Type C micro-break is used for general circuits, such as lighting circuits; D-type circuit breakers are used in power circuits such as electric motors, so can C-type micro-breakers be used in motor circuits?
Differences between C-type and D-type discontinuity:
Type C micro-break: including overload maintenance and short-circuit maintenance, the short-circuit maintenance tripping value is 5-10 times of the rated current; D-type micro-break: including overload maintenance and short-circuit maintenance, the short-circuit maintenance trip value is 10-20 times of the rated current; The overload maintenance is the same for both of them, and the difference is only in the short-circuit maintenance trip range.
Generally, there is no starting current for general loads, that is, the starting current is the rated current; The starting current of the motor is about 7-10 times of the rated current.
Generally, D-type 16A micro-break is selected as a maintenance electrical appliance, which is calculated according to 10 times the action current, and the short-circuit maintenance action current is 160A, which can avoid the motor starting current;
If you choose C-type 16A micro-break as the maintenance appliance, calculate according to 5 times the action current, the short-circuit maintenance action current is 80A, and you can't avoid the motor starting current; If the C-type 25A micro-break is selected as the maintenance appliance, it is calculated according to 5 times the action current, and the short-circuit maintenance action current is 125A, which can avoid the motor starting current; There are no technical problems.
Generally, the principle of selecting a circuit breaker is that the rated current of the circuit breaker is greater than the load current, and then select type C or type D according to the nature of the load. Type D is specially designed by the manufacturer for motor type loads, but it does not mean that the type C circuit breaker cannot be used, but the accounting method is adjusted under demand.
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