4.21
Date Code 20100129
Instruction Manual
SEL-751A Relay
Protection and Logic Functions
Basic Protection
Figure 4.12
U.S. Short-Time Inverse Curve: U5
0.50
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6.00
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15.00
.01
.5 .6 .7 .8
1
.9
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.1
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9
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90
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9
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60
70
90
100
Time in Seconds
Multiples of Pickup
Time in Cycles 60 Hz (50Hz)
3 (2.5)
6 (5)
15 (12.5)
60 (50)
30 (25)
150 (125)
300 (250)
1500 (1250)
600 (500)
3000 (2500)
6000 (5000)
Summary of Contents for 751A
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