How does the air circuit breaker work?

Promulgator : TAIXIDate : 2018-10-13Views : 1808

Introduction of air circuit breaker
Air circuit breaker, also known as frame circuit breaker, is a kind of mechanical switching apparatus which can turn on, load and break the current under the condition of normal circuit, and can also turn on, load and break the current under the condition of specified abnormal circuit. ACB circuit breaker is used to distribute electric energy and protect the line from overload, undervoltage, short circuit, single-phase grounding and other faults; the circuit breaker has intelligent protection function, selective protection accuracy, can improve the reliability of power supply, avoid unnecessary blackouts.
The circuit breaker can be widely used in power plants, factories, mines and modern high-rise buildings, especially in the distribution system of intelligent buildings.

Features of air circuit breaker
Intelligent air circuit breaker is suitable for distribution network with AC 50Hz, rated voltage 380V, 660V and rated current 200A-6300A. It is mainly used to distribute electric energy and protect lines and power equipment from overload, undervoltage, short circuit, single-phase grounding and other faults. The circuit breaker has a variety of intelligent protection functions and can be selected. Selective protection, with precise action, avoids unnecessary power failure and improves power supply reliability. Under normal conditions, it can be used as an infrequent conversion of lines. Circuit breakers below 1250A can be used to protect motors from overload and short-circuit in networks with alternating current 50Hz voltage 380V. Under normal conditions, it can also serve as an infrequent starting motor.

The working principle of air circuit breaker
The operation of air circuit breakers depends on manual operation or electric closing. After the main contact is closed, the free tripping mechanism locks the main contact on the closing position. The coil of overcurrent tripper and the thermal element of thermal tripper are connected in series with the main circuit. Aluminum veneer is a new curtain wall material which uses high-quality aluminum alloy sheet as the base material and then is formed by numerical control bending technology and sprays decorative coating on the surface.
The coil of the undervoltage release is parallel to the power supply. When the circuit is short-circuited or seriously overloaded, the armature of the over-current release closes and the free release mechanism acts, and the main contact disconnects the main circuit. When the circuit is overloaded, the heat element of the thermal release causes the bimetal sheet to bend and pushes the free release mechanism to move. Distribution tripper is used as remote control. Practice has proved that TRIZ theory can greatly accelerate the process of invention and get high quality innovative products. In normal operation, the coil is power-off, in need of distance control, press the start button to make the coil energized, the armature drives the free release mechanism action, so that the main contact is disconnected.

Structure of ACB circuit breaker

1. Contact system
The contact unit has the function of both the main contact and the arc contact by adopting a one-stop contact system and different parts of the same contact; the new type of arc-proof contact can not cause excessive heating after breaking short-circuit current, and the temperature rise is too high; The contact system adopts multiple parallel connection to reduce the electric repulsion force and improve the electrical stability.

2. Arc extinguishing chamber
Each electrode is equipped with an arc extinguishing chamber. Its function is to separate the electrodes and insulate them from each other so as to isolate the other parts of the circuit breaker and the operators. The arc extinguishing chamber is all placed in the insulated base of the circuit breaker, which increases the mechanical strength of the arc extinguishing chamber wall and prevents the arc extinguishing chamber from bursting when the large short circuit current is interrupted.

3. Operating mechanism
The mechanism is located on the front side of the ACB circuit breaker. The mechanism uses the five link free release mechanism and is designed to store energy. In the process of operation, the mechanism is always in the pre-stored position, so long as the circuit breaker receives the closing order, the circuit breaker can be instantaneously closed. Pre release energy release button or closing electromagnet. The electric drive mechanism is self-contained, and the energy storage shaft and the main shaft are movably connected through a concave-convex wedge, so it is convenient to assemble and disassemble.