How to choose a miniature circuit breaker

Publish Time:2019-06-18 Author:admin Views:0

In the civil building design, the low-voltage circuit breaker is mainly used for line overload, short circuit, over current, voltage loss, under voltage, grounding, leakage, automatic switching of dual power supply and protection and operation of the motor during infrequent starting. Principles In addition to the basic principles of observing the environmental characteristics of low-voltage electrical equipment, the following conditions should be considered:

1) The rated voltage of the circuit breaker should not be less than the rated voltage of the line;

2) The rated current of the circuit breaker and the rated current of the overcurrent release are not less than the calculated current of the line;

3) The rated short-circuit breaking capacity of the circuit breaker is not less than the maximum short-circuit current in the line;

4) Selective power distribution circuit breakers should consider the short-delay short-circuit switching capability and the delay protection level coordination;

5) The rated voltage of the undervoltage release of the circuit breaker is equal to the rated voltage of the line;

6) When used for motor protection, select the circuit breaker to consider the starting current of the motor and make it not operate during the starting time; for design calculation, see “Industrial and Civil Power Distribution Design Manual”;

7) Circuit breaker selection should also consider the selective coordination of circuit breakers and circuit breakers, circuit breakers and fuses.