TM 10-4610-232-12
Table 4-2. Unit Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 9. Set multimeter to Ohms x 1 scale and check for continuity between all pairs of motor leads, T1 and T2,
T1 and T3, T2 and T3. Readings should be zero or near zero for each step.
Replace motor if reading is infinity (para. 4-79).
Step 10. Check motor cable for continuity on each lead and for shorts between phases and ground. Replace
the cable if open or shorted (para. 4-79).
2. Air compressor motor hums but won't turn (Reference Schematic Diagram FO-1, Sheet 5, schematic lines
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Check generator voltage on all three phases. It must be 435-445 VAC on each phase.
(a) Adjust to correct voltage.
(b) If voltage is not correct on all three phases, refer to generator troubleshooting.
Check for correct voltage by starting the raw water pump. Alternately, turn on both switches for the
distribution pump and note if it runs.
If the 3-phase motors listed do not operate, notify direct support maintenance.
Check continuity, point-to-point, from P20A to J67A, P20B to J67B, P20C to J67C, and P20H to
J67D (Reference Interconnection Diagram FO-2, Sheet 16). Check each lead for shorts between
phases and shorts to the ground wire. The reading should be infinity for each check.
(a) Replace any cable assembly that shows open during continuity checks (para. 4-27).
(b) Replace any cable or connector that shows a short between phases or a short to ground
(c) Repair any hose or damaged wires in the external junction box (para. 4-76).
(d) Replace any MOV's in the external junction box that show physical damage or are shorted to
ground from the power terminal (para. 4-76).
Tag and disconnect motor leads (T1, T2, T3). Set multimeter to Ohms x 1000 scale and connect test
leads between each motor lead and the motor frame. Readings should be infinity for each step.
Replace motor if the meter reading is zero (para. 4-79).
Set multimeter to Ohms x 1 scale and check for continuity between all pairs of motor leads, T1 and T2,
T1 and T3, T2 and T3. Readings should be zero or near zero for each step.
Replace motor if reading is infinity (para. 4-79).
Check motor cable for continuity on each lead and for shorts between phases and ground.
Replace the cable if open or shorted (para. 4-79).
3. Air compressor circuit breaker opens whenever air compressor is started, ROWPU shuts down when air com-
pressor is started (Reference Schematic Diagram FO-1, Sheet 5, schematic lines 518-521).
Check for short circuits.
(a) Shut down the ROWPU. Shutdown the generator. Refer to electrical schematic Appx. I-1
and interconnect diagram Appx. I-2.
(b) Refer to air compressor won’t start troubleshooting, (malfunction 1) steps 4 thru 10.
VAN LIGHTS .
Van lights do not work (Reference Schematic Diagram FO-1, Sheet 10, schematic lines 1026-1030).
Step 1. Remove connector P10 from top of control panel. Check across J10A and J106 (Reference intercon-
nection Diagram FO-2, Sheet 9) for 110-120 VAC. Push either van light switch while testing.
If voltage is not present, go to step 3.
Step 2. Check the light cables and light fixtures for shorts and for continuity.
Replace any cables or fixtures that show they have shorts or open circuits (para. 4-27).
Change 1
4-75
