TM 55-1930-209-14&P-2
Figure 4-2. Cooling Pump Motor Controller Schematic
(2)
Depress STOP switch and check continuity of wires from TB1 to TB3. If check indicates a closed
circuit, go to step (3). If check indicates an open circuit, check continuity of wires from TB1 to D2
and TB3 and D1. If check indicates an open circuit, replace faulty wires. If check indicates a
closed circuit in all wires, replace faulty STOP switch.
(3)
Depress START switch and check continuity of wires from TB2 to TB3. If check indicates a
closed circuit, go to step (4). If check indicates an open circuit, check continuity of wires from
TB2 to E2 and TB3 to E1. If check indicates an open circuit, replace faulty wires. If check
indicates a closed circuit in all wires, replace faulty START switch.
(4)
Check continuity of wires from main contactor coil connection U1 to TB2, auxiliary contact of main
contactor connection V2 to TB3, overload contact connection W1 to transformer connection X2,
and overload contact connection W2 to main contactor coil connection U2. If check indicates an
open circuit, replace faulty wires. If check indicates a closed circuit in all wires, go to step h.
h.
If no fault was found in steps e thru g, replace main contactor.
4-16
