Schweitzer Engineering Laboratories SEL-751 - Figure 5.22 Breaker Monitor Accumulates 10 Percent Wear

5.24
SEL-751 Relay Instruction Manual Date Code 20170927
Metering and Monitoring
Breaker Monitor
0 Percent to 10 Percent Breaker Wear
Refer to Figure 5.22. 7.0 kA is interrupted 20 times (20 close/open operations
= 20 – 0), pushing the breaker maintenance curve from the 0 percent wear
level to the 10 percent wear level.
Compare the 100 percent and 10 percent curves and note that for a given
current value, the 10 percent curve has only 1/10 of the close/open operations
of the 100 percent curve.
Figure 5.22 Breaker Monitor Accumulates 10 Percent Wear
10,000
100%
10%
1000
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100
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.5
Number of Close/Open Operations
kA Interrupted per Operation