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TROUBLESHOOTING AND REPAIR |
INPUT CONTACTOR TEST (continued)
FIGURE F.13 – INPUT CONTACTOR
CR 1 Contactor
272
Coil Terminals
Apply External
120vac Here
271
W (L3) | T3 |
V (L2) | T2 |
U (L1) | T1 |
L3 | T3 |
L2 | T2 |
L1 | T1 |
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Cover Plate Screws
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PROCEDURE
VOLTAGE TEST
1.Disconnect the input power and remove the Input Access Panel from the rear of the machine
2.Connect an AC voltmeter to the two coil terminals of the Contactor See Figure F.13.
3.Apply the 3 phase power to the
CONTACT TEST
1.Disconnect the input power and remove leads 271 and 272 from the CR1 coil terminals. See Figure F.13.
2.Remove the contactor cover plate, blow out any dust or dirt with low pressure air.
3.Examine the contacts for signs of arcing, sticking or pitting. If any of these conditions exist, the Contactor should be replaced.
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WARNING
ELECTRIC SHOCK can kill.
•Do not touch electrically hot parts.
4.If the meter shows 120vac and the Contactor does not operate, it is defective.
5.If the 120VAC is not present at the coil:
•Check the Power Switch, Thermostats and asso- ciated wiring. See the Wiring Diagram.
•Also check the Control Board LEDs to be certain that the machine is not in a “shut down” condition. See the PC Board Troubleshooting Guide.
•Check the CR 2 relay for proper operation.
4.With the cover back in place, apply an external 120VAC supply to the coil terminals and make sure the Contactor activates and is not ‘noisy’. A noisy contactor should be cleaned or replaced.
NOTE: A noisy or shorted contactor can damage the Control Transformer.
5.With an ohmmeter, check across each set of con- tacts for continuity (0 ⏐ ’s). See Figure F.13.
L1 t0 T1
L2 to T2
L3 to T3
If there is any resistance, replace the contactor.
6.Remove the 120VAC supply and
