TM 10-4610-232-34
Table 2-1. Direct Support Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
(c)
Replace any overloads on MS8-1M that show open (para. 2-25).
(d)
Replace the contacts on MS8-1M or MS8-2M that show open when the contactor is manually engaged
(para. 2-25).
(e) If the MOV’s (REF: Interconnection diagram FO-2, Sheet 16) in the high pressure pump assembly
junction box are damaged or grounded from the power terminal, replace them (para. 268).
Step 2. Check each resistor for damage and resistance.
Replace any resistor that is damaged or open (para. 2-25).
Step 3. Check for continuity across the MS8-2S and MS8-18 (REF: Interconnection diagram FO-2, Sheet 10)
contactors when they are manually engaged.
(a)
Replace the contacts on MS8-2S and MS8-1S contactors when they are manually engaged.
(b)
Replace the contacts on MS8-2S or MS8-1S that show open when the contactor is manually engaged
(para. 2-25).
Step 4.
Tag and disconnect motor leads T1, T2, T3, T4, T5 and T6. 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 the motor if any reading is zero (para. 2-71).
Step 5.
Set the multimeter to Ohms x 1 scale and check for continuity between all pairs of motor leads: T1 and T4, T2
and T5, T3 and T6. Readings should be zero or near zero.
Replace the motor if any reading is infinity (para. 2-71).
Step 6.
Check each motor cable for continuity on each wire and for shorts between wires in each cable.
Replace/repair the cables if open or shorted (para. 2-71).
4.
High pressure pump motor hums but will not turn (Ref. Schematic diagram FO-1, sheet 5, schematic lines 502-510).
Step 1.
Tag and disconnect motor leads T1, T2, T3, T4, T5 and T6. 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 the motor if any reading is zero (para. 2-71).
Step 2.
Set the multimeter to Ohms x 1 scale and check for continuity between all pairs of motor leads: T1 and T4, T2
and T5, T3 and T6. Readings should be zero or near zero.
Replace the motor if any reading is infinity (para. 2-71).
Step 3. Refer to control circuits okay but pump will not run for further checks (malfunction 3).
5.
High pressure pump circuit breaker trips when the pump is started. ROWPU shuts down when the high pressure pump
Is started. (Ref. Schematic diagram FO-1, sheet 5, schematic lines 502-510).
Check for a short circuit.
Refer to controls okay but pump will not turn troubleshooting (malfunction 3).
Refer to pump will not start troubleshooting. The motor is not switching from wye to delta circuits (malfunction 1).
6.
High pressure pump starts but does not come up to full speed.
Refer to pump will not start troubleshooting. The motor is not switching from wye to delta circuits (malfunction 1).
7.
High pressure pump is started but generator bogs down. (Also, see mechanical troubleshooting for same problem.)
Adjust wye to delta timing.
Adjust the timer on MS8-1M (REF: Interconnection diagram FO-2, Sheet 10) ¼ one second from its
present time to match up better with the generator horsepower/torque curves (para. 2-25).
8.
High pressure pump runs but the hourmeter does not operate. (Ref. Schematic diagram FO-1, sheet 6, schemaic line
636).
Shut down ROWPU and generator. Refer to electrical drawings in Appendix D and remove wire #2B from the high
pressure pump hourmeter. Check continuity, point-to-point, from MS8-1M (REF: Interconnection diagram FO-2,
Sheet 10) (wire #258) to ETM2 (REF: Interconnection diagram FO-2, Sheet 13) (wire #258). Check continuity,
point-to-point, from transformer T1(X2) (REF: Interconnection diagram FO-2, Sheet 10) to wire #2B on ETM2.
(a)
Repair any loose or damaged wire (para. 2-20).
(b) Replace hourmeter, ETM2, if the above checks are okay (para. 2-24).
2-72
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