1. The action of the air circuit breaker is an important low voltage electrical protection. It can short-circuit, overload and more undervoltage protection, can also be used to start the motor and control circuitry and other off frequently. It is characterized by the need to replace the action elements, reliable, safe to use, easy to operate, big, breaking capacity (up to several thousand amperes or over).

2. The three main contact structure and working principle of the automatic air switch connected to the three-phase main circuit. Under normal circumstances, the tripping mechanism 2 by the lock key, and 3 consisting of the hook lock, the main contact 1 held in the on state. When the circuit is short-circuited, overload or under-voltage is not normal, the trip will trip and cut off the circuit automatically, in order to achieve the protective effect. , Once a short-circuit accident, in series with the main circuit overcurrent release coil 7 (only draw one phase) is generated as shown in FIG great electromagnetic suction, to pull the armature 9, pushing the lever 5 so that the top opening trip mechanism, the main breaking contact. When the grid voltage is decreased or disappeared severe undervoltage release coil 8 is energized, the armature 10 is released, and the tripping mechanism to open the top of the main breaking contact. When overloaded, since the heat release bimetal is bent, the same will trip open the top, breaking the main contacts.

3. Classification structure of many air circuit breaker, and two forms of conventional universal type (frame type) apparatus formula (Formula plastic housing). Universal switch can be realized in a variety of air flow protection, undervoltage, etc., widely used in industrial enterprises, like power plants and substations. Air switch apparatus compact structure, small volume, all of which is enclosed in the insulating conductive portions of the housing, it is very safe operation and use, it is widely used in electrical equipment general overcurrent protection.