Starting from nominal voltage, apply a step decrease to the applied voltage to a level below the 47 NPS
voltage setting but above the 47UVG setting such that an NPS overvoltage element operation occurs. Slowly
reduce the applied voltage until the 47 NPS voltage element resets, this can be detected by the General
Pickup LED reset if no other element is operated (this includes any undervoltage element which is not UV
guarded).
Phase Setting (Volts) Tolerence V Element Used
for Test
Blocked Volts Notes
UVG
49 Thermal Overload Protection
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 2
times the Thermal Overload setting. Ensure that the thermal rating of the relay is not exceeded during this
test.
Time Constant (min) Operate Time (s)
1 17.3
2 34.5
3 51.8
4 69
5 86.3
10 173
15 259
20 345
25 432
30 51.8
50 863
100 1726
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 2 times the Overload setting current.
Calculated Operate Time (s)
Measured 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 instru-
ment to be accurate.
Capacity Alarm Setting
Measured
Element Blocking
The thermal element can be blocked by Binary Input Inhibit. This functionality should be checked.
9.9.10
Functional Tests
9.9 Protection Functional Tests
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 473
C53000-G7040-C014-1, Edition 11.2019
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