4.25
Date Code 20100129
Instruction Manual
SEL-751A Relay
Protection and Logic Functions
Basic Protection
Figure 4.16
IEC Long-Time Inverse Curve: C4
0.20
0.10
0.05
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
.7
.6
.5
.1
.9
.8
1
.4
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.5
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.9
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3
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Time in Seconds
Multiples of Pickup
Time in Cycles 60 Hz (50Hz)
30 (25)
60 (50)
150 (125)
300 (250)
3000 (2500)
600 (500)
1500 (1250)
6000 (5000)
15000 (12500)
30000 (25000)
60000 (50000)
Summary of Contents for 751A
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