The result can be expressed as a curve function:
100
110
120
130
140
150
160
170
180
190
200
50
60
70
80
90
100
% Nominal Voltage
%
N
o
m
in
a
l
C
u
rr
e
n
t
This means that if the voltage drops, the over-current set point will also drop.
The voltage values for the six points on the curve are fixed; the current values can be adjusted
in the range 50 to 200 %.
Voltage and current % values refer to the nominal settings.
Timer value can be adjusted in the range 0.1 to 10.0 s.
5.2 Inverse time over-current
Formula and settings used
The inverse time over-current is based on IEC 60255 part 151.
The function used is
dependent time characteristic,
and the formula used is:
C
1
G
G
k
TMS
=
t(G)
S
GPC-3 DRH 4189340587 UK
Protections
DEIF A/S
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