3 Installation and Commissioning
358
7UM62 Manual
C53000-G1176-C149-3
sues a pickup indication, and, after
address
(1 s on delivery), a
trip indication.
Remove the test resistor.
If the indication „
20 Hz voltage missing
” to be received from the 20 Hz generator
is marshalled to one of the binary inputs, and the delivery setting of this input has been
changed for this purpose, the binary input can be checked as well.
Switch off the supply voltages of the 20 Hz generator.
Feedback „
“ (not masked on delivery).
Indication „
“ (not masked on delivery).
Reconnect the supply voltages of the 20 Hz generator.
If you make use of the possibility to block the 100-% stator earth fault protection by
binary input, the functioning of the input should be checked.
Activate binary input „
“.
Feedback „
“.
Further tests are performed with the machine running (Section 3.4).
Note:
If within the framework of routine tests the band pass 7XT34 is to be checked as well,
short-circuit the earthing or neutral transformer on the secondary side with the ma-
chine standing still, and switch the 20 Hz generator on. Multiply the operational mea-
sured value
I SES
with the transformation ratio of the miniature CT (e.g. 400 A/ 5 A).
The current flow must be higher than 3 A. If the current is noticeably less, the reso-
nance frequency of the band pass has changed. It can be better matched by adding
or removing capacitors (see also operating instructions for the 7 XT33, Order No.
C53000–B1174–C129).
Finally, remove the shorting link and check the galvanic isolation with the operational
measured value
U SEF
.
3.3.9
Checking the DC Voltage/DC Current Circuit
Preparation
Set the DC voltage/DC current protection (address
) to
Block. Relay
.
You can now modify the plant voltage to match the conditions of the intended
application, and verify the response of the 7UM62. A voltage above or below the
threshold voltage (address
) (the appropriate choice is made under the address
) causes the protection to initiate first an alarm “
” (not
marshalled on delivery), and after a time
T DC =
(address
) the alarm “
” (not marshalled on delivery).
The DC voltage protection is then switched operative (address
=
ON
) or – if it will not be used – switched off (
=
OFF
).
