oven ManParticipant @ovenman]

There is a configuration known (I think) as "Steinmetz" which enables a three phase motor to be run on single phase by the addition of a capacitor. A fairly large value I think. I can't remember the exact wiring configuration, but ran my pillar drill for years with a 3 phase motor so configured before aquiring a VSD.

peter

[John BaronParticipant @johnbaron31275]

Posted by Richard Cox on 24/05/2020 22:27:53:

Thanks for the replies lads, so it looks correct then that the capacitor goes from neutral to the cap then to the motor

rich

Hi Richard,

It doesn't really matter ! Reversing the motor is simply a matter of moving the wire from one end of the capacitor to the other. In the picture I posted the neutral is assumed to be the middle wire going to the common junction of the windings.

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