Thermal Overload; Reference - Siemens Argus 7SR21 Technical Manual

7SR21 & 7SR22 Performance Specification
2.9

49 Thermal Overload

2.9.1

Reference

Parameter
Is Overload setting
t
Time constant setting
2.9.2
Operate and Reset Level
Attribute
I Overload level
ol
Reset level
Repeatability
Variation
2.9.3
Operate and Reset Time
Attribute
t Overload trip operate time
op
Repeatability
Unrestricted Page 30 of 68
-10 °C to +55 °C
f - 3 Hz to f + 2 Hz £ 5 %
nom nom
Value
0.10, 0.11... 3 xIn
1, 1.5... 1000 min
Value
100 % Is, ± 5 % or ± 1% In
³ 95 % I
ol
± 1 %
£ 5 %
Value
ì ü
-
2 2
I I
= t ´
P
t ln
í ý
( )
- ´ 2
2
I k I
î þ
B
where I = prior current
P
± 100 ms
© 2013 Siemens Protection Devices Limited
± 5 % o r ± 1 0 0 m s ,
(For I range 0.3 xI to 3 xI
s n
)
n