Note! If NoI>check or Retrip off is set, only back-up trip can
be used to check set IP>.
13.6.7.2 Checking the residual (earth fault) current operate value
IN>
set
below
IP>
Check the low set IN> current where setting FunctionMode = Current and setting
BuTripMode = 1 out of 4
1. Apply the fault condition, including START of CCRBRF, with a current just
below set IN>Pickup_N.
2. Repeat the fault condition and increase the current in steps until trip appears.
3. Compare the result with the set IN>.
4. Disconnect AC and START input signals.
13.6.7.3 Checking the re-trip and back-up times
The check of the set times can be made in connection with the check of operate
values above.
Choose the applicable function and trip mode, such as FunctionMode = Current
and RetripMode = I> check.
1. Apply the fault condition, including start of CCRBRF, well above the set
current value. Measure time from START of CCRBRF.
2. Check the re-trip t1 and back-up trip times t2 and t3.
In applicable cases, the back-up trip for multi-phase start t2MPh and back-up
trip 2, t2 and t3 can also be checked. To check t2MPh, a two-phase or three-
phase start shall be applied.
3. Disconnect AC and START input signals.
13.6.7.4 Verifying the re-trip mode
Choose the mode below, which corresponds to the actual case.
In the cases below it is assumed that FunctionMode = Current is selected.
Checking the case without re-trip,
RetripMode
=
Retrip Off
1. Set RetripMode = Retrip Off.
2. Apply the fault condition, including start of CCRBRF, well above the set
current value.
3. Verify that no re-trip, but back-up trip is achieved after set time.
4. Disconnect AC and START input signals.
1MRK 504 088-UEN C Section 13
Verifying settings by secondary injection
147
Installation and commissioning manual
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