Motor problem

[p0689109]

I managed to pick up a pump,motor,guard and pulleys at an auction. Its a good sized pump and a hefty motor. There are no data plates on either so i do not know the size/output figures. I thought I would check the motor out so I connected it with a plug and cable and plugged it in to see if it worked. The cb tripped. So I set about doing basic checks(I am not an electrician but am an ex aircraft engineer and so have a working basic knowledge of the mysterious force). I first checked the capacitors using a multi meter IAW a procedure I found on google. Basically it said to select a high resistance range then connect the leads and if the caps are ok you should see the meter rising towards infinity as the caps charge from the meters battery. They both did. Ones a start cap and one is the main cap. (One of the attached photos shows the wiring setup on the electrical boxes cover.) The next thing I did was remove the caps and links which allow the rotation to be changed so that all I had to play with was the terminal block with the 6 connections. 2 each of red, yellow and blue wires. I then did a continuity check first of each coloured pair. They all showed a circuit. I then checked each post against all other posts. The wires connected to the terminals marked z1 and u1 showed continuity. In my mind this is wrong and is causing my problem but IS IT?? Terminal z1 has a yellow wire to it and terminal u1 has a red wire to it.
Can anybody steer me on the correct path?
Regards, Michael T

 

[p0689109]

Motor windings.

Also can anybody identify the make and size of the pump?

 

[tigler]

Thats a Fiac twin cylinder pump, the drive motor is usually 3hp, you'll have about 14CFM FAD.
Somebody will probably beat me to it but I'll study the motor wiring and reply later.

 

[penfold]

Stator is banjoed if z coil is shorting to u coil; it may be worth having it apart for a look, but if it's in the stator assembly it's scrap(or a rewind).

 

[Justme]

Did you remove the jumper links before testing or remove the wires from the terminals?

 

[rtbcomp]

The cb tripped.

MCB (over-current) or RCD (earth fault)?

 

[tigler]

I was also thinking that was most likely.
Just a note on that method of cap test, they can seem to be ok with that test but may breakdown in use due to leakage at high voltage. The only proper way to test them is with a high voltage source. They may well be fine of course.

 

[eil]

Z1 + Z2 would normally be the start winding and U1 + U2 would be the run windings, confirm this by checking the resistance between them the start winding will have the higher resistance.

As Penfold said you shouldn't have continuity between Z1 and U1.

 

[p0689109]

Motor windings

Many thanks for your replies gents.
Penfold; thats what I was suspecting!
Justme: I had the links removed so that all I had were the terminal block each with its own feed. I did not take any resistance values, just checked for continuity. I will check the resistance values later today.
rbtcomp: The rcd tripped on the feed box.
tigler; I thought the same as you as for checking the caps but do not have the gear to fully check them. Their casings are plastic and show no signs of leaking or swelling.
eil: what are the v1 & v2 windings for then if the other two are for run and start?
tigler: Many thanks for the identification of the pump. I was hoping the motor worked so that I could check the pump worked. It sounds like it is trying to pump when you turn it by hand but that is no good. How do these pumps work as far as the valve(hic) mechanism works and is it a big job stripping it down to check whatever does that job(reed switches/)Is there gaskets or the like involved?
Thanks again gents. Sorry for the saga.
Regards, Michael

 

[tigler]

The valves are stainless reed or finger valves. They are mounted on the underside of the head and are easily cleaned or changed. From memory, head gasket is copper, so could be re-used by annealing before re-assembly. Not a bad pump, the vital thing is oil, grade ISO68 or SAE 20 compressor oil. Don't use motor oil, it will foam and is too viscous. Change it every 6 months regardless, unless it's used 8 hrs a day, 5 days a week, then change it every 300 hours.

 

[rtbcomp]

If it's the RCD then you have a short to earth, this needs sorting before you play around with the links.

 

[p0689109]

Fiac pump

Thanks for that tigler. Any idea of torque settings for the head bolts and of a supplier for the gasket?
Regards, Michael T

 

[eil]

V1 V2 would be your centrifugal switch, which you should have continuity through at rest.

 

[p0689109]

Motor windings

Thanks for the quick replies. Is there any tricks, precautions or traps to be wary of on stripping these type of motors for inspection I should be aware of?
Regards, Michael T

 

[eil]

Check if you have continuity between the motor body and the windings.

 

[p0689109]

Motor windings

I will do that, thanks eil.
Regards,Michael T

 

[tigler]

Thanks for that tigler. Any idea of torque settings for the head bolts and of a supplier for the gasket?
Regards, Michael T

No but it's not critical, just a nice nip. If a gasket is needed for some reason it would have to be from the UK importer, they are in Manchester.

 

[p0689109]

Motor windings

Thanks for that tigler. I was a bit worried it being ali.
eli: I have taken the resistance values and they are :- loop u1/u2 2.7 ohm
loop v1/v2 0.9 ohm, loop z1/z2 3,5 ohm,
Resistance values to earth of each terminal are as follows:- u1 3.3 ohm, u2 1.5 ohm, v1 & v2 gave no reading (i.e. infinity), z1 1.0 ohm, z2 4.0 ohm.
Regards, Michael T

 

[madkayaker]

That's a three phase motor with capacitors to create a phase difference for the third winding. Connect it up as per the diagram on the back of the lid

 

[madkayaker]

Don't for get you need to use links to short out the windings as well again same as diagram