DEMA 400 Series User Manual page 49

Universal trip time delay formula is given above, while special curve parameters are given on
the below table.
t Trip delay (s).
A A constant for the characteristic (s).
I Momentary current (A).
Is Set current threshold (A).
α A constant for the characteristic (-).
B A constant for the characteristic (s).
TMS Time Multiplier Setting (-).
Curve Type
SA Semic
Semiconductor Protection
SB DI
Definite İnverse
SC CO2
Short Time Inverse
SD CO8
Long Time Inverse
SE CO-C3H
Standard Inverse
The image below shows the custom trip delay curves with TMS = 1.00. TMS can be set in the
range (0.025 - 3.2) for any protection function
Tripping Type Formula
35500 s
t= [ ] ×TMS
I
6 -1
( )
I
s
2.96875 s
t= [ + 1.96875] ×TMS
I
2.3
-1
( )
I
s
0.0092 s
t= [ +0.008 s] ×TMS
I
( )-1
I
s
21 s
t= +0.720 s
2
I
( ) -1
I
[
s
1.81 s
t= +0.68 s
1.05
I
( ) -1
I
[
s
49
Reset Time Setting Range
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DMT (0.04 - 100) s
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RTMS (0.025 - 3.2)
DMT (0.04 - 100) s
×TMS
or
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RTMS (0.025 - 3.2)
DMT (0.04 - 100) s
×TMS
or
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RTMS (0.025 - 3.2)
= ������ ( 0.04 − 100 ) ��
= ������ ( 0.04 − 100 ) ��