r is an electrical product used for security, also called MCB. Circuit breakers can be used to distribute electric energy, start asynchronous motors infrequently, protect power lines and motors, and automatically cut off the circuit when the line is severely overloaded or short-circuited or under-voltage. Its function is equivalent to a combination of a fuse-type switch and an overheating and overheating relay. Moreover, there is generally no need to replace parts after breaking the fault current.
In low-voltage power distribution systems, are used to replace the fuses and blade switches that were commonly used in the past. The circuit breaker has an automatic tripping function and is equipped with degaussing and arc extinguishing devices. In many distribution boxes, low-voltage circuit breakers have replaced fuses because fuses are disposable. Once the fuse blows, it must be replaced, which increases maintenance costs. But circuit breaker protection is in the form of tripping. After the fault is eliminated, the normal power supply can be restored by simply closing it, which is much more convenient than blowing the fuse in terms of maintenance and recovery.
The working principle of the circuit breaker is to use the upward thermal expansion and bending of the bimetal to trigger the lever to trip the circuit breaker and achieve overload protection. There is a certain time difference in overload protection. When the line is short-circuited or severely overloaded, the current passes through the induction coil to generate a strong magnetic field, pushing the lever to trip quickly.
If the power supply cannot keep up with the undervoltage, the voltage will drop dramatically. According to the P=UI formula, the smaller U is, the larger I is, and the smaller U is, the larger I is. According to Joule's law, the more the current rises, the more heat is generated by the devices on the line, and the temperature of the Delixi device will become higher and higher, which can easily cause fires and other accidents. Therefore, it is necessary to set a critical voltage for the line. When the line voltage drops to this critical voltage, the line will be cut off by a protection device or a device with similar functions to ensure that the components on the entire circuit will not burn out. This is called undervoltage protection. In the circuit breaker, when the grid voltage drops to a certain specified value, the attraction force of the electromagnet of the voltage loss release becomes smaller, so the lever rotates and acts on the tripping mechanism to open the circuit breaker and protect the circuit.

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