TM 5-4310-384-13
Table 3-3. Troubleshooting
Malfunction
Test or Inspection
Corrective Action
ELECTRICAL SYSTEM
1.
ELECTRIC MOTOR WON'T START.
Step 1.
Check to see that main power and ON/OFF switch is ON.
Turn power ON.
Step 2.
Press RESET button on motor starter box.
Reset button will start motor only if relay was tripped by momentary overload.
Step 3.
Check pressure switch connections for tightness.
Tighten connections as necessary.
Step 4.
Check if pressure switch contacts are open at pressures below 160 psi.
Replace switch if contacts do not close. Refer to paragraph 3-21.
Step 5.
Check motor starter connections for looseness.
Tighten connections as necessary. Refer to paragraph 3-19.
Step 6.
Check motor controls for faulty wiring.
Wire controls correctly. Refer to paragraph 3-19.
Step 7.
Check for bad motor control coil. Check for continuity between terminals V and W of the coil.
Replace coil. Refer to paragraph 3-19.
Step 8.
Check for bad motor control contactor. Check for continuity across each pair of terminals.
Replace contactor. Refer to paragraph 3-19.
Step 9.
Check for burned motor control contacts.
Replace contactor. Refer to paragraph 3-19.
2.
MOTOR HUMS BUT WON'T RUN.
Step 1.
Check for power using voltmeter.
If voltage is incorrect, provide correct voltage.
Step 2.
Check for open or short circuited motor windings. Refer to paragraph 3-33.
If windings are defective, notify Intermediate Direct Support.
3.
LOW AIR PRESSURE.
Step 1.
Check to see if compressor cuts out at pressure below 190 psi.
Adjust pressure switch. Refer to paragraph 3-21.
Step 2.
Check pressure setting in pressure gage on regulator/filter.
Adjust to proper setting. Refer to paragraph 3-44.
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