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4.6 Optional applications
4.6.1. Earthing sw itch for busbar earthing
43).
Earthing the busbar can also be carried out using an
earthing switch (mounted in a box), fitted on the top of
the switchgear.
The earthing switch is mounted on top of the
switchgear, above the busbar compartment.
The mechanism of the earthing switch is mounted
on top of the switchgear, above the low voltage
compartment.
Note:
The busbar earthing switch can be used only with 586
mm height of LV compartment.
W ARNING
Care must be taken w hen operating the busbar
earthing sw itch. Before operating it, make sure
that the busbars are deenergised.
F i g u re 43: Earth i ng sw i tch for b u sb ar earth i n g .
1
Eart hing sw it ch
2
Mec han is m of eart hi ng swit ch
4.6.2. Voltage transformer for busbar measurement
Busbar voltage measurement can also be carried out
using a voltage transformer
mounted on top of the switchgear, above the busbar
compartment.
F i g u re 44: Vol tag e tran sfo rmer.
(Figure
(Figure 44)
detail 1,
4.6.3. Ith Limiters
The sensors consist of micro -switches positioned on
the top of the switchgear near the gas exhaust flaps of
the two power compartments (busbars and circuit -
breaker/cables) for the IEC version. For the ENA
version the sensors are positioned on the rear part on
the vertical flaps of the two power compartments.
The shock wave makes the flaps open and operates
the micro-switches connected to the shunt opening
release of the circuit-breaker. Reaction time is less
than 15 ms. The signal from the microswitch can be
sent directly to the circuit-breaker OFF trigger.
Rapid elimination of the fault, together with the metal
segregation between compartments and the use of
selfextinguishing materials, drastically reduces any
possible damage.
F i g u re 46: Au xi l i ar y I th l i mi ter sw i tch . I t may b e n eces sar y
to mo ve th e au xi l i ary sw i tch es i n to th ei r servi ce p o si ti o n
w h en th e l i ftin g eyeb o l ts h ave b een remo ved .
T he cent re of t he swit ch k nob of t he auxiliar y sw it ch mus t
bena dj ust ed t o t he cent re of t h e pressure re lief f l a p hol e.
1
It h li mit er
2
Pressure rel ief f lap, mad e of st eel she et
21
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