MX Shunt Release MN Undervoltage Release For CNS CNT CNW

Remote tripping

This function opens the circuit breaker via an electrical order. It is made up of:

• a shunt release 2nd MX
• or an undervoltage release MN
• or a delayed undervoltage release MNR = MN + delay unit.

These releases (2nd MX or MN) cannot be operated by the communication bus.
The delay unit, installed outside the circuit breaker, may be disabled by an emergency OFF button to obtain instantaneous opening of the circuit breaker.

Voltage releases 2nd MX

When energised, the 2nd MX voltage release instantaneously opens the circuit breaker. A continuous supply of power to the 2nd MX locks the circuit breaker in the OFF position.

Instantaneous voltage releases MN

The MN release instantaneously opens the circuit breaker when its supply voltage drops to a value between 35 % and 70 % of its rated voltage. If there is no supply on the release, it is impossible to close the circuit breaker, either manually or electrically. Any attempt to close the circuit breaker has no effect on the main contacts. Circuit breaker closing is enabled again when the supply voltage of the release returns to 85 % of its rated value.