An air switch, also known as an air circuit breaker, is a type of circuit breaker. It is a switch that automatically breaks whenever the current in a circuit exceeds the rated current. The air switch is a very important electrical appliance in low-voltage distribution networks and power-drag systems, combining control and multiple protection functions. Here we explain "The difference between air and vacuum circuit breakers".

How to distinguish between air(ACB) and vacuum circuit breakers(VCB)?

The so-called "air" and "vacuum", initially refers to its different arc extinguishing device, air circuit breakers are relying on arc extinguishing Shan device, by elongating the arc, and then rely on air cooling to extinguish the arc (what is the arc?). Well, it's an arc or an electric spark). A vacuum breaker, on the other hand, relies on a vacuum to extinguish the arc, with a vacuum bubble inside.

This leads to the second difference. Whereas air circuit breakers rely on compressed air to perform during the opening or closing action, vacuum circuit breakers, due to their highly vacuum-like nature, dictate that they cannot use an air storage chamber, so they rely on electric valves and solenoids to control the opening and closing of the circuit.

Air circuit breaker action before the storage cylinder to be filled with sufficient compressed air; starting valve d cavity filled with compressed air; another small amount of compressed air through the ventilation plug door, the main valve, supporting the porcelain bottle into the interrupter chamber, so that the interrupter chamber to maintain a certain positive pressure to prevent the intrusion of external moisture air. The vacuum circuit breaker will not need special storage air cylinder, it is controlled by electric air valve and solenoid to close, as long as the train is running normally, there will be sufficient air supply.

As can be seen, the internal structure of a vacuum circuit breaker is much simpler than that of an air circuit breaker, resulting in a lower failure rate and longer life. Of course the price is also much higher. Generally vacuum circuit breakers are used in high voltage or more special environments where the requirements for interrupting the arc are higher.