Main characteristics of circuit breaker

(1) Rated operating voltage (Ue): This is the voltage at which the circuit breaker operates under normal (uninterrupted) conditions.

(2) Rated current (In): This is the maximum current value that a circuit breaker equipped with a specialized overcurrent trip relay can withstand infinitely at the ambient temperature specified by the manufacturer, without exceeding the temperature limit specified by the current bearing component.

(3) Short circuitrelayTrip current setting value (Im): Short circuit trip relay (instantaneous or short delay) is used to quickly trip the circuit breaker when high fault current values occur, with a trip limit Im.

(4) Rated short-circuit breaking capacity (Icu or Icn): The rated short-circuit breaking current of the circuit breaker isCircuit breakerThe highest expected current value that can be disconnected without damage. The current value provided in the standard is the root mean square value of the AC component of the fault current. When calculating the standard value, the DC transient component (which always occurs in the worst-case scenario of a short circuit) is assumed to be zero. The rated values of industrial circuit breakers (| cu) and household circuit breakers (Icn) are usually given in the form of the root mean square value of kA.

(5) Short circuit breaking capacity (Ics): The rated breaking capacity of a circuit breaker is divided into two types: rated ultimate short-circuit breaking capacity and rated operating short-circuit breaking capacity.

(6)Circuit breakerFree tripping: At any time during the closing process of a circuit breaker, if the protective action connects the tripping circuit, the circuit breaker can be reliably disconnected, which is called free tripping. A circuit breaker with free tripping can ensure that it can be quickly disconnected in the event of a short circuit fault when the circuit breaker is closed, which can avoid expanding the scope of the accident.