The structure of low voltage circuit breaker
Release time:
2020-12-07
You probably know what circuit breakers are used for. However, if you are familiar with the structure and working principle of low-voltage circuit breakers, as well as some selection principles when selecting circuit breakers, many people may not be clear. Therefore, familiar with the structure, working principle, electrical symbols and functions of low-voltage circuit breakers and selection principles. Mastering the application of low-voltage circuit breakers in modern electrical control is something that modern people can learn. After all, the birth of circuit breakers has solved the safety problem of electricity consumption in our daily life, and everyone can choose with confidence.
There is a low-voltage circuit breaker in the circuit breaker, and the low-voltage circuit breaker is often referred to as an automatic air switch. The existence of low-voltage circuit breakers is an indispensable main electrical switchgear in the low-voltage distribution network. It can not only make and break normal load current, motor working current and overload current, but also make and break short-circuit current. So where are low-voltage circuit breakers used? Low-voltage circuit breakers are mainly used in low-voltage distribution lines or switch cabinets, provided that low-voltage distribution lines that are operated infrequently are used, in which low-voltage circuit breakers act as a power switch. And protect the lines, electrical equipment and motors. When they have serious overcurrent, overload, short circuit, phase failure, leakage and other faults, they can automatically cut off the line and play a protective role, which is widely used.
The working principle of the low-voltage circuit breaker is that when the circuit is short-circuited or severely overloaded, the armature of the overcurrent release is pulled in to make the automatic release mechanism act; when the circuit is overloaded, the heat generated by the thermal element of the thermal release Increase, make the bimetallic sheet bend upwards, and push the automatic release mechanism to act; when the circuit loses pressure, the armature of the pressure loss release is released, and the automatic release mechanism also operates. The automatic release mechanism acts to disconnect the main contact and cut off the main circuit, which play the roles of short-circuit protection, overload protection and under-voltage protection respectively.
When selecting low-voltage circuit breakers, pay attention to the following items:
1) The rated voltage and current of the circuit breaker should be greater than or equal to the normal working voltage and load current of the circuit.
2) The setting current of the thermal release should be equal to the rated current of the controlled load.
3) The rated voltage of the undervoltage release should be equal to the rated voltage of the circuit.
4) The circuit breaker should be installed vertically on the distribution board, the power lead should be connected to the upper end, and the load lead should be connected to the lower end.
5) The instantaneous trip setting current of the electromagnetic release should be greater than the peak current of the load circuit during normal operation.
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