Undervoltage release the power supply voltage is equal to the rated working voltage release

The MCB has delayed or disconnected without delay a trip, when the supply voltage drops (or even slow down) to the rated working voltage of 70 to 35 percent range, under voltage release should operate under voltage release the power supply voltage is equal to release 35% of rated voltage when undervoltage release should be able to prevent the MCB is closed; supply voltage is equal to or greater than 85% undervoltage  lectri cenergy meter  working voltage, should guarantee MCB reliable closure. Therefore, when the power  mcb circuit breaker  by the protection circuit in a voltage drop occurs, automatically open the MCB cut off, so that the electrical load of the following MCB or electrical equipment from damage due to voltage.