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Figure 619: Operate time curve based on IDMT characteristic with Minimum operate
time set to 1 second
11.3.1.1
Standard inverse-time characteristics for overvoltage protection
The operate times for the standard overvoltage IDMT curves are defined with the
coefficients A, B, C, D and E.
The inverse operate time can be calculated with the formula:
t s
k A
B
U
U
U
C
D
E
=
⋅
× − >
>
−
+
(Equation 201)
1MRS757644 H
General function block features
620 series
Technical Manual
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