Dynamic characteristics of high-speed operated, long-stroke bellows for vacuum interrupters

The authors observed and analyzed the dynamic characteristics of long-stroke stainless steel bellows for a vacuum interrupter when it is extended and contracted at high speeds. The dimensions of bellows tested are: outer diameter 85 mm, inner diameter 62 mm, number of folds 44 and 55. They are tested at contraction speeds of 4 m/s and extension speeds of 2 m/s and 1 m/s. It was found that increasing the number of folds on the bellows does not necessarily prolong its life, and that the bellows should be designed so that the ratio of operation stroke and free length of bellows falls in the range between 0.3 and 0.4