compressor failure

[linbill]

Hi all,

I am facing failure of copeland compressor.The actual problem is compressor can't run.We startup unit,compressor drawn high amp and suddenly changed 0 ampere but the power supply was ok when i measured the compressor terminal.Therefore, I off the unit and measured the resistance of compressor.The value of 3phase wdg: is same, no open circuit.I checked the schematic dwg, never saw the internal protector.Several time I tried to run the compressor but can't start.Can anyone help me why compressor can't start above condition.
I understand wheteher open or short circuit compressor can't start.My chiller is 208-230Vac,5oHz,3phase neslab recirculating chiller.
Compressor model is REY3-0175-TFC-201 Reciprocating Copeland Compressor.Onemore anyone can share me this compressor technical specification.

Thks,
Bill

[Actinide]

How is the chiller wire up?

DOL? Star / Delta?

[coolerboy]

there could be a few reasons why the compressor fails to start.....

first off.... have you checked that the starting capacitor isnt faulty? when you check it...please make sure that it is discharged!!!!

secondly... check the resistance between the phases, it shouldnt be more than 0.8 ohm.

also, you could have a faulty thermal protect switch.

another possible cause could be the start relay... its a big relay that sits adjacent to the two caps.

ciao

[Electrocoolman]

Bill,
Sounds as if you might be missing a phase. Trying to start on 2 phases will cause high current to be drawn.

Check the fuses, and then all the contactor poles individually. You might have bad contacts.

Motor could have internal protector.

ECM

[Tesla]

Hi Bill
Sounds like a tricky one. Not sure if your working on a semi or hermetic. If its a hermetic some have thermal protection in the windings and can take 4 - 6 hours to cool to reset, it pays to remove power to ccheat to cool. When comp starts and then draws no current the cct must have opened. If a thermal safety is fitted it could be tripping when trying to start then reseting before you measure the resistance. Check for voltage at comp terminals - if there is voltage and no current the comp is open cct, either winding or safety.

[noushad123]

hi bill
i heard 208-230Vac,5oHz,3phase this voltage only in Europe
can you tell me your chiller model no and this problem is
Just know started or after replace the compressor

[Solair]

Very interesting.

[nestor_greg1220]

Hi Bill,
did the overload relay trip when the current increase? are you referring with the DWM type copeland?normally as long as your power supply is okay as three phase it has to work.is it a direct start or a part winding start?try to disconnect the wire on the load side of the conttactor and measure the voltage if you have a healthy power supply. i pressume that you have a complete three phase supply going to your load.

Nestor_greg1220

[linbill]

Hi buddy,

Thank for all, assisted me.Now the problem was found out, actually the current protective device was open.
Yesterday i tested agian, compressor still can't start
I run the unit a few minute and take off the power supply, measured the resistance of winding.The value of each winding is zero means no continuity.Afterthat a few minutes i measured again, saw the resistance vaue.Anyone can tell me why the current protective device is open.

Farewell,
have a nice day,
bill

[weeksy]

Hi again Linbill....

I just answered your other query....which is now redundant info as you've found the problem.

The protection device is for over-current & also over-temperature.
This device will open & then re-set automatically when it cools down.
It will trip due to:
a) The start capacitor is duff.
b) The compressor is seized.
c) The compressor is running too hot.

If its too hot, check the condenser, fan motor & make sure the power supply is correct.

regards

weeksy