BL1448GE ZP-BL16E TM1700-SERIES
21
3 SYSTEM OVERVIEW
DCM1700
The DCM1700 is equipped with six female DIN con-
nectors on the top grouped pair wise in phase sec-
tions named A, B and C. Each phase section has two
connectors for connection to two breaks.
Below the connectors is the TUNE button.
On the lower end is four cables attached, one with a
female D-SUB connector for connection to (9) on the
TM1700 and three XLR connectors for connection to
the Timing M/R section (4) on TM1700.
Set mode for DCM and tune the
system
The DCM1700 has two modes – Normal mode and
GIS mode. The difference between the two modes
is that the GIS mode is more sensitive. After starting
TM1700 the DCM mode is always reset to normal
mode.
▪
The normal mode shall be used on open air circuit
breakers.
▪ The GIS mode shall be used for GIS circuit breakers but it
can also be used for open air circuit breakers having one
interrupter per phase.
How to enter the GIS mode
1] Keep the TUNE button pressed down for
more than five seconds.
The DCM module will confirm the mode
change by flashing all LEDs simultaneously.
Once the TUNE button is released the tuning will start
in opposite channel order, i.e. beginning with channel
C2 and ending with channel A1.
The reversed tuning order is an indication of that the
DCM1700 is in GIS mode.
To switch back to normal mode
1] Keep the TUNE button pressed down for
more than five seconds.
The DCM will confirm the mode change by
flashing all LEDs simultaneously.
Once the TUNE button is released the tuning will start
beginning with channel A1 and ending with channel C2.
Note If tuning is not successful (LEDs off after
completed tuning) it could hint that the
impedance of the circuit is too low. To fix this
problem the DCM cables between the small
box and the clamps can be spread from each
other.
If you move the position of a DCM cable’s
high frequency part (between small box
and circuit breaker) you need to re-tune the
system. The same applies if ferrites are moved/
added/removed.
Tuning
Once all ferrites are attached the system need to be
tuned. This must be done when the circuit breaker is
in closed position.
1] Check that the circuit breaker is in closed
position.
2] Press the TUNE button shortly.
The tuning is performed automatically chan-
nel by channel and its corresponding LED
flashes. Tuning will take about half a minute
and when finished all channel LEDs, with
cables connected, will be lit.
3] Proceed as a normal time measurement.
DCM capability
Limitations
The technology utilised in DCM is applicable on all
circuit breaker technologies. Still some limitations are
present for certain circuit breaker configurations.
GIS circuit breakers
When timing GIS circuit breakers, attach ferrite clamps
with permeability greater than 1500 on the connec-
tions between ground switch and grounded enclosure
according to figure 4.2-1.
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