Thermo King KD-II SR, Manual

Page: 74 / 182

Electrical Maintenance (Rev. 04/03)
60
Start Capacitors Voltage Test
With line voltage present between T1 and T3C and T1 and T3D
at the start capacitors, check the voltage between T1 and T3
and T1 and T3F. Both voltages should be within 10% of line
voltage. If one of the voltages is low, the start capacitor in that
circuit is defective. / Replace as necessary.
Current Test (NOTE: Only one of the two T3E and one of the
two T3F wires connected to the motor will carry a current
while starting.) Check the current through T3E and T3F at the
motor with an inductive ammeter during a start attempt. The
current in each wire should be 30 to 45 amps. If one of the
currents is low, the start capacitor in that circuit is faulty. If both
the currents are low, the motor start contactor did not close. /
Replace as necessary.
Motor Starts But Runs Poorly Or Slows
Down and Restarts
Run Transformer With line voltage present between L1A and L2A at the primary
winding of the run transformer, check the voltage between T3
and T3A and between T3 and T3B at the secondary windings of
the run transformer. The voltages should be 122 (+ 13/-8) volts.
If either voltage is less than 110 volts, the line voltage is low or
the run transformer is defective. / Replace as necessary.
NOTE: The transformer has a 208 volt tap and a 230 volt
tap. These taps are accessible on the test strip as L1B (208
volts) and L1C (230 volts). Wire L1A should be connected
to the tap that matches the line voltage of the power
source.
PROBLEM/PROBABLE CAUSE TEST/SOLUTION