Whether the vacuum degree of the vacuum interrupter is good or not is directly related to the insulation performance and arc-extinguishing performance of the vacuum switch. Therefore, in the regular maintenance of the product, the test of the vacuum degree is very important. If the vacuum degree is reduced, it is easy to cause accidents. So how to test specifically? Here are some common methods:
1. Observation method
This is a simple test method, that is, the staff observes and discriminates the vacuum interrupter in operation. The method is to observe the color change of the getter film. Generally, the brightness of the film is very high, which indicates that the degree of vacuum is good. It is milky white, then the vacuum degree is poor, but this method will not work for the ceramic shell.
2. AC withstand voltage method
This method is a commonly used method in the past, and it is a power frequency withstand voltage method, but this method can only judge whether the vacuum degree meets the requirements, and cannot give specific conclusions on the actual situation of the vacuum degree. Any reaction changes, the test result is unqualified, it can be found that the vacuum degree has been reduced to a great extent.
3. Electromagnetic method
This method is more accurate and reliable to monitor the vacuum degree. The specific monitoring method is to apply a magnetic field between the contacts, then apply a pulse voltage for a period of time, and calculate the vacuum degree data through the magnitude of the current.
In addition to the observation method, the AC withstand voltage test, and the electromagnetic method described above, there is also the spark meter method, but this method has limited usage and is only suitable for vacuum interrupters made of glass.