Density switch:
The density switch is a device that measures the ambient temperature compensated gas pressure, inside the circuit breaker. Therefore, alarm signal and blocking function are activated only if the pressure drops due to leakage.
The density switch includes normally: a scale display, one contact indicating the alarm pressure and two contacts controlling the gas-supervision interlocking relays at the blocking level.
Anti-pumping relay:
Anti-Pumping Relay is an Auxillary Relay used in the Closing Circuit of the Circuit Breaker for Protection of the Closing Coil and preventing the Hunting Effect in the Circuit Breaker.
Coils (closing and tripping) used in Circuit Breakers are not designed for continuous supply, because they don’t need to.
Whereas for closing coil, after the breaker is closed (can be manual or automated) there is a possibility that the continuous supply can be applied (in manual operation).
Anti pumping Relay opens the closing circuit instantly (faster than Aux. contact) and thereby prevents the Closing Coil from Burning.
Gas supervision:
Fail-safe Normally a switch with contacts closing at low gas-pressure is used.
Trip At low SF6 Another option is trip at low SF6-pressure.
TCS – Trip Circuit Supervision:
TCS – Trip Circuit Supervision:
TCS – Trip Circuit Supervision is mainly used to check the connection between the protection trip relay (control room) and the operating mechanism and secondly the trip coil(s) inside the operating mechanism(s).
Phase Discrepancy:
Phase discrepancy is a device that could be used on single pole operated circuit breakers, that uses auxiliary contacts to indicate that all phases are in the same position.
When the poles are in different positions a time relay starts, and after a pre-set time, a trip order and alarm signal are normally initiated.
When the poles are in different positions a time relay starts, and after a pre-set time, a trip order and alarm signal are normally initiated.
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