Capacitor - Sinclair AMC-15A Service Manual

4. Apply "live" test cord probes on red wire and common terminal of capacitor. Motor should run
at low speed.
5. Apply "live" test cord probes on each of the remaining wires from the speed switch or system
switch to test intermediate speeds.
11.4

Capacitor

A run capacitor is wired across the auxiliary and main winding of a single phase permanent split
capacitor motor such as the compressor and fan motor. A single capacitor can be used for each
motor or a dual rated capacitor can be used for both.
The capacitor's primary function is to reduce the line current while greatly improving the torque
characteristics of a motor. The capacitor also reduces the line current to the motor by improving
the power factor of the load. Run capacitor hook-up line side of the capacitor is marked with a red
dot and is wired to the line side of the circuit
11.4.1 Capacitor test
1. Remove capacitor from unit.
2. Check for visual damage such as bulges, cracks, or leaks.
3. For dual rated, apply an ohmmeter lead to common (C) terminal and the other probe to the
compressor (HERM) terminal. A satisfactory capacitor will cause a deflection on the pointer, and
then gradually move back to infinity.
4. Reverse the leads of the probe and momentarily touch the capacitor terminals. The deflection of
the pointer should be two times that of the first check if the capacitor is good.
5. Repeat steps 3 and 4 to check fan motor capacitor.
NOTE: A shorted capacitor will indicate a low resistance and the pointer will move to the "0" end
of the scale and remain there as long as the probes are connected.
An open capacitor will show no movement of the pointer when placed across the terminals of the
capacitor.
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Basic test procedure