Electrical Maintenance
65
Current Relay Check the voltage between T1 and T2 at terminal 1 of the
current relay and between T1 and T2A at terminal 3 of the
current relay. If there is voltage between T1 and T2, but not T1
and T2A, the control coil is open. / Replace the current relay.
Check the voltage on 7EB at terminal 2 of the current relay with
unit control voltage (12 to 14 volts dc) present at 7EA on
terminal 4 of the current relay and the current relay energized
(current in T2A above 30 amps). If there is no control voltage or
low control voltage on 7EB when the current relay is energized,
the current relay is defective. / Replace the current relay.
Motor Start Relay Check the voltage on 7EC at the motor start relay with unit
control voltage (12 to 14 volts dc) present on 7EA and 7EB at
the motor start relay. If there is no control voltage or low control
voltage on 7EC, the motor start relay is defective. / Replace the
motor start relay.
Motor Start Contactor Line voltage must be present between T1 and T3 and T1 and
T31 at the motor start contactor. If not, check T3 from the motor
contactor to the start contactor. / Repair T3 as necessary.
Check the voltage between T1 and T3C and T1 and T3D with
control voltage present on 7EC at the motor start contactor.
Line voltage should be present. If no voltage is present, the
control coil of the start contactor is defective. If low voltage is
present, the points are defective. / Repair or replace the
contactor or points as necessary.
Problem/Probable Cause Test/Solution
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