TM 10-4610-232-34
Table 2-1. Direct Support Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
When checking continuity in the power circuits, it is important to watch the wire numbers
on each phase. Each wire is tagged identically on both ends, but in some instances, a #1
phase wire will enter the top of a starter or circuit breaker and come out the bottom of the
same device as #2 phase wire. This is done to change the rotation of a motor so that its
associated pump will turn in the correct direction. Any two wires may be interchanged to
accomplish this rotational change.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace circuit breaker CB3 (REF: Interconnection diagram FO-2, Sheet 10) if open on any phase
(para. 2-23).
(c) If MS1 (REF: Interconnection diagram FO-2, Sheet 10) shows open on any phase, replace/repair it
(para. 2-25).
(d) Replace/repair J19 if faulty (para. 2-21).
Step 13. Shut down ROWPU and generator. Disconnect the cable from the ROWPU to the generator at the generator
end. Check continuity, point-to-point, from the generator end of the cable to the power distribution block
(PDB) on each phase.
(a) Replace the main power cable if open on any phase (para. 2-18).
(b) Replace circuit breaker CB1 (REF: Interconnection diagram FO-2, Sheet 10) if open (para. 2-25).
(c) Repair any loose or damaged wire (para. 2-20).
(d) If the above checks have not revealed the problem, refer to generator troubleshooting.
2. Distribution pump motor hums but will not turn. (Ref. Schematic diagram FO-1, sheet 5, schematic lines 524-526).
Step 1. Check if other 3 phase motors operate.
If other motors do not operate, go to step 3.
Step 2. Shut down ROWPU and generator. Refer to electrical drawings in Appendix D. Check continuity, point-to-
point, from the power distribution block (PDB) (REF: Interconnection diagram FO-2, Sheet 10) to J19 (REF:
Interconnection diagram FO-2, Sheet 16) on the following lines: AL1 to J19A, AL2 to J19B, and AL3 to J19C.
Depress the operating plunger on MS2 (REF: Interconnection diagram FO-2, Sheet 10) when checking
across its contacts. Disconnect the J19 connector when testing.
NOTE
When checking continuity in the power circuits, it is important to watch the wire numbers
on each phase. Each wire is tagged identically on both ends, but in some instances, a #1
phase wire will enter the top of a starter or circuit breaker and come out the bottom of the
same device as #2 phase wire. This is done to change the rotation of a motor so that its
associated pump will turn in the correct direction. Any two wires may be interchanged to
accomplish this rotational change,
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace circuit breaker CB3 (REF: Interconnection diagram FO-2, Sheet 10) if open on any phase
(para. 2-25),
(c) If an MS2 overload is open, replace it and continue troubleshooting to find cause (para. 2-25).
(d) If MS2 shows open any phase, replace/repair it (para. 2-25).
(e) Replace/repair J19 if faulty (para. 2-21 ).
Step 3. Shutdown ROWPU and generator, Disconnect the cable from the ROWPU to the generator at the generator
end. Check continuity, point-to-point, from the generator end of the cable to the power distribution block
(PDB) on each phase,
(a) Replace the main power cable if open on any phase (para. 4-18).
(b) Replace circuit breaker CB1 (REF: Interconnection diagram FO-2, Sheet 10) if open (para. 2-25).
(c) Repair any loose or damaged wire (para. 2-20).
(d) If the above checks have not revealed the problem, refer to generator troubleshooting.
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