| |
Back
Table 7-5.—Troubleshooting chart for alternating-current controllers—Continued | Up
Construction Electrician Basic - Electricity handbook for electricians | Next
Appendix I Glossary |
Table 7-5.—Troubleshooting chart for alternating-current controllers—Continued
Trouble
Arcing at Contacts
Pitting or Corroding of
Contacts
Noisy Operation (Hum or
Chatter)
Vibration after Repairs
Probable cause
Arc not confined to proper path.
Inadequate spring pressure.
Slow in opening.
Faulty blowout coil or connection.
Excessive inductance in load circuit.
Too little surface contact.
Service too severe.
Corrosive atmosphere.
Continuous vibration when contacts are
closed.
Oxidation of contacts.
Poor fit at pole face.
Broken or defective shading coil.
Loose coil.
Worn parts.
Misalignment of parts.
Loose mounting.
Incorrect coil.
Too much play in moving parts.
Remedy
Adjust or renew arc chutes. If arcing
persists, replace with more suitable
controller.
Replace worn contacts. Adjust or replace
weak springs.
Remove excessive friction. Adjust spring
tension. Renew weak springs. See
SLUGGISH OPERATION.
Check and replace coil.
Tighten connection.
Adjust load or replace with more suitable
controller.
Clean contacts and adjust springs.
Check load conditions and replace with
more suitable controller.
Use airtight enclosure. In extreme cases,
use oil-immersed contacts.
Change or improve mounting of
controller.
Keep
clean,
reduce
excessive
temperature, or use oil-immersed
contacts.
Realign and adjust pole faces.
Replace coil.
Check coil. If correct size, shim coil until
tight.
Replace with new parts.
Realign parts and test for free movement
by hand.
Tighten mounting bolts.
Replace with proper coil.
Shim parts for proper tightness, and
clearance.
7-56
|
