MN undervoltage release
The MN release opens the circuit breaker when its supply voltage drops to a value below 35 % of its rated voltage Un.
Undervoltage tripping, combined with an emergency-off button, provides fail-safe tripping.
The MN release is continuously supplied, i.e. if supply is interrupted:
either voluntarily, by the emergency-off button,
or accidentally, through loss of power or faulty wiring,
the release provokes opening of the circuit breaker.