A vacuum electrical circuit breaker is made up of two major components – contacts and a breaker. A vacuum contact breaker trips when an earth connection occurs, usually through over/under voltage or a short circuit. A temporary earth circuit breaker allows the electric current from the breaker to be diverted into an alternating current source, usually a battery. The breaker protects the load against short-circuits and overheating. This type of breaker provides protection against power surges and should be installed accordingly. A temporary earth circuit breaker is usually installed in pairs to prevent earth leakage.
A permanent magnet circuit breaker provides protection against high voltage power surges due to overload currents. These breakers are usually used in power applications such as vehicle charging and engine cooling systems. The breakers can also protect against fluctuations in alternating current voltages in transformers.
Temporary high voltage breakers are also called as kick-catch devices and provide protection against faults with high shock and vibration. The kick-catch devices are designed to prevent short circuit and overload currents in power applications. These types of breakers must only be selected if there are no other high-voltage safety devices available. Some high voltage power surge detectors are designed to detect surges exceeding a specified level. In such cases, the vacuum circuit breaker would be used for protection.
The first step is to isolate the potential faults. A good way to determine the possible location of a short circuit or overload current is to flip the switch on the circuit breaker and observe. It’s important to note that this type of equipment is designed to trip at least once. The voltage spike will be very small, which is why you need to be able to isolate the fault. You can do this by connecting a continuity tester to the terminals.
The second step is to look at the characteristics of the vapour emission. A good quality vacuum circuit breaker will produce an arc like pattern which is often called a “chop”. The chop is often black with occasional white areas. If the voltage is more than 8kV, then the vaporisation will be fast and therefore the process will be faster. However, the size of the chop will still depend on the input voltage.
The third step is to determine the possible location of the high-voltage contacts. If the circuit breaker has high dielectric strength, then the current will pass through the contacts and will stop before it gets to the point of disconnection. However, the presence of a low resistance will prevent the current from passing through the contacts. Therefore, the circuit breaker should have high resistance. This will allow the current to get to the contacts faster.
After you have determined the location, the next thing you need to test is the position of the contacts in relation to the high resistance of the circuit breaker. If you are using a non-conductive Teflon-coated contacts, then it should be relatively safe to use a small power transistor attached to a continuity tester to test the circuit breaker. If, however, you use a Teflon-coated contact, then the arc will not pass through the contacts and you will need to use a larger power transistor. You can make this bigger by soldering a larger segment of the Teflon-coated contacts to allow the current to pass through.
Finally, you can check the continuity of the entire system. There are several different types of interrupters available on the market, and they are connected in different ways. Some use high resistance contacts while others use a contact plate that is connected between the high limit and low limit of the circuit breaker.