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Table 7-5.—Troubleshooting chart for alternating-current controllers—Continued | Up
Construction Electrician Basic - Electricity handbook for electricians | Next
Table 7-5.—Troubleshooting chart for alternating-current controllers—Continued |
Table 7-5.—Troubleshooting chart for alternating-current controllers—Continued
Trouble
Overheating of Coils
Continued)
Probable cause
D-c instead of a-c coil.
Too frequent operation.
Open armature gap.
Remedy
Replace with a-c coil.
Adjust to apply larger control.
Adjust spring tension. Eliminate
excessive friction or remove any
blocking in gap.
Contacts Welded Together
Improper application.
Check load conditions and replace with a
more suitable type controller.
Excessive temperature.
Smooth off contact surface to remove
concentrated hot spots.
Excessive binding of contact tip upon
Adjust spring pressure.
closing.
Contacts close without enough spring
Replace worn contacts. Adjust or replace
pressure.
weak springs.
Check armature
overtravel.
Sluggish operation.
See SLUGGISH OPERATION.
Rapid, momentary, touching of contacts Smooth contacts. Adjust weak springs.
without enough pressure.
Where controller has JOG or INCH
control button, operate this less
rapidly.
Overheating of Contacts
Inadequate spring pressure.
Replace worn contacts. Adjust or replace
weak springs.
Contacts overloaded
Check load data with controller rating.
Replace with correct size contactor.
Dirty Contacts.
Clean and smooth contacts.
High humidity, extremely dirty
See OVERHEATING OF COILS.
atmosphere, excessive condensation,
and rapid temperature changes.
High ambient temperature or poor
See OVERHEATING OF COILS.
ventilation.
Chronic arcing.
Adjust or replace arc chutes. If arcing
persists, replace with a more suitable
controller.
Rough contact surfaces.
Clean and smooth contacts.
Check alignment.
Continuous vibration when contacts are Change or improve mounting of
closed.
controller.
Oxidation of contacts.
Keep clean,
reduce excessive
temperature, or use oil-immersed
contacts.
7-55
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