Air switch, I think everyone has heard of it. Each of our families has a distribution box, and the switches in the distribution box are air switches, whether with or without leakage, they are air switches. So now a friend asks such a question: why is an air switch called an air switch? What does it have to do with air? To understand this problem, we need to understand the air switch classification and how it works.
Classification of Switches
1) Switches, including our common circuit breakers, disconnectors, fuses, etc. And what we call an air switch, it is a circuit breaker, a kind of circuit breaker.
2) The circuit breaker can be divided into high voltage circuit breaker and low voltage circuit breaker according to the range of its use, that is, the installation location. The air switch used in our home is one of the low voltage circuit breakers.
3) If we divide according to the arc extinguishing mode of the switch, then the circuit breaker can be divided into multi-oil circuit breaker, oil-less circuit breaker, sulfur hexafluoride circuit breaker, vacuum circuit breaker, compressed air circuit breaker, air circuit breaker, SF6 combination electric appliance.
4) Therefore, the air switch is divided according to the arc-extinguishing method of the circuit breaker, so as to obtain a name.
Air switch is used in our home, as long as the current in the circuit exceeds the rated current of the air switch, the air switch automatically disconnects and then cuts off the power supply. This can effectively prevent the circuit from burning out due to excessive current.
When the air switch automatically disconnects the switch, there will be an arc at this time, and the air switch uses air as the medium of arc extinguishing to automatically cut off the circuit. Therefore, air switches are mainly named according to their way of arc extinguishing, and the medium of air switch arc extinguishing is air.
Arc Extinguishing Principle of Air Switch
The above said that the air switch arc extinguishing medium is air, so how does it use air to extinguish the arc? The air switch arc extinguishing is a complicated process. below Jiangsu Starlight to give you a summary, so that we can understand clearly.
Air switch tripped for some reason, the action of the air switch action is also the moment of trip, the air switch contact will separate, and an arc will be generated between the separated contacts. At this time, the magnetic field produced by the arc current is opposite to the magnetic field induced by the arc chute of the air switch, can attract each other. As a result, the arc will be attracted to the arc gate, so that the arc will be elongated, until after entering the arc gate, it can be quickly cooled out, which is such a process, the arc produced will be extinguished.
Tripping Mode of Air Switch
There are three main modes of air switch is mainly three. The first is an electromagnetic trip. The second is a thermal trip. The third is a compound trip.
Short circuit protection corresponds to electromagnetic tripping. Electromagnetic trip refers to the air switch, when the coil through the load current, its electromagnet suction is relatively small. When passing through the short circuit current, the suction is relatively large, so that the armature action drives the trip, the trip carries on the power cut.
Overload protection corresponds to thermal trip. Thermal trip means that in the air switch, when the circuit is overloaded, the overload current can make the components in the switch produce a certain amount of heat, and the heat generated will lead to the deformation of the bimetallic strip, so that the trip device trip, and then the circuit can be disconnected.
Compound tripping, air switch in the internal compound tripping is generally used by metal sheet. When the circuit knows that the current reaches a certain load current, it will generate heat, and these heat will also deform the metal sheet, which can lead to degassing and tripping, so that the power supply is disconnected. At the same time, when the coil in the air switch flows through a large short-circuit current, the tripper also acts. Therefore, the compound tripping can not only play a short circuit protection, but also play an overload protection.
Some Other Knowledge of Air Switch
Air switch is a very common in our low voltage power grid, but also a very important electrical appliance. It combines control and multiple protections. In addition to switching on and off the circuit, it can also protect the circuit and electrical equipment from short circuit, overload and under-voltage. In addition, it can also be used to start the motor infrequently.
The common air switches in our family are ordinary air switches, so the internal trip curves of these air switches are basically determined when they leave the factory. Therefore, the arc extinguishing ability of these air switches is also determined. However, if a professional can fine-tune the internal spring of the air switch, it can increase the speed of arc extinguishing, but can not improve the ability to extinguish arc.
Starlight can provide multiple brands of diesel generator set air switch, including Schneider switch, SIEMENS switch and Delixi switch, ABB switch, etc. Customers can choose the right switch according to theirs needs.