Troubleshooting
3A6393D
25
Air Compressor
Problem
Cause
Solution
Motor does not start
No power to the motor
Check the circuit breakers
Motor trips the circuit
breakers. Motor hums but
does not rotate.
The starting switch failed
1. Disconnect the air compressor from electrical power.
2. Open the motor electrical cover to access the
terminals.
3. Measure the resistance between terminal 4 and
terminal 5 while no power is applied to the motor.
4. If the resistance between terminal 4 and terminal 5 is
greater than 2 ohms, replace the motor.
The starting capacitor failed 1. Disconnect the air compressor from electrical power.
2. Open the motor electrical cover to access the
terminals.
3. Remove one wire from the capacitor to isolate the
capacitor from the other circuitry.
4. Measure the capacitance between the terminals on
each capacitor.
The smaller capacitor (AA, the starting capacitor)
should measure:
• 120 V model: 400–480
µ
F
• 230 V model: 124–149
µ
F
The larger capacitor (AB, the running capacitor)
should measure 37.6–42.4
µ
F.
If either capacitor is outside the capacitance range,
replace the faulty capacitor.
Motor runs for a short time
before turning off
The motor is overheating
Clean the air compressor motor and the intake air filter.
Poor motor performance
The compressor is worn
Replace the air compressor piston, seals, and sleeve.
Use the air compressor rebuild kit 287330 (120 V
systems) or 287331 (230 V systems).
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