How Do Vacuum Circuit Breakers Work?
- Aug 25, 2017
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Vacuum circuit breakers are often used in high voltage electrical systems to perform the same function as breakers in a home’s electrical panel. The main function of a vacuum circuit breaker is to cut off power to electrical outlets in case of a short circuit or electrical malfunction to allow manual disconnection of circuits so that they can be repaired. A notable feature of vacuum circuit breakers is that they contain evacuated spaces.
To understand how vacuum circuit breakers work, it is important to first understand how normal circuit breakers work. Basic circuit breakers are made of two metal contacts linked together by a spring-loaded mechanism that acts as trip.
The spring-loaded trip mechanism contains a mechanical heat sensor that monitors levels of electricity passing through electrical outlets. The mechanical heat sensor trips off the breaker when temperature levels increase due to overloading electrical conductors.
A magnetic sensor on the spring loaded trip mechanism trips off the breaker in case of a short circuit. The trip mechanism helps to control overload and short circuits by pulling the contacts apart to stop the flow of electricity in the circuit.
Circuit breakers often arc between the contacts for a few microseconds when they trip off pulling the electrical contacts apart. The arcing of the circuit breaker may ionize air and make it conduct electricity or provide a path for the electricity to go past the breaker. This is one of the main reasons why high voltage systems use vacuum circuit breakers because they cannot be ionized providing a path for electricity to go past the breaker. Although vacuum circuit breakers also experience arcing, electricity cannot go past the breaker before the contacts pull away from each other.
As the name suggests, vacuum circuit breakers contain a vacuum between the contacts. The vacuum is just an empty space that does not contain any solid, liquid, or gas. A vacuum is one of the best insulators available. It does not provide room for arcing and electricity cannot pass through a vacuum. Therefore, a vacuum is a suitable arc-extinguishing medium. Some high voltage breakers use a blast of high-pressure air to blow arcs apart. Others are filled with special oil that prevents the arcing. A considerable drawback of the air blast breakers is that they are highly complicated. On the other hand, oil-filled breakers are flammable and are highly toxic in case the oil leaks.
Vacuum circuit breakers, air blast breakers, and oil-filled breakers all perform exceptionally well in transmission lines because these electrical systems do not trip very often. In addition, the three types of breakers require minimal maintenance when used in transmission line applications. However, vacuum circuit breakers perform better than the other two types of breakers in handling line spikes and surges. In addition, vacuum breakers perform much better in high voltage applications that require frequent connection and disconnection of electrical systems.
Circuit breakers are essential electrical components because they help to minimize the effects of temperature and power surges on electrical fixtures.