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From the function of many types of circuit breakers, they have short circuit protection, overload protection, isolation protection, whether in accordance with the normal connection, or reverse connection, almost all of their protection functions can be realized.
But no matter from the national standard or from the operation habit, the air switch is different, is not qualified electrician, is absolutely not allowed.
Air switch upside down connection is very dangerous, and should be strictly prohibited behavior, no matter whether the air switch has other accessories, air switch reverse connection is very dangerous country at present there is no circuit breaker can reverse connection provisions. However, there is no shortage of some unique people trying to act in reverse, and there is nothing wrong with it. This is a kind of disregard for safety. The inlet line and outlet end of any kind of protective switch of electrical equipment must be able to cut off the main contact power supply in the line.
Automatic air circuit breaker. It can open and shut off the working current under load condition. At the same time, it can also protect the circuit from short circuit, overload and undervoltage. Automatic switch is widely used in low voltage distribution line, also used to control the motor and other electrical equipment.
There are many types of automatic switch structure, currently the more common frame type and plastic shell type. The number of poles can be divided into single pole, double pole, triple pole and quadrupole. According to the way of closing operation is divided into direct manual operation, lever operation, electromagnet operation and motor operation and other forms. Generally, automatic switches operate at the speed of a few tenths of a second, while the DC fast automatic switches used in semiconductor rectifier devices operate at less than 3ms.
The working principle of the general automatic switch is that the main contact is the dynamic contact, which is used to put on and break off the main circuit (through the load current), the transmission rod is locked, and the breaking spring is stretched; The coil of the overcurrent trip is connected in series to the main circuit. When the current of the main circuit is normal, the armature is in the release position. When the current of the main circuit exceeds the specified value, the armature is drawn, the top bar opens the locking buckle, and the breaking spring breaks the main contact (also known as switching), and also breaks the auxiliary moving contact. When the voltage of the main circuit is normal, the armature of the devoltage trip device is drawn. When the voltage of the main circuit is lower than the specified value, the armature is released, and the top bar will also open the lock, so that the main contact is broken. The auxiliary contact is the dynamic contact, which is connected in series with the devoltage trip coil; When the automatic switch is opened, the contact is broken at the same time, so that the loss of pressure trip device power. In the process of automatic switch closing (closing), a certain mechanism can make the auxiliary contact close first (not shown in the figure), so that the voltage loss trip coil is connected first, and then the main contact can close. Therefore, the automatic switch can not be closed under the condition of loss of pressure.
Not according to the set of cards and arbitrary automatic circuit breaker in and out of line connection, in addition to safety risks, there is also a short circuit breaking ability to decline the problem; Because the main function of circuit breaker in the circuit is short circuit protection, and time off short circuit current, any kind of circuit breaker can be broken short circuit current value, marked on the circuit breaker unit is KA, if the inlet and outlet line is reversed, will let the circuit breaker this parameter decline, when the short circuit fault moment, short circuit current exceeds the circuit breaker can be broken current value, When the circuit breaker is broken, it can not effectively extinguish the arc, it will burn out the active contact or static contact of the circuit breaker, and it will burn the line seriously.
