Siemens 7SR12 Argus - Thermal Overload; Reference; Operate and Reset Level; Operate and Reset Time

7SR11 & 7SR12 Performance Specification
©2017 Siemens Protection Devices Limited Chapter 3 Page 25 of 56
2.7 49 Thermal Overload
2.7.1 Reference
Parameter Value
Is
Overload setting
1.0 xIn
i
Applied Current (for operate time) 1.2 to 10 x Is
τ
Time constant setting 1, 10, 100, 1000 min
2.7.2 Operate and Reset Level
Attribute Value
I
ol
Overload level
100 % Is, ± 5 % or ± 1% In
Reset level
≥ 95 % I
ol
Repeatability
± 1 %
Variation
-10 °C to +55 °C
≤ 5 %
f
nom
± 5 %
≤ 5 %
2.7.3 Operate and Reset Time
Attribute Value
t
op
Overload trip operate time
( )






×−
−
×τ=
2
2
2
P
2
I
II
ln
B
Ik
t
where I
P
= prior current
± 5 % absolute or ± 100ms,
(Is: 0.3 – 3 x In)
Repeatability
± 100ms
Note:- Fastest operate time is at 10 xIs