Schweitzer Engineering Laboratories SEL-311C - Figure 9.8 I. E. C. Class C Curve (Extremely Inverse): C3

9.13
Date Code 20060320 Instruction Manual SEL-311C Relay
Setting the Relay
Time-Overcurrent Curves
Figure 9.8 I. E. C. Class C Curve (Extremely Inverse): C3
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.5 .6 .7 .8 .9 1
.02
.03
.04
.05
.09
.07
.06
.08
.1
.2
.3
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.5
.7
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1
423 56789
10
40
20
30
70
50
60
80
90
100
80
10
2
3
6
4
5
7
9
8
20
50
30
40
60
70
100
90
0.20
0.10
0.05
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
Time in Seconds
Multiples of Pickup
Time in Cycles 60 Hz (50Hz)
3 (2.5)
6 (5)
15 (12.5)
30 (25)
60 (50)
600 (500)
150 (125)
300 (250)
1500 (1250)
3000 (2500)
6000 (5000)