The Characteristics Of The Circuit Breaker
The characteristics of the circuit breaker are: rated voltage Ue; rated current In; overload protection
(Ir / Irth) and short circuit protection (Im); rated short-circuit breaking current (industrial circuit breaker Icu; household circuit breaker Icn), and the like.
Rated operating voltage (Ue): This is the voltage at which the circuit breaker is operating in normal (uninterrupted) conditions.
Rated current (In): This is the maximum current value that can be infinitely received by the circuit breaker with a special overcurrent trip relay at the ambient temperature specified by the manufacturer and does not exceed the temperature limit specified by the current receiving part.
Short-circuit relay trip current setting (Im): Short-circuit trip relay (instantaneous or short delay) for high fault current value when the circuit breaker to quickly trip, the trip limit Im.
Rated short-circuit breaking capacity (Icu or Icn): The rated short-circuit breaking current of the circuit breaker is the highest (expected) current value that the circuit breaker can break without damage. The current value provided in the standard is the rms value of the AC component of the fault current. When calculating the standard value, the DC transient component (always occurring in the worst case short circuit) is assumed to be zero. Industrial circuit breaker ratings (Icu) and household circuit breaker ratings (Icn) are usually given in the form of kA rms values.
Short-circuit breaking capacity (Ics): rated breaking capacity of the circuit breaker is divided into rated short-circuit breaking capacity and rated running short-circuit breaking capacity of two.
GB "low-voltage switchgear and control equipment, low-voltage circuit breaker" (GB14048.2-94) on the circuit breaker rated short-circuit breaking capacity and rated operation of short-circuit breaking capacity made the following explanation:
1, the rated limit of the circuit breaker short circuit breaking capacity (Icn): according to the provisions of the provisions of the experimental procedures, does not include the circuit breaker to continue to carry its rated current capacity of the breaking capacity;
2, the rated operation of the circuit breaker short circuit breaking capacity (Icn): according to the provisions of the provisions of the experimental procedures, including the circuit breaker to continue to carry its rated current capacity of the breaking capacity;
3, the rated limit short-circuit breaking capacity (Icn) test procedures for the O-t-CO.