IDENTIFYING UNMARKED SINGLE-PHASE PSC AND CSR MOTOR TERMINALS MEASUREMENT PROCEDURE
|15. Turn power ) off. Use the capacitor discharge too! (Figure SP-8-6) to discharge|
run capacitors and any other capacitors in the unit. Locate the
cted to the compressor motor windings and start circuit. (Refer
|The wiring related to the compressor motor and its starting circuit is identified. All
high-voltage capacitors used in the equipment are discharged, including the run
and start capacitors.
|16. Isolate the compressor from the remainder of the circuit by disconnecting the|
compressor leads from all components, including the run and start capacitors
and start relay.
|Compressor leads disconnected from other unit wiring to measure compressor
motor resistance only.
|17. Set up the VOM/DMM to measure resistance on the R x 1 ohm scale. Make|
sure the meter is zeroed. Measure across the three motor leads to find the
two motor terminals that give the highest resistance reading as shown in
Figure SP-9-19, View A.
|The two wires that produce the highest reading are the run and start windings.
The VOM/DMM is reading the combined (series) resistance of the run and start
winding. The remaining wire is connected to the motor C (common) terminal.
Mark this wire as the C terminal. Proceed to step 18 to determine other terminals
through the process of elimination.
|18. Connect one lead of the VOM/DMM to the C terminal wire, identified in step|
17. Touch the other meter lead to each of the remaining two compressor
motor wires to find the highest resistance as shown in Figure SP-9-19,
|The highest resistance is the S (start) terminal of the compressor motor. The
remaining terminal is the R (run) terminal.
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