Circuit breaker type

There are many types of circuit breaker designs, which can be classified based on voltage (high, medium, low) or other characteristics (such as their arc extinguishing medium and operating mechanism):

1. Oil based circuit breaker: In an oil based circuit breaker, both contacts are immersed in insulating mineral oil. When the circuit breaker trips and the contacts open, the generated arc evaporates oil, which decomposes and forms a compressed hydrogen barrier around the arc. This can prevent further arcing after the circuit is disconnected.

Bulk oil circuit breakers use a larger amount of oil for arc extinguishing and insulation, while minimum oil circuit breakers only use a smaller amount of oil as the interruption medium.

2. Air circuit breaker: Air circuit breakers can also be used for low voltage and certain medium voltage circuits. They work by increasing the arc voltage, which is the minimum voltage required to maintain the arc. Once it reaches a point higher than the power supply voltage, the arc will collapse.

These arc extinguishing systems are divided into two types: ordinary air and blower. According to the design, they can achieve arc interruption by cooling the arc plasma, increasing the length that the arc must pass through, or dividing a single arc into multiple arcs.

3. SF6 circuit breakers: The name of these circuit breakers comes from sulfur hexafluoride (SF6), which is an excellent insulator that absorbs negative ions. The chamber around the contact is filled with gas, and the arc causes a chemical reaction, increasing the arc voltage. SF6 circuit breakers typically use one, two, or four circuit breakers, depending on the voltage level they need to handle. These are usually not considered environmentally friendly because SF6 is a greenhouse gas.

4. Vacuum circuit breaker: Although it has been in existence for over half a century, vacuum circuit breakers are still under development. Due to their compact size, high reliability, and low maintenance costs, they are almost exclusively used for medium voltage circuits. The arc interruption occurs in a steel chamber with symmetrically placed ceramic insulators, where a high vacuum degree is maintained.