LV Systems


A contactor is an electrically controlled switch used for switching an electrical power circuit, similar to a relay except with higher current ratings.

The maintenance of circuit breakers deserves special consideration because of their importance for routine switching and for protection of other equipment.Electric transmission system breakups and equip­ment destruction can occur if a circuit breaker fails to operate because of a lack of preventive maintenance.The need for maintenance of circuit breakers is often not obvious as circuit breakers may remain idle,

either open Breakers that remain idle for 6 months or more should be made to open and close several times in succession to verify proper operation and remove any accumulation of dust or foreign material on moving parts and contacts.

S.No Description
1 General Maintenance of Drive Mechanism.
2 Checking healthiness of Shunt/Under Voltage release if available.
3 Checking motorised operation if available.
4 Checking proper working conditions of operating handle for its position.
5 Checking Tightness of control wiring Terminals and bus conductors.
6 IR Values of Breaker. a. In ON Pos. R-E/Y-E/B-E/RY/YB/BR b. In OFF Pos. R-R/Y-Y/B-B.
7 General checking of MCCB for any abnormal condition.