Siemens 3AH3 Instruction Manual page 36

Figure 21: Typical vacuum interrupter contact life curves
Permissible operating cycles
36
100,000
50,000
20,000
10,000
5,000
2,000
1,000
500
200
100
50
20
10
1 2
Breaking current (symmetrical value)
Note: Right-hand vertical segment of curve is located at the maximum
symmetrical interrupting current rating of the circuit breaker, as indicated in
Table 3.
Load graph "A" vacuum interrupter type VS-17006
Load graph "C" vacuum interrupter type VS-25008
Load graph "E" vacuum interrupter type VS-17040
C
20 25 31.5
5 10
A E
40 50 100