In modern society, no matter whether it is industrial, agricultural, transportation, national defense, culture and education, finance, commerce, tourism services and people's lives, it is inseparable from electricity. In the generation, transmission and use of electricity, power distribution is an extremely important link, and circuit breakers play an important role in this link. The circuit breaker can be used to distribute electrical energy, and its function is equivalent to a combination of a fuse switch and an overheat thermal relay. Many people don't know how to choose the circuit breaker. The following small series will take you to know how to choose the circuit breaker.
First, the selection method of the circuit breaker
1, according to the type of load: mainly divided into distribution system and motor protection.
2. According to the capacity of the load: choose the rated current of the circuit breaker to be greater than the load working current.
3. According to the short-circuit current selection: the rated breaking short-circuit breaking capacity of the circuit breaker is greater than the expected short-circuit current value of the line. The short-circuit breaking capacity of the circuit breaker determines the reliability of the circuit breaker, but in the case of ensuring the safety of the line, it is not necessary to blindly pursue high-breaking property to cause waste.
Second, the selection of circuit breakers
1. Different breaking ability
There are two important indicators for the breaking capacity of the circuit breaker: the rated short-circuit breaking capacity Ics (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) and the rated limit short-circuit breaking capacity Icu (according to regulations) The conditions specified in the experimental procedure include the breaking capacity of the circuit breaker to continue to carry its rated current capability). The difference between the two is that the rated limit short-circuit breaking capacity means that the circuit breaker can re-run and then break the short-circuit current once after breaking the three-phase short-circuit current at the outgoing end, as to whether it can be normally connected and disconnected in the future, and is not guaranteed. . However, the rated short-circuit breaking capacity of the rated operation can still be broken normally several times under the above conditions.
2, the use of circuit breakers
The choice of a single circuit breaker directly affects the choice of the overall accessory wiring and conductor cross section. The circuit breaker needs to be selected according to the overall composition of the system. In order to make a fault at any point on the line, the fault can be eliminated by the adjacent upper-level circuit breaker.
The above series is for everyone to choose the circuit breaker selection method and selection considerations. The main functions of the circuit breaker are: 1. Turning on and off the no-load and load current in the high-voltage circuit under normal conditions; 2. In the system When a fault occurs, it can cooperate with the protection device and the automatic device to quickly cut off the fault current and prevent the accident from expanding, thus ensuring the safe operation of the system. It can be seen that the circuit breaker is closely related to our daily life. It is necessary to correctly select and use the circuit breaker. I hope that when selecting the circuit breaker, we can select the appropriate product according to the actual situation.