Megger TM1700 Series, Руководство пользователя

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TM1700-sEriEs ZP-BL16E BL1448GE
3 sysTEM OVErViEW
Note
A Ferrite kit is available as an optional acces-
sory. Art.no. XB-40090
if it is not possible to mount ferrites on the grounding
links/shunts of the insulated ground switch, connect
an additional 20-meter ground cable between ground
switch and stationary ground. Then remove the links/
shunts between ground switch and enclosure accord-
ing to 4.2-1 and 4.2-3. if it is not possible to increase
the impedance of the grounds the DCM technology
will fail.
Fig. 4.2-1
Fig. 4.2-2
Fig. 4.2-3
Circuit breakers with parallel resistor
contacts
The parallel resistor contact itself is not detected by
DCM timing. Only the main contact is detected. Paral-
lel contacts with resistors from 10 Ohm and above is
not interfering with the main contact DCM timing.
Graphite nozzle breakers
DCM timing is carried out the same way as conven-
tional timing, i.e. closing time can be either graphite-
graphite or graphite-silver transition, depending on
the moving contact alignment. Due to this DCM, and
all other timing, is not suitable for timing graphite
nozzle breakers. instead you shall use DrM together
with CABA Local sW (version r04A and later) for a
specific evaluation.
Long distance between accessible DCM cable
connection points
some circuit breakers, e.g. certain models of dead
tank breakers, may have longer distance between
the accessible connection points than the maximum
spread of the DCM cable (4 meters). Thus, you need
to extend the DCM cable in such case. However, if
you extend the DCM cable it is not guaranteed that
the DCM works properly
❿ TRIG IN
Used for external trig of the unit. starts an initiated
measuring sequence from a remote destination by
either a contact make or break or voltage signal. set-
tings are made from CABA Local or CABA Win.
⓫ Mains input
Always use the power cord supplied with the unit.
⓬ Protective conductor terminal
Connection to earth (ground), see “1.2 safety instruc-
tions”.