Estimated service life of vacuum pressure switches

The estimated service life of vacuum pressure switches can be expanded from dimensions such as mechanical life, electrical life, and vacuum life. The following is a detailed introduction for you:

Mechanical life

Mechanical life refers to the number of mechanical actions of a circuit breaker from the date of manufacture. Completing the opening and closing operations is counted as one time, and it can generally reach more than 10,000 times. The mechanical life mainly depends on the service life of the stainless steel bellows. The end of the mechanical life is usually due to the rupture of the bellows. The factors affecting the service life of machinery, apart from manufacturing quality, It also includes the usage environment (such as being affected by chemical corrosion, high temperature, etc.), improper use or adjustment (causing plastic deformation of the bellows), excessive actual stroke during operation or excessive buffering force of the buffer of the operating mechanism, the guiding device not meeting the requirements (shaking when the moving contact rod moves or friction of the bellows), and damage to the bellows due to excessive torque, etc.

Electrical life

Electrical life refers to the number of times the rated short-circuit current is broken or the number of times the rated working current is broken. Whether the electrical life of the arc extinguishing chamber has ended can be determined by the allowable wear thickness of the contacts. When the wear of the contacts reaches the specified value, it indicates that the electrical life of the arc extinguishing chamber has ended. The main factors affecting the electrical life include the arc burning time of the first open phase, the arc burning time of the last open phase, the breaking speed, and the breaking time, etc. Under certain conditions, the arc burning time plays a decisive role. The electrical life of different types of vacuum circuit breakers varies. The electrical life of a vacuum circuit breaker with one opening and one closing rated short-circuit current is 30 to 50 times. Some vacuum circuit breakers with one opening and one closing short-circuit current have an electrical life of only 12 times, but there are also those that can reach over 100 times (such as vacuum circuit breakers with cup-shaped contacts). The electrical life of a vacuum circuit breaker for opening and closing the rated load current is usually 5,000 to 10,000 times, and a few products can reach 20,000 times or more.

Vacuum life

Vacuum life is used to measure whether the internal vacuum degree of a vacuum interrupter remains within the allowable working vacuum range after transportation, storage, installation and operation from the date of manufacture. Whether the vacuum life has come to an end mainly depends on whether the vacuum pressure in the arc extinguishing chamber is above the maximum allowable operating value. The vacuum degree of a vacuum interrupter with good processing technology does not decrease significantly during long-term storage. Generally, the storage life of a vacuum interrupter is longer than 20 years. In actual operation, maintenance can be carried out according to the normal maintenance cycle. The vacuum life of the vacuum switch can be evaluated by using the maintenance data of previous years, and the development trend of vacuum degree can be predicted. Based on the prediction results, the maintenance plan for the later stage can be arranged. In the later stage of the predicted life, key monitoring should be conducted. Online monitoring methods can be adopted to monitor the status parameters of vacuum degree in real time to avoid accidents.

Product case reference

Some vacuum pressure switch products have a relatively high fatigue life. For instance, the fatigue life of some vacuum pressure switches can reach over one million times, and they have good repeatability.