DZ47-63 circuit breaker rated voltage is greater than or equal to the rated voltage circuit breaker; undervoltage tripping device rated voltage is equal to rated voltage lines; shunt tripping device rated voltage is equal to the supply voltage circuit breaker rated current; DC circuit breaker shell grade is greater than or equal to the line calculation of load current; circuit breaker rated current is greater than or the line is equal to the calculated current; rated short-circuit breaking capacity is greater than or equal to the maximum short-circuit current in the line at the end of the line; single phase short circuit current is greater than or equal to 1.5 times the circuit breaker instantaneous (or short delay) for tripping current setting; type circuit breaker should meet the installation requirements and operation conditions, protection performance the.

Recommendations are as follows:

(1) the rated current of the breaker is determined by the calculated current of the line;

(2) short circuit setting current of circuit breaker shall avoid the normal working start current of the circuit.

(3) check the breaking capacity of low voltage circuit breaker according to the maximum short-circuit current of the line;

(4) according to the minimum short-circuit current of the circuit to verify the sensitivity of the circuit breaker operation, that is, the minimum short-circuit current of the circuit should be no less than 1.3 times of the short-circuit current of the breaker;

(5) according to the short-circuit impact current on the circuit (that is, short circuit, full current, maximum instantaneous value) to check the short-circuit short-circuit capacity of the breaker (maximum current expected peak), that is, the latter should be greater than the former.