The difference between air circuit breaker and vacuum circuit breaker

June 16,2022

china smart circuit breaker,High Quality circuit breakers,smart control circuit breaker

Smart control circuit breaker is a switching device that can close, carry and break current under normal circuit conditions, and can close, carry and break current under abnormal circuit conditions (including short-circuit conditions) within a specified time. High Quality circuit breakers can be used to distribute electric energy, start asynchronous motors infrequently, protect power supply lines and motors, etc.

When they have serious overload or short circuit and undervoltage faults, they can automatically cut High Quality circuit breakers, their functions are equivalent It can be used in combination of fuse switch and overheating relay. Moreover, it is generally not necessary to change the components after breaking the fault current.

China smart circuit breaker is generally composed of contact system, arc extinguishing system, operating mechanism, trip unit, housing, etc. Circuit breakers are classified into miniature circuit breakers, molded case circuit breakers and frame circuit breakers according to their structure.

The air smart control circuit breaker is what we use the most every day, especially for novice electricians, who do not have much contact with vacuum circuit breakers, and have never even heard of them. But we take it literally, there is an air circuit breaker, and naturally there is a vacuum circuit breaker opposite to it. What is the difference between this vacuum circuit breaker and an air circuit breaker?

[Air switch] is a switch that will trip as long as there is a short circuit. When the line is short-circuited or severely overloaded, the short-circuit current exceeds the instantaneous trip setting current value, and the electromagnetic release generates enough suction to attract the armature and hit the lever, so that the hook rotates up around the shaft seat and releases the lock. , the lock will disconnect the three main contacts under the action of the reaction spring to cut off the power supply.

When the line is generally overloaded, although the overload current cannot make the electromagnetic release operate, it can make the heating element generate a certain amount of heat, which will make the bimetallic sheet bend upward when heated, push the lever to disengage the hook and the lock, and release the main contact The head is disconnected and the power is cut off. Because there are many ways of insulation, there are oil switches, vacuum switches and other inert gas (sulfur hexafluoride gas) switches. The air switch is a switch that uses air to extinguish the arc, so it is called an air switch. Air is used to extinguish the arc generated during switching. That's why it's called an air switch.

The so-called "air" and "vacuum" originally referred to their different arc extinguishing devices. The air circuit breaker relies on the arc extinguishing device, which elongates the arc, and then relies on air to cool the arc (what is an arc? Well, it is arc or spark). The vacuum circuit breaker relies on vacuum to extinguish the arc, and there is a vacuum bubble inside.

This leads to the second difference. The air circuit breaker relies on compressed air to perform the opening or closing action, and the vacuum circuit breaker cannot use the air storage chamber due to its high vacuum characteristics. Therefore, the vacuum circuit breaker relies on the electric valve and the electromagnet to control the circuit. opening and closing.

The detailed action process of the air circuit breaker is as follows:

Before the action of the air circuit breaker, the air storage cylinder should be filled with enough compressed air; the D cavity of the starting valve should be filled with compressed air; and a small amount of compressed air will enter the arc extinguishing chamber through the ventilation plug door, the main valve and the supporting porcelain bottle, so that the arc extinguishing chamber can be maintained. A certain positive pressure prevents the intrusion of external humid air. The vacuum circuit breaker does not need a special air storage cylinder. It is controlled and closed by an electro-pneumatic valve and an electromagnet. As long as the train runs normally, there will be sufficient air supply.

It can be seen that the internal structure of the vacuum circuit breaker is much simpler than that of the air circuit breaker, so the failure rate is lower and the service life is longer. Of course the price is much higher. Generally, vacuum circuit breakers are used in places with high voltage or special environment, because these places have higher requirements for arc extinguishing.

Finally, it should be noted that vacuum circuit breakers cannot currently be used in DC circuits.

china smart circuit breaker, High Quality circuit breakers, smart control circuit breaker, have been widely used at present.