ABB
43
Uniswitch Operation and
Maintenance Manual
UNIS14GB 05-02
5.3 Inspection
General Where necessary, the working area must be isolated and secured
before inspection against reconnection in accordance with the “Safety
Regulations” specified by IEC and appropriate national standards.
Correct condition of the switchgear should be monitored by regular
inspections. Under normal operating conditions, inspection should be
carried out once every four years by specially trained professional
electricians.
Instructions The following inspections should be carried out:
• visually check for grime, corrosion and moisture
• check for effects of high temperature on main circuits
• check for traces of partial discharge on insulating material parts
• check for traces of leaking current on insulating material parts
• visually check the surfaces of contact systems
o Contact points should be cleaned if signs of overheating
(discolored surface) are visible.
! We recommend to turn the contact system of the
withdrawable part back and forth in order to clean the
inner contact points of the contact system.
Inspection must also include correct mechanical/electrical operation of
the following:
• switching devices
With regard to the switching devices, their separate instruction manual
should be followed.
• actuating devices
• interlocking devices
• protection devices
• signaling devices
• switchgear accessories and auxiliary devices (e.g. storage batteries)
No partial discharge must occur on the surfaces of equipment at
operating voltage. This can, for example, be detected by characteristic
noises, a clearly perceptible smell of ozone, or visible glowing in the
dark.
Under abnormal operating conditions (including adverse climatic
conditions) and/or special environmental stresses (heavy pollution and
aggressive atmosphere, among others), inspection may be necessary
at shorter intervals
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