Speaking of miniature circuit breakers, presumably most people are still very unfamiliar with it, but in fact, it is very common in our daily life, such as some commercial, industrial and residential places, but we lack attention to it. And understand. Miniature circuit breaker, usually we also call it "miniature circuit breaker", as the name implies, a converter suitable for small AC voltage.

The working principle of miniature circuit breaker

working principle:

1. Overload protection-the realization of the circuit breaker's overload protection function is to use the principle that the bimetal is oriented and bent regularly as the temperature rises. After the miniature circuit breaker is closed, it will be in normal working condition. The internal bimetal generates heat due to a certain current passing through it. The two pieces of metal have different coefficients of thermal expansion and cause bending. The bending angle of the normal current (1.13In) is not large, so the thrust is not enough to trip the trip mechanism. When the line is generally overloaded, when the overload current (1.45In) is reached, The large bending angle of the bimetal touches the lever in the tripping mechanism, and the thrust is sufficient to push the tripping mechanism, so that the miniature circuit breaker trips and plays a role of overload protection. The magnitude of the current flowing through the miniature circuit breaker is different, and the degree of bending of the bimetallic sheet is also different. When the circuit is generally overloaded, the tripping time of the circuit breaker is generally longer because the overload current is not too large. The current time-current characteristics of the current GB10963.1-2005 standard stipulates that the overcurrent trip current is 1.45 times the rated current. The trip time should be within 1 hour.

2. Short-circuit protection-The short-circuit protection function of the circuit breaker is realized by the instantaneous release. According to the analysis of F=IN (the suction force is proportional to the product of the current and the number of turns), because the instantaneous release coil has a small number of turns (generally only less than 10 turns), although the instantaneous release is connected in series in the circuit, when the circuit is working normally , Due to the small number of turns, the suction force generated by the normal working current is not enough to overcome the reaction force of the spring, so the circuit can work normally. When the line is short-circuited or severely overloaded, a high current flows through the induction coil to generate a strong magnetic field. Since the current generated is different from the normal working current by several times or even tens of times or more, the number of coil turns has not changed. , But the current increases several times or even dozens of times, so the suction force has also increased several times or even dozens of times. Pushing the lever makes the circuit breaker trip quickly. Due to the large current, the tripping time of the circuit breaker is generally within 0.1s. Moreover, as long as the reaction spring is selected reasonably, it can meet the setting requirements of B, C, and D instantaneous releases.

Another important component is the arc extinguishing grid. At the moment the circuit breaker is closed, a large arc will be generated between the two contacts. The function of the arc extinguishing grid is to quickly disappear and reduce the arc by increasing the heat dissipation area and arc release space. The adverse effects produced.

Company Profile

Zhejiang ETEK Electrical Technology Co.,Ltd.was founded on January of 2011, which has more than 200 employees now. It is a professional manufacturing company engaged in R & D, production and sale of high and low voltage electrical products, such as terminal distribution electrical appliances, industrial distribution electrical appliances, industrial control electrical appliances, DC systems distribution appliances, etc. it possesses 3 major manufacturing departments and 1 import & export trading company. The three manufacturing departments are terminal distribution electrical appliances manufacturing department, industrial distribution electrical appliances manufacturing department and industrial control electrical appliances manufacturing department.

E-mail:sales@etek-china.com 

Tel: 86-577-62780116/62718777

Fax: 0086-577-62774090