The rated breaking capacity of the circuit breaker is divided into two types: rated ultimate short-circuit breaking capacity and rated running short-circuit breaking capacity. The national standard "Low-voltage switchgear for low-voltage switchgear and control equipment" (GB14048.2-94) explains the rated ultimate short-circuit breaking capacity and rated short-circuit breaking capacity of the circuit breaker as follows:

(1) The rated ultimate short-circuit breaking capacity of the circuit breaker (Icn): according to the conditions specified in the specified experimental procedures, does not include the breaking capacity of the circuit breaker to continue to carry its rated current capability;

(2) rated operation short-circuit breaking capacity (Icn) of the circuit breaker: according to the conditions specified in the specified experimental procedures, including the breaking capacity of the circuit breaker to continue to carry its rated current capability;

(3) The test procedure for rated ultimate short-circuit breaking capacity (Icn) is O-t-CO.

The specific test is: adjust the current of the line to the expected short-circuit current value (for example, 380V, 50kA), and the test button is not closed, the circuit breaker under test is in the closing position, press the test button, the circuit breaker passes 50kA Short-circuit current, the breaker immediately breaks (open for short O), the circuit breaker should be intact, and can be closed again. t is the intermittent time, generally 3min. At this time, the line is still in the hot standby state, and the circuit breaker is once again turned on (closely referred to as C) and immediately after the opening (O). (The connection test is to check the circuit breaker at the peak. Electric and thermal stability at current). This program is CO. If the circuit breaker can be completely disconnected, its ultimate short-circuit breaking capacity is qualified.

(4) The test procedure for the rated short-circuit breaking capacity (Icn) of the circuit breaker is O-t-CO-t-CO. It has one more CO than the test procedure of Icn. After the test, the circuit breaker can completely break and extinguish the arc, and it is determined that its rated short-circuit breaking capacity is qualified. -Dongguan Xunwang Hardware Products Factory

Therefore, it can be seen that the rated limit short-circuit breaking capacity Icn refers to the low-voltage circuit breaker can still operate normally after breaking the maximum three-phase short-circuit current at the outlet end of the circuit breaker, and then break the short-circuit current once again. Whether the circuit can be normally connected and disconnected, the circuit breaker is not guaranteed; and the rated short-circuit breaking capacity Ics refers to the circuit breaker can be normally disconnected multiple times when the maximum three-phase short-circuit current occurs at the outlet end. -Dongguan Xunwang Hardware Products Factory

Dongguan Xunwang Hardware Products Factory specializes in: metal stamping parts, computer heat sink processing, circuit breaker special motor, molded case circuit breaker, circuit breaker energy storage motor, circuit breaker motor, is a professional Dongguan motor production factory. Tel: 0769-86958478 Mr. Wang. Welcome all merchants to call to discuss cooperation!