DOC. MIE91093 Rev. 1.34 Page 21 of 145
instantaneous threshold; else, if there is only one contact, it is
impossible to be measured..
. Select the Maintained test control mode:
Test control > Fault injection > Maintained (RET)
. Press ON from the trip current above.
. Slowly decrease the current; as the relay resets, pressing the
multi-function knob, the reset value can be saved.
1.1.5. Trip and drop-off timing
Now we can measure trip timings, following the I-t curve with
as many points as desired. First thing, restore the Maintained
fault injection, as follows
Test control > Fault injection > Maintained (RET)
Then select the NO or NC level for the relay trip contact:
Timer start/stop > STOP > EXT > Clean (Voltage) > NO
(NC) ESC
Now, press ON and pre-adjust the first test current: as the
relay trips, don’t save test result; go OFF. Select ON+TIME: as
the relay trips, test goes OFF; pressing the multi-function knob
tripping values can be saved. The TRIP LED (43) turns on and
parameters at trip are displayed until ON or ON+TIME are
selected. Confirm save results pressing the multi-function
knob, and proceed with other test currents, until all points to
be tested are measured.
Now we can measure the drop-off timing. First thing, select
the NC or NO level for the relay reset contact:
Timer start/stop > STOP > EXT > Clean (Voltage) > NC
(NO) ESC
Now, press ON and pre-adjust the current. Select OFF+TIME:
as the relay resets, pressing the multi-function knob drop-off
values can be saved. Confirm save results pressing the multi-
function knob, and proceed.
1.2 OVER AND UNDER VOLTAGE
1.2.1. Introduction
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