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7SR11 & 7SR12 Commissioning and Maintenance Guide
2.13 Thermal Overload (49)
I
L1
I
L2
I
L3
Voltage Inputs:
Current Inputs:
Disable:
Map Pickup LED:
The current can be applied from a 3P balanced supply or phase by phase from a 1P supply. Alternatively the 3
phase current inputs can be connected in series and injected simultaneously from a single 1P source.
The Thermal Overload Setting and Time Constant Setting can be considered together to calculate the operating
time for a particular applied current.
The following table lists operate times for a range of Time Constant Settings for an applied current of 2x the
Thermal Overload setting. Ensure that the thermal rating of the relay is not exceeded during this test.
©2017 Siemens Protection Devices Limited
37
(x2)
(I
)
A
37
(x2)
(I
)
B
37
(x2)
(I
)
C
46
BC
I
(I
)
4
G
27
V
(V
)
59
L1
A
(x4)
27
V
(V
)
59
L2
B
(x4)
27
V
(V
)
59
L3
C
(x4)
Figure 2-14
n/a
I
(I
), I
(I
), I
L1
A
L2
B
51, 50, 37, 50CBF
49Alarm
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
46
67/
67/
60
60
NPS
50N
51N
CTS
VTS
(x2)
(x4)
(x4)
67/
67/
50BF
50
51
SEF
SEF
NOTE: The use of some
functions are mutually exclusive
47
81
59N
(x2)
(x4)
(x2)
Optional
79
Thermal Overload
(I
),
L3
C
7SR12
81
HBL
51c
2
81
HBL
51c
2
81
HBL
51c
2
64H
Note:
Example shows
Voltage Config =
Van, Vbn, Vcn
74
T/
CCS
Chapter 6 Page 44 of 72
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