Siemens 7SR12 Argus Manual page 329

Time Constant (mins)
The Thermal State must be in the fully reset condition in order to measure the operate time correctly. This can be
achieved by setting change in the Thermal protection settings menu or by pressing the Test/Reset button when
the Thermal Meter is shown in the Instruments Mode.
Reset the thermal State then apply 2x the Overload Setting current.
Calculated Operate Time (s)
If the Thermal Overload Capacity Alarm is used, this can be tested by monitoring the Thermal Capacity in the
instruments menu. If the Thermal time constant is longer than a few minutes, this can be assessed during the
timing test above. If the Time Constant is less than a few minutes, a lower multiple of current will be required such
that the rate of capacity increase is slowed to allow monitoring of the instrument to be accurate.
Capacity Alarm Setting
2.13.1.1 Element Blocking
The Thermal element can be blocked by Binary Input Inhibit. This functionality should be checked.
Element
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7SR11 & 7SR12 Commissioning and Maintenance Guide
Operate Time (sec)
Measured Operate Time (s)
Measured
BI Inhibits
17.3
34.5
51.8
69
86.3
173
259
345
432
51.8
863
1726
Chapter 6 Page 45 of 72