V< Threshold And Drop-Off - ISA T1000 PLUS User Manual

DOC. MIE91093 Rev. 1.34 Page 30 of 145
. Set the "Automatic save at trip" function, as follows.
Test control > Save > Confirm at trip > ESC
. Set the timer with the following selections:
Timer start/stop > START > INT (RET)
STOP > EXT > Clean (Voltage) (RET)
Edge ESC
NOTE: stop clean or voltage according to the relay trip contact
connections.
1.3.3. V< Threshold and drop-off
The first session is finding threshold V<. Select ON; increase
the DC voltage to VN. The relay will reset; do not confirm the
value. Now slowly reduce the voltage; as the relay trips,
confirm save results pressing the multi-function knob, and
proceed.
NOTE: stored value is the voltage as relay trips. This
corresponds to the relay threshold only if the current did not
change very much while the relay timing elapsed. If threshold
measurement was not good because you were moving too
fast, do not confirm test results and repeat the test.
Next, we find the drop-off threshold for V<. From the voltage
above, slowly increase the voltage; as the relay resets,
pressing the multi-function knob tripping values can be saved.
NOTE: stored value is the voltage as the relay resets. This
corresponds to the relay drop-off only if the current did not
change very much while the relay timing elapsed; however,
reset timing is usually very short, so current does not change
very much at release, and the measurement is accurate.