comp efficiecy test

[jat2020]

working an a copeland compressor today and was doing an efficiecy test on the compressor with copeland calculator . had 15psi suction and 225 psi discharge and the calculator said i should be drawing 7.9 amps. well i checked the common wire and got 7.7amps o.k. but then i went to the run lead and was only getting 4.5 amps now what is going on shouldnt i get 7.7 amps on both if the compressor is good?

[return fan]

i know you have a Copeland, but with the literature that came with a bristol compressor i replaced some time ago it said to check the start winding current on start up, with a run cap only you should see 2-10 amps, with a run and start cap you should see 20 amps then 2-10 amps when the compressor is running, then with a start capacitor(induction run) you should see 20 then drops to zero when the potential relay drops out. so if your measuring 4 amps on the run winding, the other 2 or 3 amps may be going thru the start winding, if your using one of the first to methods to start the compressor, if its a potential relay that drops out the start winding all together, then i have no idea where the other 2 amps went

[return fan]

id start looking at that potential relay pretty hard ,if thats what you have

[jat2020]

this compressor had both a run and start cap and the com= 7.9 amps run=4.5 and start =4.5 i just found it weird that the com and run winding werent drawing the same amount of amps.

[return fan]

and it has a potential relay to kick out the start cap once its running?

[jat2020]

yup