Need help wiring up this motor

vegard · May 17, 2008

Hi,
I have a vaccum pump that I want to use for vacuum bagging carbon fiber parts. I cant figure out how to wire it. It is a compton compressor, and I couldnt find any info about it online.
The following is copied off the data sticker on the motor:

Type BCC/2508
V. 115/230
Ph. 1 A. 3.6/1.8
Hz. 50 Wo. 250
RPM 1425
Ins Cl. B BS Frame
Rtg.CONT
Cat. No. D64926 (WS)

It has 4 wires coming out of the motor housing: black, white, brown, and red.

Thanks in advance.

- Vegard

minder · May 17, 2008

Sure it not a Brook CROMPTON motor?
If so you should be able to get the info easily from them.
M.

vegard · May 17, 2008

It does not say crompton on it anywhere. I see the following labels:
compton
compton compressor Made in England
GEC small machines ltd

minder · May 17, 2008

I guess the contact would be here as a last resort.
http://www.dmd.org.uk/compt.htm
M.

vegard · May 17, 2008

sent them an email

Thanks for that link, I will contact them on monday if I cant get this resolved.
I tore the motor open. I am not an expert, but I will describe where each wire goes:

Brown wire: goes to a junction board where it splits, and both wires (one brown and one blue go into the windings

Black wire: Goes straight into the windings

Red wire: straight into the windings

White wire: goes to a junction pin. The first wire of the pin goes into the windings. One wire off that junction feeds the caps in series (one single cap, one double cap(three wires) One wire comes out of the double cap and goes through an rpm switch and back to same pin. The last wire out of the double cap goes to a dead end terminal.

Also, on the junction board, the pins are labeled: T1, T2, A1, A2, T3, T4

Thanks in advance for any help.

- Vegard

vegard · May 17, 2008

I should mention that nothing is connected to T1 or T4.

- Vegard

vegard · Sep 18, 2008

Bringing back an old thread... but I tried to get this pump running again today.
I reassembled it and just tried to give it power.

It has a black, a brown, a red and white wire.
I connected as follows (i didnt try to connect to pairs of wires) 120v:

Hot-------Neutral---------- Result
brown-----white---------- motor spins, but gets hot, runs 1425 rpm
black-------red--------------motor spins but gets hot runs about 1700 rpm
brown-------red--------------nothing
black------- white -----------nothing

Anyone know how this stuff should go?

- vegard

mfisher · Sep 19, 2008

It looks like the motor tag says 50 Hz. I think that is a problem to start, assuming that you are in Maryland. Running that on 60Hz could burn it pretty quick, especially since it is a one phase.

Just my 2 cents.

macplus · Sep 19, 2008

Can you take a picture of the winding showing all the connections. A 50hz motor can run on 60hz, most of the time you just derate the service factor ( example SF of 1.15 to a derated SF of 1.00 ), the rpm will increase by 1.2. The problem that you might run into is the pump might not be designed for the higher rpm, which could lead to pump failure.

vegard · Sep 19, 2008

I would rather not open the motor again because it has a centrifugal start switch and is very difficult to disassemble and reassemble. Can you make an educated guess to how the wiring should be done? Im guessing some of the 4 wires should be connected together. Also, Im not 100% sure of the RPM numbers that I gave earlier, if thats important.

If I really need to take it apart again, I will do it, but I would like to avoid if possible. Perhaps I can give some resistances or something that might help?

Thanks.

- Vegard

macplus · Sep 19, 2008

Without a picture, I would need to know the ohm readings between the wire's

macplus · Sep 19, 2008

Since it is a dual voltage motor, but with only 4 leads. I would have to think this motor is not reversable( start winding is 115volts, wired in parrallel with one side of the run winding ). For a 115vac, you would need a 2 circuit connection...L1= black,white L2= red, brown or L1= black, brown L2=red, white.

vegard · Sep 23, 2008

macplus,
I borrowed a multimeter today to get some values:
I dont think that these ohm values will help, but here they are:
white to brown 5.3 ohms
red to black 5.0 ohms
The rest are all infinity (tried every combination)

Should I just hook the two pairs together and try it?

Thanks, you are really helpful.

- Vegard

JunkyardJ · Sep 23, 2008

Actually, it might be reversable.

My GUESS would be to put red and white together. Then black and brown. I'm not absolutely sure about that, but I've run into a similar motor config, but the brown was blue. To reverse it, you'd switch the red and blue leads. I really don't know if it will work. :confused:

macplus · Sep 23, 2008

Hi
Right now that is what I would do, keep me posted

macplus · Sep 23, 2008

Hi
Right now that is what I would do, keep me posted. Since it is a dual-voltage motor with only four leads coming out to the junction box, it can not be a reversable motor.

vegard · Sep 23, 2008

tried it with black and brown as hot and red and white as neutral. It runs smooth, but gets hot in about 40 seconds. That seems unreasonable for a continuous duty motor. Also, it runs right at 1725 RPM.
I am thinking that I messed up the centrifugal switch when I had it apart. If the start circuit stayed on, would it cause it to heat up like this?
Or should I try the other combination of wires?

Thanks.

- Vegard

macplus · Sep 23, 2008

ok...you could try L1= black,white L2= red, brown , is your start cap mounted external. If it is, you can remove a wire off the start cap after your motor is up to speed, as this would remove the starting winding from the circuit ( your start winding, start switch contact and start capacitor are in series with one another ).
If are right about the governor switch, if the switch does not open up you would then draw excessive current ( from the start winding ), this would cause your motor to heat up.

JunkyardJ · Sep 23, 2008

It almost looks like there's a schematic on it.

Can you post a good legible pic of the label?? Is there anything there you haven't given us?

Another thought is if you just hooked one of the brown or white wires up. Try red and black to your 120v leads, and hook either the brown, or white wires to the black or red. That might be it. :confused:

vegard · Sep 23, 2008

I think I have it figured out. The start circuit was staying on. I fixed that. Now it runs cool and smooth. I still have the same wires hooked together as before. I get about 1900rpm, and about 1800 pulling max vacuum. I think its good to go. the only thing is the rpms don't match the label. As far as the information above, it is verbatim from the label with nothing left out.

- Vegard

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