Service And Maintenance; Cleaning; Switch-Disconnector In Service - ABB NAL Series Installation And Operating Instructions Manual

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18.0 Service and maintenance

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WARNING!
The use of any type of alcohol-based
cleaners is strictly forbidden. This results
in weakening of the mechanical properties
of tension rods and can cause cracking of
them. For more info – see last pages!

18.1 Cleaning

After maintenance the switch-disconnector must
be cleaned before being put into service. Strong
solvents and alcoholic fluids must not be used.
For cleaning, water with soap can only be used.
After cleaning, the contact area of the main
blades and the fixed contacts must be greased,
type ISOFLEX TOPAS NCA 52. If the switch-
disconnector is placed in a very humid and
polluted area, which will reduce the tracking
resistance, it is recommended to polish the
insulators and insulated components with Silicon
Type DC200 Fluid 100 cst.

18.2 Switch-disconnector in service

The switch-disconnector's real maintenance
interval depends on both environmental
conditions and on number and characteristic of
on/off operations. The proceeding specified
maintenance schemes refer to normal indoor
operating conditions only.
All installation work with full respect to
requirements of proper installation of switch-
disconnector in substation/panel and cable/
busbar connection to switch-disconnector
terminals, station design, location selection,
ground preparation and maintenance, must be
performed in a professional way to keep the
installation in good condition throughout it's
lifetime.
When special operating conditions occur the
service intervals and service scope should be
adjusted individually preventing the switch to be
stressed over its performance limits. The switch-
disconnectors with design class suitable for
special operating conditions (like NAL -H) should
be used.
After a possible short-circuit, overall quality
checks (mechanical and electrical) is requested.
The replacement of damaged parts or complete
replacement should be done in line with the NAL
conditions observed. Special attention needs to
be focused on the main contacts. The quality of
the silver coated contacts shall be such that a
continuous layer of coating material remains on
the contact area. Otherwise affected
components need to be replaced for new ones. If
fuses were applied to the switch they must be
replaced. The proper coordination with the NALF
switch-fuse combination requires fuse selection
from Reference list of fuses (see 24.0) according
to ABB instruction.
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