The vacuum level test of the vacuum circuit breaker is very important. Once the vacuum is broken, the arc cannot be extinguished, causing the circuit breaker to explode. The vacuum test method is as follows:

1. Visual inspection method. If the vacuum interrupter is a glass shell, it can be judged by the color of the suction film applied to the inner wall. The vacuum degree is good, and the film is mirror-shaped, and the vacuum degree is good, the film is mirror-shaped. It is milky white when the vacuum degree is different. Although this method is not very accurate, it can be used as a reference.

2. Power frequency withstand voltage method. In the open state, the power frequency test voltage is carried out between the fractures, and it can withstand more than 10s under the power frequency withstand voltage, indicating that the vacuum degree is good. If the current also increases in the process of voltage increase, it is considered unqualified if it exceeds 5A. Of course, breakdown in the process of resistance to compression is unacceptable.

3. Magnetron discharge method. Measurements are carried out using special test instruments, in which one or several high-voltage pulses are added between the contacts, with a pulse width of tens to hundreds of milliseconds, and a synchronous pulse current passes through the magnetic field coil to produce the same pulsed magnetic field to measure high voltage. Vacuum.

The relevant countries stipulate that the vacuum degree is 0.066Pa to be qualified. If it is close to or below 0.6, it is not qualified and should be updated. When the vacuum level is greatly reduced, the test cycle should be shortened and updated according to the development.

4. Special vacuum tester for measurement. At present, due to the development of science and technology, complete sets of measuring instruments for various types of vacuum circuit breakers have been manufactured, and quantitative measurement without disassembly has been realized on site. By means of quantitative measurement, it is not only possible to measure whether the vacuum degree of the vacuum switch is within the normal range, but more importantly, for some vacuum switches with fast leakage speed, the life of the vacuum switch can be roughly inferred by comparing the results of previous years. It really serves the purpose of preventing accidents.