Compressor thermostat failure

[Rickspain]

I was recently called out to an Air-Con that was constantly tripping the earth leakage mains supply as soon as the compressor was energised. Since it was under guarantee, I merely assertained where the fault lie before calling the company from where purchased. Disconnecting the earth wire allowed the system to operate correctly. Further investigation showed a low resistance to earth on the compressor leads.
The company engineers discovered a failure of the compressor thermostat. Can anyone show me a picture of where this is located - it appeared to be within the compressor itself. - Ricardo

[The Viking]

I was recently called out to an Air-Con that was constantly tripping the earth leakage mains supply as soon as the compressor was energised.

No compressor should be fed from an RCD protected circuit. RCDs will trip even when the compressors are running as designed.

The company engineers discovered a failure of the compressor thermostat. Can anyone show me a picture of where this is located - it appeared to be within the compressor itself. - Ricardo

It could be internal, more likely it's fitted inside the compressor's terminal box (It's the little round black thingie)

[Brian_UK]

I think that you were being blindsided.

Internal motor protectors do not fail to earth they simply go open circuit when overloaded or overheated.

If the compressor was running and the amperage was within range then yes then windings were possibly at fault but the real fault was connecting the aircon to an earth leakage protection circuit.

[Grizzly]

Care to explain then why thousands of fridges, freezers and air conditioners run happily on RCD's?

Not all inverters trip either. Two brand new J series fed from same c/u etc one ran sweet the other tripped the board. Only solution was to change RCD for a switch. Either way, it does show not all inverters will trip all RCD's

jollycold.
In the UK we do have a problem with A/C units on rcd protected ciruits and nuicence trips.
wether it's as simple a difference as we are 240v 50hz. Whereas you guys are on 115v 60hz.
Could that be the difference?
Here our 110v equipment is classed as Industrial Grade.
Dumb question really but what voltage is used in AUZ Guys?
Grizzly

[gham]

I have had a similar fault wear the thermistor wiring in a copeland scroll had shorted to the windings. I meggered the windings to earth and checked there resistance which also appeared normal. I then left the thermistor circuit shorted out and fitted a thermal overload to the compressor contactor. the compressor is still running today and I carried out the repair 4 years ago

[dougie]

hi gham
im dougie i live in edinburgh scotland.
my father in law and part of my wifes family live there.
they are all kiwis. my wife was born there. we have been married for 17 years this year and have two boys.
we may be thinking of moveing over can you tell me what the job fronts like.
cheers dougie.