Main function: assembled with circuit breaker to achieve undervoltage protection Rated operating voltage Ue: AC 230V, 50Hz; Rated insulation voltage Ui 500V; Undervoltage action setting: (35% ~ 70%) Ue; Operating characteristics: external voltage ≤ 35% Ue, the product should prevent the circuit breaker from closing; 35% Ue ≤ external voltage ≤ 70% Ue, The product moves and drives the circuit breaker to open; the applied voltage ≥85%Ue, the product should be able to close. The applied voltage value should not exceed 110% Ue. Mechanical durability: The mechanical durability of the trip unit is not less than 4000 operating cycles.