Bulk Oil Circuit Breaker Maintenance
1. Check contact burning. If burning is very light, remove the burn beads and polish the surface. If burning is quite heavy, replace the tips and arcing ring by new set. You should loose and tight the tips few times before final tightening is done.
2. Check the extinguishing chamber. If the condition of any part indicates severe burning, we should dismantle the chamber and replace the damaged parts immediately.
3. Clean and lubricate CB mechanism. The rust on the mechanism and from metal mechanism box surface should be removed by non fluffy cotton cloths. The mechanism including gear wheel should be lubricated by high grade grease. But remember that the friction clutch must be lubricated. In case of minimum oil circuit breaker, insulator must be cleaned. The manual provided by manufacturer for greasing and lubricating should also be followed beside this general instruction.
4. The locking pins of tie rods should be checked half yearly .
5. All the foundation bolts electrical terminal connections at CB power circuit must be tighten properly after removing oxide coating if nay and it must be done half yearly.
6. The proper adjustment of auxiliary switch by ensuring correct NO and NC contacts at breaker OFF and ON condition must be checked half yearly. Additionally, the auxiliary switch’s contacts should be cleaned properly with help of hard brushes.
7. The spring charging motor and mechanism should also be cleaned and associated bearing should also be lubricated half yearly.