Basic parameters of a circuit breaker
(1) rated working voltage Ue
The rated operating voltage refers to the nominal voltage of a circuit breaker, which can run continuously under the prescribed normal use and performance conditions.
(2) the rated current In
Rated current is the current that can be passed for a long time when the ambient temperature is below 40 degrees C. For a circuit breaker with a adjustable tripping device, it is the maximum current that the tripper can pass for a long time. Long term work is allowed when the ambient temperature is over 40, but not higher than 60.
(3) the current setting value Ir of overload release
The current exceeds the current setting of the tripping device Ir, and the circuit breaker is delayed. It also represents the maximum current that the circuit breaker can bear when it does not jump. The value must be greater than the maximum load current Ib, but it is less than the maximum current allowed by the line Iz.
The thermal relay relay Ir can normally be adjusted in the range of 0.7 to 1.0In, but if the electronic equipment is used, the adjustment range will be larger, usually 0.4 to 1.0In. For a circuit breaker equipped with an non - adjustable overcurrent relay relay, Ir=In.
(4) the current setting value of the short circuit tripping device Im
Short circuit release relay (instantaneous or short delay) is used for high fault current value, which makes the circuit breaker fast tripping, and its trip threshold is Im.
(5) rated short time tolerance current Icw
The current value that is allowed to pass through the agreed time. The current value is passed through the conductor in the agreed time, and the conductor will not be damaged by overheating. (6) breaking ability
The breaking ability of the circuit breaker refers to the ability of the circuit breaker to cut off the fault current safely. It has no necessary contact with its rated current, and there are 36KA, 50KA and other specifications. It is generally divided into the limit short circuit breaking capacity Icu and the operation short circuit breaking capacity Ics.
We're Here to Help