Compressor electrical wiring problems

[David2005]

Sorry about all the pictures.
What happened was the motor was rebuilt by a place and for some reason they changed around the wiring. I took note of how to put it back together but not too confident wiring it up now they changed it around. I have an idea but not brave enough to waste a brand new motor

Basically I just want to know where to put the blue and the brown wires that come from the mains??????????

If you can't see from the photos this is where the wires are going.
Two black wires and two red wires come from the motor. One of the black wires join to a red wire and this then is the red wire going to the reset switch.
The other red and black wires coming from the motor go to the wiring block.
The two white wires come from the wiring block and go to the caps.
The other blue wire coming from the wiring block goes to the reset switch.

 

[ilovemygt35r]

bloody hell cant see whats really going on there, maby if you draw it as a circuit diagram maby someone might commit, did you get your motor re-wound?

 

[the snooper]

looks like blue to blue to me as it connects the the overload cutout and at a guess the other to the post with the othe loose nut

 

[David2005]

Yes mate got it rewound. I dunno why they couldn't just wire it the same as before.
I did a drawing in paint if its any good

Looks like blue to blue to me too and brown to the wiring block where the black and white are connected. I wouldn't trust loose nuts as they changed it all.
If someone whos certain could let me know?

Edit: Actually it definately has to be like that doesn't it?

 

[eil]

Looks like they have added the red wire with the spade on the bottom of the overload and a screw on connector on the other end for the windings, It looks to have two caps but only one connected is that right ?. what are the values of the caps as I cant tell if its cap start cap run motor or PSC motor.

 

[jasonmcc]

Looks like your mains go on the blue and black on the terminal block, they have put sleeving on the other terminals so you don't use them. If your not sure ring them and ask them if they use black leads on the Run Winding. If they say yes then Black and Blue are the correct leads.

PS I know that this my first post but winding motors is my job and i think that the fact they didn't do it the same or give you a drawing is poor. Best of luck.. Jason.

 

[jasonmcc]

Looks like they have added the red wire with the spade on the bottom of the overload and a screw on connector on the other end for the windings, It looks to have two caps but only one connected is that right ?. what are the values of the caps as I cant tell if its cap start cap run motor or PSC motor.

Hard to see but it looks like two capacitors wired in parrallel, so the motor is a permanent capacitor type. Both should be rated near 400-450 V

 

[eil]

Hard to see but it looks like two capacitors wired in parrallel, so the motor is a permanent capacitor type. Both should be rated near 400-450 V

Does look like it, as you say not very helpful not scribbling down any instructions for him. Welcome to the site Jason

 

[David2005]

The two white wires go to the first cap and then two more wires go from the first cap to the second, so that is parallel isn't it?

Actually thats another question, they gave me two smaller caps back with the motor than the ones that were used first day. Can I use either? Are the smaller set to suit the rewound motor?

 

[David2005]

Does look like it, as you say not very helpful not scribbling down any instructions for him. Welcome to the site Jason

Well they left a tag on the motor saying "to reverse the motor swop the two black wires"

 

[jasonmcc]

Yes that is Parrallel, it doesn't matter if they are physically smaller as long as they have the same value, Should have something on the side that says uf (microfarad) that is the value. They may have changed them as they may have been the cause of the motor to burn out.

 

[David2005]

Yes that is Parrallel, it doesn't matter if they are physically smaller as long as they have the same value, Should have something on the side that says uf (microfarad) that is the value. They may have changed them as they may have been the cause of the motor to burn out.

Ya they replaced them with smaller ones, I'll run out and get the specs

Edit: The original ones are 60+65uf and the ones that they gave me are 30+40uf

 

[jasonmcc]

If you have a multimeter check the resistance across the two red leads and the two black leads from inside the motor. ( you need to disconnect them from the other terminals first ) 99% of the time the lower resistance is the run winding.

 

[jasonmcc]

Ya they replaced them with smaller ones, I'll run out and get the specs

Edit: The original ones are 60+65uf and the ones that they gave me are 30+40uf

Do not switch this motor on. The capacitor value gives you the correct starting torque and limits the current through the starting winding. The incorrect vales will burn the motor out again. the only time I have ever altered the capacitor size on a motor is when it has its voltage converted. EG 110V to 240V. Take it back to the Repair shop and ask them if they load tested it. chances are they will have to say no. not many rewind shops have load testing equipment ( We Dont ). If possible take the Commpressor with you and ask them to connect it and run it up to full pressure checking the motor current as well.

If the motor fails to start or trips the overload out they may well have done somethig wrong, and they should put this right.

Also check that the motor will cut in again when the pressure drops.

 

[eil]

Does it have the cap values on the motor rating plate by any chance, have you owned the compressor for quite a long time or just bought it.

 

[David2005]

Do not switch this motor on. The capacitor value gives you the correct starting torque and limits the current through the starting winding. The incorrect vales will burn the motor out again. the only time I have ever altered the capacitor size on a motor is when it has its voltage converted. EG 110V to 240V. Take it back to the Repair shop and ask them if they load tested it. chances are they will have to say no. not many rewind shops have load testing equipment ( We Dont ). If possible take the Commpressor with you and ask them to connect it and run it up to full pressure checking the motor current as well.

If the motor fails to start or trips the overload out they may well have done somethig wrong, and they should put this right.

Also check that the motor will cut in again when the pressure drops.

I don't know anything about rewinding motors but surely its just done to the same spec and therefore the original caps should work?
I have no idea why they would give me smaller caps, I actually didn't give any in with the motor when it was being fixed.

I've owned the compressor for around 3/4 years

 

[jasonmcc]

When you rewind a motor you take out the old winding counting the turns wire size etc. then you put new wire in to the same turns, size etc. The capacitor value is unfortunatley not always marked on the motor plate, so it sounds like the repair shop have used an educated guess and put on capacitors that will probably get the motor running off load, but not always on load. If the 60+65uf caps are the originals take them to the rewind shop and ask them to check them, If they are good use them if not ask them for new caps of the correct value.

Best practice I find with motors is to take the whole motor in so that it can all be checked and run as a complete unit, so that when it is returned to the customer you know that it is going to work and last.

Capacitors can "break down" with age and use, and can appear to be ok. So what looks like a nearly new 60uf may only read 40uf.

 

[David2005]

When you rewind a motor you take out the old winding counting the turns wire size etc. then you put new wire in to the same turns, size etc. The capacitor value is unfortunatley not always marked on the motor plate, so it sounds like the repair shop have used an educated guess and put on capacitors that will probably get the motor running off load, but not always on load. If the 60+65uf caps are the originals take them to the rewind shop and ask them to check them, If they are good use them if not ask them for new caps of the correct value.

Best practice I find with motors is to take the whole motor in so that it can all be checked and run as a complete unit, so that when it is returned to the customer you know that it is going to work and last.

Capacitors can "break down" with age and use, and can appear to be ok. So what looks like a nearly new 60uf may only read 40uf.

I had them checked by a friend of mine and he said they were grand. I was going to use them instead of the smaller ones anyway.
I didn't take in the caps with the motor because I thought they wouldn't need them and they never asked so I thought it was fine.

I think I might call into see them and check it out. I was waiting 8 months for them to do it in the first place, granted I wasn't in a rush but thats a pretty poor turnaround.

Thanks for all your help

 

[the snooper]

8 months id have been there got it back and took it somewhere else

 

[brightspark]

how much did it cost >? u can get a new 3hp motor for 90 quid