If you own or rent your own home, you likely already understand a little bit about circuit breakers. When the power gets cut off during a storm, or after plugging in a new electronic into an outlet whose circuit is at full capacity, the solution is typically to check your home's fuse box for a flipped circuit. Flipping it back to it's 'on' position will restore the current, and return electricity to the part of your home that was affected. So what are the mechanics at play behind this?
A circuit breaker, as the name implies, is a device that cuts the flow of electricity within a circuit when triggered. In the most basic terms, it contains two metal contacts, as well as a spring operated mechanism and a sensor that can detect sudden surges or gradual increases to the current flowing through the system. During normal operation, the metal contacts are touching, which allows current to flow. Once a sensor hits a designated threshold, the spring operated mechanism pulls the contacts apart, effectively interrupting the circuit and stopping current from flowing.
Circuit breakers are put in place in order to prevent damage to a system due to excessive current, typically as a result of some kind of system fault such as an overload or short circuit. They are also utilized during maintenance, cutting off power so that the electrical system can be worked on safely. For homes and other smaller scale circuits, standard air circuit breakers work well. However, they do risk the chance of ionizing the air inside the breaker, which continues to allow current to flow for a very short amount of time after being tripped. For this reason, medium to high voltage electrical systems require the use of vacuum circuit breakers. These devices create a vacuum, essentially meaning they contain no air or other particles, which prevents ionization of the air and removes the possibility of allowing electricity a path to flow through.
When researching different models of vacuum circuit breakers, it's important to look into their specifications. Each one is rated for a different voltage, will have different breaking currents, and may abide by different electrical standards. They are also specialized for different applications, such as power distribution, generators, and even railway applications. If you'd like to learn more about vacuum circuit breakers, many of these manufacturers provide details on their purpose and application on their websites, and can be a great place to start learning!