Citadel 2.0 - Instruction Manual - page:
34
IM
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C
2.0
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/2
5
/3
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Vacuum Interrupters Life Expectation Curve - ANSI C 37.09 breakers
The life expectancy of vacuum interrupters is a function of the number of interruptions
and magnitude of current interrupted.
FIGURE: 8
a
b
c
c
a
Breaking current (rms value) in kA
Rated operating sequences: O-300ms-CO-3min-CO
Numbers of oper
ating c
ycles
b
Breakers must have vacuum interrupter assemblies replaced when they achieve maximum-life
curve limits, when erosion dot is no longer visible or if micro-ohm readings are greater than 100%
above specified nominal.
V A C U U M I N T E R R U P T E R / O P E R A T O R