Those who have been in contact with circuit breakers know that if you just go to a hardware store and buy a switch, I’m afraid you are not unfamiliar with the nouns of mini circuit breakers, air switches, plastic shell breakers, and frame breakers. What do these nouns mean? Is there any connection between them?
Circuit breakers are the general name of all the nouns mentioned above. A circuit breaker is a kind of mechanical switch that can connect, load and break the current in the circuit. Note that there are two main characteristics of the circuit breaker, one is the ability to cut off the current, the other is the internal arc extinguishing device. Some switches, such as knife switches, can cut off the current without interrupter, so they can not be called circuit breakers.
There are many classifications of circuit breakers, and the most widely mentioned ones are classified according to insulation medium and current. According to the insulating medium, it can be divided into air circuit breaker and vacuum circuit breaker. According to the current, it is divided into mini circuit breaker, plastic case circuit breaker and frame type (universal type) circuit breaker.
ACB or air switch is also called air circuit breaker. The opposite is the vacuum circuit breaker.
The difference between the two is that the arc extinguishing device of the air circuit breaker relies on lengthening the arc (the arc is the spark) and then relying on the air cooling to extinguish the arc. Vacuum circuit breakers rely on internal vacuum interrupters.
Vacuum circuit breakers
Which is better and which is not good, I am afraid it can be judged from the name itself. The air circuit breaker is exposed to air for a long time due to its internal structure, and the structure of the arc extinguishing device is complex. It is easy to be affected by temperature and humidity and air erosion. The vacuum circuit breaker has simple internal structure and completely isolated from the air. Therefore, the failure rate and life span are all better than those of air circuit breakers. Of course, the price of vacuum circuit breakers is also very impressive.
We often use air switches, so the word “air switch” is often heard that the word “vacuum switch” is not even known to a lot of ordinary users.
Miniature circuit breakers, moulded case circuit breakers and frame circuit breakers
According to the current, it can be divided into micro circuit breaker (MCB), plastic case circuit breaker (PCCB) and frame circuit breaker (universal circuit breaker). Note that these three belong to the category of low voltage circuit breakers.
A miniature circuit breaker with a current of no more than 63A. A plastic shell circuit breaker with a current of no more than 600A. Frame circuit breaker with a current of no more than 4000A.
Due to the difference in current size, the size of the internal structure is also different, resulting in a larger or smaller size of the shape.
In addition, there are many changes in the way of operation. The operation mode of general micro circuit breaker and moulded case circuit breaker is rather monotonous. The frame circuit breaker is more difficult to machine because of its large shape and simple mechanical switching. Therefore, various operating modes such as electromagnet, electric motor and handle are introduced.