Post by coldspaces on Feb 14, 2014 4:47:34 GMT
I covered this some in my thread about the N & R relay modernization I did. My 52 International Harvester chest freezer came to me with a bad solid state start relay on it. I have no were to look up what I need by the model # of the box or compressor. If I had the part # off of the original relay that is long gone I might have found it in the Marrs cross reference. I don't even know for sure what the horse power rating of the compressor is.
This is how I will determine what to use. First I hooked a test cord to common and run connections on the compressor. Nothing is hooked to the start winding. I then plugged it in long enough to see what the locked rotor amps are of only the run winding.
In this case the run winging LRA is 13 amps.
Next I hooked up the start winding and started the compressor to check the normal running amps.
Right after start up it was drawing 3 amps
This tells me that my relay must close the contacts (pick up) at less that 13 amps. It then must open the contacts (drop out) higher than 3 amps.
The closest Marrs relays are the 27003 Pick up 6.8 amp drop out 5.8 amp or the 27004 pick up 8.3 amp drop out 7.1 amp.
Since I have an NOS Kilxon relay equivalent to the 27004 that will bolt on same as the original that is what I am planning to try.
I will let you know how it works.
This is how I will determine what to use. First I hooked a test cord to common and run connections on the compressor. Nothing is hooked to the start winding. I then plugged it in long enough to see what the locked rotor amps are of only the run winding.
In this case the run winging LRA is 13 amps.
Next I hooked up the start winding and started the compressor to check the normal running amps.
Right after start up it was drawing 3 amps
This tells me that my relay must close the contacts (pick up) at less that 13 amps. It then must open the contacts (drop out) higher than 3 amps.
The closest Marrs relays are the 27003 Pick up 6.8 amp drop out 5.8 amp or the 27004 pick up 8.3 amp drop out 7.1 amp.
Since I have an NOS Kilxon relay equivalent to the 27004 that will bolt on same as the original that is what I am planning to try.
I will let you know how it works.
