Main function: assembled with circuit breaker to achieve over-voltage protection Rated operating voltage Ue: AC 230V, 50Hz; Overvoltage action setting value Uo: 280 (1 ± 5%) V; Undervoltage action setting value (35%~70%) Ue; Rated insulation voltage Ui: 500V; Tripping characteristics: The trip unit is combined with the NXB-63 series circuit breaker. When the applied voltage is as low as 70% Ue or rises to the overvoltage setting value of 280 (1±5%), the trip unit should drive the open circuit. Action. When the applied voltage is lower than 35% of the rated working voltage of the trip unit or higher than 105% of the setting value of the overvoltage action, the trip unit should prevent the circuit breaker from closing when the power supply voltage is higher than 85% of the rated working voltage. And when it is lower than 95% of the overvoltage action setting value, the circuit breaker can be normally closed. The upper limit of the applied voltage should be less than 110% of the overvoltage setting. Mechanical durability: The mechanical durability of the trip unit is not less than 4000 operating cycles.