ABB EK6 - Maintenance

10 DISTRIBUTION SOLUTION EK6 – MEDIUM VOLTAGE EARTHING SWITCH 12…40,5 KV – 25–50 KA
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Maintenance
Earthing switches – type EK6
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01 Auxiliary contract
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02 Drive Shaft
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03 Earthing blades
and tongue
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01
Cleaning the kinematics to prevent faults on the
signaling contacts
• Carry out a visual inspection of the kinematics
and check for any presence of dirt, humidity and
signs of corrosion on the moving parts.
• Manually check correct changeover of the earth-
ing switch signaling contacts (picture 1).
• Remove any deposits of dust using a dry cloth
that does not leave any deposits on the treated
surfaces (do not use woolen cloths).
• If necessary, grease the mechanical moving
parts by applying a thin layer of mechanical
grease for moving parts. Include earthing
blades and tongue (picture 3).
• Carry out a visual inspection on the toothed
wheel and pinion shaft (picture 2) and check any
presence of dirt, humidity and signs of corro-
sion on the moving parts.
Inspection and periodic maintenance
Closing of the earth switch several times under
load conditions makes inspection and possibly
maintenance necessary. (Two close operations
at 100 % of the rated short-circuit making current
are allowed as maximum). The electrical and
mechanical functions of the switch must not
be adversely affected, and only slight contact
welding is permissible. The pairs of earthing
blades and the earthing contacts should be
replaced if necessary.
Otherwise, it is advisable to carry out inspection
and maintenance of the earthing switches at
appropriate intervals together with the switch-
board, particularly in exceptional operating
conditions and/or under adverse environmental
influences such as pollution and aggressive air:
• Check whether the operating mechanism
functions smoothly and easily.
• Carry out general visual inspection for
the condition of mechanical fasteners, dirt,
moisture and corrosion.
• Remove any dust deposits on insulating parts
with a dry, non-fraying cloth (do not use clean-
ing wool).
• Regrease the mechanically movable parts and
contacts (applying grease thinly) using Isoflex
Topas NB52 lubricant.
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02
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03