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500-8384.9 • Version 11 • Installation and Operating Instructions • 8DJH
Mode of operation
Fig. 17:
Principle of gas monitoring with ready-
for-service indicator
1
Switchgear vessel (filled with insulating
gas)
2
Measurement box
3
Magnetic coupling
4
Red indicator: not ready for service
5
Green indicator: ready for service
For the ready-for-service indicator, a gas-tight measurement box is installed inside the
switchgear vessel.
A coupling magnet, which is fitted to the bottom end of the measurement box, transmits its
position to an armature outside the switchgear vessel through the non-magnetizable switchgear
vessel (magnetic coupling). This armature moves the ready-for-service indicator at the operating
front of the panel.
While changes in the gas density during the loss of gas, which are decisive for the dielectric
strength, are displayed, changes in the relative gas pressure resulting from temperature and
external pressure variations are not. The gas in the measurement box has the same temperature
as that in the switchgear vessel.
The same pressure change in both gas volumes compensates for the effect of temperature.
▪ The switchgear operates perfectly in a range between the rated filling level of 150 kPa and
the minimum functional level of 130 kPa.
▪
If the gas pressure falls below 130 kPa
, the switchgear must not be operated anymore.
The ready-for-service indicator changes from the green area to the red area ("not ready for
service").
▪ If the ready-for-service indicator changes from the green area to the red area, the signaling
switch (option) changes its switching state.
Tab. 13:
Functional principle of the signaling switch
State of the ready-for-service indicator in the green
area
State of the ready-for-service indicator in the red
area
NC contact
1
open and NO contact
2
closed
NC contact
1
closed and NO contact
2
open
3.13 Short-circuit indicators and earth-fault indicators
The panels can optionally be equipped with short-circuit indicators or earth-fault indicators in
different designs.
Operating instructions and information on equipment features are available in the respective
manufacturing documentation.
3.14 Low-voltage compartment (option)
▪ Overall height: 200, 400, 600 or 900 mm
▪ Installation on the panel is possible per feeder
▪ Customer-specific equipping of the low-voltage compartment
Содержание 8DJH
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