4.3 Inverse-Time Overcurrent Protection (ANSI 51V)
311
7UM61 Manual
C53000-G1176-C127-3
Trip Time Curves acc. to ANSI
Tolerances
Influencing Variables
As per ANSI/IEEE (see also Figures 4-2 and 4-3)
The trip times for I/I
p
≥ 20 are identical to those for I/I
p
= 20.
Pickup Threshold approx. 1.10 · I
p
Dropout Threshold Approx. 1.05 · I
p
for I
p
/I
N
≥ 0.3
this corresponds to approx. 0,95 · pickup value
Pickup and Dropout
Thresholds I
p
for I
N
= 1 A 1 % of setting value or 10 mA
for I
N
= 5A 5 % of setting value or 50 mA
Pickup Threshold U< 1 % of setting value or 0.5 V
Time for 2 ≤ I/I
p
≤ 20 5 % of reference (calculated) value +1 % current tol-
erance, respectively 40 ms
Auxiliary DC voltage in range
0.8 ≤ U
Aux
/U
AuxN
≤ 1.15
≤ 1%
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