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6 DISTRIBUTION SOLUTION EK6 – MEDIUM VOLTAGE EARTHING SWITCH 12…40,5 KV – 25–50 KA
The speed of the snap-action closing operation
is independent on speed of operation. The earth-
ing switches are supplied as kits with a pre-as-
sembled active part and corresponding earthing
contacts supplied separately. Correct installation
of these parts in a switchgear panel results in
a functioning earthing switch. Routine tests ac-
cording to IEC 62271-102 has to be carried out
at site accordingly.
Earthing switches of series EK6 have three pairs
of earthing blades which are located on the oper-
ating shaft and are freely movable. The pairs
of earthing blades are electrically connected
to each other by a short-circuiting bridge and
to earth potential at the bearing brackets by
two stranded copper conductors. Driver levers
and toggle springs located between the bearing
brackets are used to transmit the force during
the switching process. During switching
process the blades are pushed into the fixed
contacts within a short-time period. Fixing the
active part on a torsionally rigid base frame
of switchgear panel wall or crossbeam provides
it with the necessary stability.
The particular earthing contacts have to
be bolted to the conductor bars which are
supported on suitable insulating parts, e.g.
dielectric insulators or current transformers.
Position of blades and contacts have to be ad-
justed exactly based on dimensional drawings
shown below. Axial distance between each
blade and contact has major effect on speed
of switching and proper function of earth switch.
The earthing switch has a snap action closing
mechanism which is independent of the rotation
of the drive shaft. The switching speed and
torque achieved in this process are independent
of the speed of the operating mechanism.
During opening process, the toggle springs have
no effect on the speed of contact separation.
Operation is possible with a ring lever with bevel
gear and suitable manual or motorized operating
mechanism with the required torque moment
for the exact type of earth switch. Required
operating angle of lever has to be 180.
Operating mechanism and shaft is located
on right side as standard for UniGear panel.
Shaft located on left side has to be specified
during ordering process if requested.
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01 EK6 12kV
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02 EK6 36kV
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03 Earthing contact
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Structure and function
Earthing switches of series EK6 are determined for indoor installation
and conform to the requirements of IEC 62271-102. They are fitted
with snap-action operating mechanisms for positive high-speed
closing and sufficiently dimensioned to conduct the rated short-
circuit making current when closed under load.
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