NEWS & KNOWLEDGE

Low-voltage electrical appliances choose different types of short-circuit breaking capacity Circuit Breakers to meet the needs of different line expected short-circuit currents (when I is in the same situation). The selection principle of the circuit breaker is: the short-circuit breaking capacity of the circuit breaker ≥ the expected short-circuit current of the line. Different loads of low-voltage electrical appliances should choose different types of circuit breakers. The most common loads of low-voltage electrical appliances are distribution lines, motors and household and similar households (lighting, household appliances, etc.). Corresponding to this, there are distribution protection type, motor protection type and household and similar household protection type circuit breakers.

The protection properties and protection characteristics of these three types of circuit breakers are different. As far as distribution type circuit breakers are concerned, it is divided into Class A and Class B: Class A is a non-selective type, and Class B is a selective type. The so-called selective type means that the circuit breaker has three-stage protection characteristics of overload long delay, short circuit short delay and short circuit instantaneous. Most of the DW15 series, DW17 (ME) series, AH series and DW40, DW45 series in the universal (also known as frame type) circuit breaker are B type, while DZ5, DZ15, DZ20, TO, TG, CM1, TM30 and Some specifications of HSM1 series and universal DW15 and DW17 only have two-stage protection of overload long delay and short circuit instantaneous, they are non-selected type A circuit breakers. Selective protection.

- May 22, 2020-