TM 55-1930-209-14&P-13
WARNING
Drive wheels must be lowered to prevent accidental movement of bridge crane while repairs are
being made. Failure to do this may cause serious bodily harm.
c.
Lower drive wheels by loosening ¾ inch x 10 NC HEX and ¾ inch x 10 NC tam nut. Loosen two nuts on
each until both drive wheels are 1/8 inch to ¼ inch from the I-beam.
d.
Close disconnect switch, open lockout limit switches ON, FORWARD, and REVERSE. Check voltage at
motor connection inputs across terminal pairs T1 and T2, T1 and T3, and T2 and T3 for 440 Vac (in both
FORWARD and REVERSE modes). If 440 Vac is not apparent across one or more terminal pairs in both
modes, go to step e. If voltage is 440 Vac across all terminal pairs in one mode but not in the other mode,
go to step e. If voltage is 440 Vac across all terminal pairs, in both modes, replace motor.
e.
Check fuses F1, F2, F3, F4, F5, F6, and F7 for blown condition. If all fuses are in proper working
condition, go to step f. If any fuse indicates blown condition, replace with properly rated fuse.
f.
Check voltage at inputs of disconnect switch, across terminal pairs C1 and C2, C1 and C3, and C2 and C3
for 440 Vac.
If voltage across all terminal pairs is 440 Vac, go to step g. If voltage across any
terminal pair is not 440 Vac, perform steps (1) and (2), following, as necessary.
(1) Check voltage at outputs of cable reel across terminal pairs B1 and B2, B1 and B3, B2 and B3 for
440 Vac. If voltage across any terminal pair is not 440 Vac, go to step (2). If voltage across any
terminal pair is 440 Vac, repair wire(s) from cable reel to disconnect switch.
(2) Check voltage at inputs of cable reel across points A1 and A2, A1 and A3, and A2 and A3 for 440
Vac. If voltage across any terminal pair is not 440 Vac, repair or replace wire(s) from junction box-
to-cable reel. If voltage across all terminal pairs is 440 Vac, replace cable reel contacts or cable reel
assembly.
g.
Close (ON) disconnect switch and check voltage at outputs of disconnect switch across terminal pairs D1
and D2, D1 and D3, and D2 and D3 for 440 vac. If voltage across all terminal pairs is 440 Vac, go to step
h. If voltage across any terminal pair is not 440 Vac, replace disconnect switch.
h.
Check voltage at inputs of contractor (CM) across terminal pairs F1 and F2, F1 and F3, and F2 and F3 for
440 Vac. If voltage across all terminal pairs is 440 Vac, go to step i. If voltage across any terminal pair is
not 440 Vac, repair or replace wire(s) from fuse(s) to contractor (CM).
i.
With bridge hand control ON button pushed, check voltage outputs of contractor (CM) across terminal pairs
G1 and G2, G1 and G3, and G2 and G3 for 440 Vac. If voltage across all terminal pairs is not 440 Vac,
perform steps (1) through (4), following, as necessary.
(1) Check voltage across points A and B of magnetic coil CM for 11 5 Vac. If voltage is not 11 5 Vac,
replace starter CM.
(2) Check voltage at primary side of transformer T1 across points H 1 and H4 for 440 Vac. If voltage is
440 Vac, go to step (3). If voltage is not 440 Vac, replace or repair wire(s) from fuse(s) to
transformer.
(3) Check voltage at secondary side of transformer T1 across points X1 and X2 for 11 5 Vac. If voltage
is 11 5 Vac, go to step (4). If voltage is not 115 Vac, replace transformer.
WARNING
Make sure bridge crane motor is electrically dead before making continuity checks. Red tag
disconnect switch with: “WARNING - DO NOT ACTIVATE.
REPAIRS BEING MADE.”
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