7SR21 & 7SR22 Performance Specification
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2.15.3 Operate and Reset Time
Attribute Value
Starter operate time (³ 2 xIs) 20 ms, ± 20 ms
t
op
Operate time
char = IEC-NI,
IEC-VI,
IEC-EI,
IEC-LTI
[ ]
Tm
K
t
Is
I
op
´
-
=
1
a
, ± 5 % or ± 30 ms,
for char = IEC-NI : K = 0.14, a = 0.02
IEC-VI : K = 13.5, a = 1.0
IEC-EI : K = 80.0, a = 2.0
IEC-LTI : K = 120.0, a = 1.0
char = ANSI-MI,
ANSI-VI,
ANSI-EI
[ ]
TmB
A
t
P
Is
I
op
´
ú
ú
û
ù
ê
ê
ë
é
+
-
=
1
, ± 5 % or ± 30 ms,
for char = ANSI-MI : A = 0.0515, B = 0.114, P = 0.02
ANSI-VI : A = 19.61, B = 0.491, P = 2.0
ANSI-EI : A = 28.2, B = 0.1217, P = 2.0
char = DTL
t
d
, ± 1 % or ± 20 ms
Reset time
ANSI DECAYING
[ ]
Tm
R
t
Is
I
res
´
-
=
1
2
, ± 5 % or ± 30 ms,
for char = ANSI-MI : R = 4.85
ANSI-VI : R = 21.6
ANSI-EI : R = 29.1
t
res
t
res
, ± 1 % or ± 20 ms
Repeatability
± 1 % or ± 20 ms
Overshoot time < 40 ms
Disengaging time < 50 ms
Figure 2-2 shows the operate times for the four IEC IDMTL curves with a time multiplier of 1. Figure 2-3 and
Figure 2-4 show the ANSI operate and reset curves respectively. These operate times apply to non-directional
characteristics. Where directional control is applied then the directional element operate time should be added to
give total maximum operating time.
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