Siemens 7SR224 Technical Manual page 254

2.6.3.2 ANSI Reset
If the element is configured as an ANSI characteristic, it may have a reset delay applied. If ANSI reset is selected
for an IEC characteristic element, the reset will be instantaneous.
ANSI reset times from operated condition to fully reset are as follows for zero applied current and TM = 1.0. The
reset curve characteristic type and TM is defined by the operating characteristic.
Curve
ANSI-MI
ANSI-VI
ANSI-EI
Apply current in the following sequence, a) 2x setting for a time to ensure element operation, b) Zero current for
the reset time above (xTM), c) 2x setting for a time to ensure element operation. Check that the second operation
(c) is similar to the first (a) and in line with the expected operate time for the element at this current level.
Repeat the test with the reset time (b) reduced to 50% of the previous value. Ensure that the second operate time
(c) is 50% of the first (a) operate time.
Operate time Reset time
(expected) (calculated)
Check correct indication, trip output, alarm contacts, waveform record.
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Fully operated to reset with Zero current applied & TM=1 (secs)
Operate time 50% Reset
(measured)
(calculated)
First test (c)
7SR224 Argus Commissioning & Maintenance Guide
4.85
21.6
29.1
50% operate
Time time
(calculated)
50% operate
time
(measured)
Second Test (c)
Chapter 6 Page 28 of 73