[Amps] Vacuum Variable Fatigue Failures

[Dave Bowker]

The mechanical life expectancy of any vacuum variable capacitor (independent of manufacturer) is 
dependent upon (1) length of stroke of the bellows, (2) speed of operation or mechanical cycling of 
the bellows and, (3) total number of cycles to be operated.

Generally speaking, capacitors with large diameter bellows and short strokes will exhibit greater 
life expectancy under [equivalent mechanical cycling] than capacitors with small diameter bellows 
and/or longer strokes.

Actual mechanical life expectancy is VERY dependent upon (1) the specific part number capacitor and, 
(2) the specific application, and manufacturers can provide [specific data] for a [specific 
capacitor] in a [specific application].  There is no "universal" answer to your question for every 
hypothetical vacuum variable capacitor ... it is VERY "type and application specific".

You really need to work with a manufacturers applications engineer for your specific requirements.

73, Dave, K1FK
Fort Kent, ME