It is the release curve of the circuit breaker, the action characteristic curve of the circuit breaker quick-break release.
The release curve is divided into A, B, C, D, K and other types, the meaning of each is as follows:
1, A curve The release current is (2~3) In .
2, B curve, the release current is (3~5)In.
3, C curve: the release current is (5~10)In, suitable for the protection of distribution lines and lighting lines with high turn-on current.
4, D curve: the release current is (10~20)In, suitable for the protection of equipment with high inrush current, such as transformer solenoid valve.
5, K curve: with 1.2 times the thermal release action current and 8 ~ 14 times the magnetic release action range, suitable for the protection of motor line equipment, has a high resistance to inrush current.
If it is a micro-break: B type is 3~5 times the rated current when off C type is 5~10 times the rated current when off D type is 10~14 times the rated current when off According to the characteristics of the circuit breaker off the inverse time limit (that is to say, the higher the overload current, the shorter the time of off), and off characteristic curve graph (mainly to see how long under how much current around the time of off).
Expanded Information
Miniature Circuit Breakers
Miniature Circuit Breakers are one of the most widely used terminal protection appliances in the building electrical terminal power distribution devices. Used for 125A below the single-phase, three-phase short circuit, overload, overvoltage protection, including single-pole 1P, two-pole 2P, three-pole 3P, four-pole 4P and so on four kinds.
Low-voltage circuit breakers are mainly used in the design of civil buildings for line overload, short circuit, overcurrent, loss of voltage, undervoltage, grounding, leakage, automatic switching of dual power supply and infrequent starting of motor protection, operation and other purposes, the following conditions should be considered:
1, circuit breaker rated voltage should not be less than the rated voltage of the line.
2. The rated current of the circuit breaker and the rated current of the overcurrent disconnector shall not be less than the calculated current of the line.
3. The rated short-circuit breaking capacity of the circuit breaker shall not be less than the maximum short-circuit current in the line.
4, selective distribution circuit breaker need to consider the short delay short circuit breaking capacity and delay protection level with.
5, circuit breaker undervoltage disconnectors rated voltage is equal to the rated voltage of the line.
Baidu Encyclopedia - Miniature Circuit Breaker
Baidu Encyclopedia - Release Curve