Air circuit breaker is a kind of protective device suitable for distribution network with 50/60Hz AC, rated voltage 400V, rated working current up to 1000A and below. It is used to distribute electric energy and protect line and power equipment from overload, undervoltage, short circuit, single-phase grounding and other faults.

Air 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.

Use and maintenance of air circuit breaker
1. When the circuit breaker is used, the rust preventive oil on the pole of the magnet should be wiped off and kept clean.
2. Lubricating oil must be added regularly to the rotating shaft holes and friction parts.
3. The circuit breakers should be regularly checked during use to ensure safety and reliability in use.
(1) Clean the dust regularly to keep the insulation level of the circuit breaker.
(2) Check the contact system on schedule. (Note: the circuit breaker should be isolated when checking.)
a. Check the burning degree of arc contacts. If the small opening distance of the main contact is less than 2 mm when the dynamic and static arc contacts are just contacted, the arc contacts must be readjusted or replaced.
b. Check the electrical wear degree of the main contact. If small metal particles are found on the main contact, they should be removed and repaired in time. If the overrun of the main contact is less than 4 mm, it must be readjusted. If the silver alloy thickness on the main contact is less than 1 mm, the contact must be replaced.
c. Check the soft joint fracture and remove the broken layer. If the long-term use is soft, the fracture is serious (close to 1/2). It should be replaced in time.
4. When the circuit breaker breaks the short-circuit current, besides checking the contact system, it is necessary to clear the smoke marks on the two walls of the arc extinguishing cover and check the burning of the arc extinguishing grating. If it is serious, the arc extinguishing cover should be replaced.


Circuit breakers can be divided into fixed type and drawer type. If fixed type circuit breakers are loaded into special drawer holders, they will become drawer type circuit breakers. The circuit breaker body is composed of contact system, arc extinguishing system, operating mechanism, current transformer, intelligent controller and auxiliary switch, secondary plug-in, under-voltage, tap-off and other components.

Contact system of DW45 circuit breaker
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 multi-way parallel connection to reduce the electric repulsion force and improve the contact system. The electrical stability.

Arc extinguishing chamber of DW45 circuit breaker
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.

Operation mechanism of DW45 circuit breaker
The mechanism is located on the front side of the 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.