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. Air circuit breaker is used to distribute electric energy and protect the overload, undervoltage and short circuit of power line and power equipment.

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.

Working principle of air circuit breaker

The operation of DW45 circuit breaker 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.

Matters needing attention for closing of air circuit breaker

1) Before closing operation, check that the air circuit breaker is fully (from cold standby) into (in) the hot standby state. It includes: the disconnectors on both sides of the air circuit breaker are already in position after closing, the main and auxiliary protective relays of DW45 circuit breaker have been put into operation according to regulations, and the closing energy and operation control energy have been put into operation. The position signals are correct.

2) Operate the air circuit breaker to control the handle. The control handle is twisted to the closing position, and the instrument indication appears instantaneous impact (no change in short and empty lines). It can be returned after the red light is on. It can not be returned too fast, so that the air circuit breaker has no time to close.

3) After switching on and off, check the ammeter pointer return to zero in the switching circuit of DW45 circuit breaker, and check the measuring instrument, signal indication and mechanism position on the spot. For example, the ammeter, the power meter in the circuit with the load of the instructions, the switch-off position indicator, etc., so as to make a good judgment of the correct operation results.