118
Intervals for inspection, servicing and repairs
Time intervals for maintenance work to be carried
out always depend on the operating conditions of
the switchgear, and mainly on the mode of
operation, the number of rated and short-circuit
current switching operations, ambient
temperature, pollution etc. We recommend
carrying out the maintenance work at the
intervals below.
9.3 Inspection
Inspection is primarily to carry out a visual check
for grime, corrosion and moisture:
• Effects of high temperature on the main
circuits
• Traces of partial discharge on the insulating
material parts
• Traces of leakage current on the insulating
material parts
• Surfaces of the contact systems
However, inspection must also include correct
mechanical / electrical operation of the following
parts: switching devices, actuating, interlocking,
protection and signalling devices.
Special conditions
On panels with additional ventilation devices.
• Check flap for correct operation, also
• The centrifugal fan (if fitted) does not
require any special maintenance. Its working
life – depending on the service conditions,
and one significant parameter being the
room temperature - is approx. between
20,000 and 30,000 operating hours.
Checking readiness for operation can be carried
out as follows:
• Load-dependent functional test with
controllable primary current supply of the
relative instrument transformer. On current
rise:
-to approx. 70 % of the rated instrument
transformer current, the fan must start.
-to 80 % of the rated instrument
transformer current, the fan must have
reached the required minimum air flow.
Corresponding monitoring (signalling)
by the wind vane with microswitch.
• Basic checking with temporary operation of
the centrifugal fan with an external power
supply of 230 V AC.
• In both cases, check for unimpeded normal
running of the fan and listen for any unusual
bearing noise. Remove any dirt on the fan
rotor.
• Check unimpeded operation of the wind vane
and microswitch by starting the fan several
times.
• The wiring to removable horizontal partition
can be disconnected behind the right-hand
side duct cover. Follow the circuit diagram
and carefully reconnect the wiring again on
completion.
Caution:
With regard to the switching devices, their
separate Instruction manuals should be
followed.
Visual inspection of busbar compartment
• By gaining access from the circuit-breaker
compartment, remove bulkhead 3 (Figure
192), unscrewing 7 x M8 screws.
—
9. Maintenance
Activity
See section Time interval in years According to number of switching operations
Inspection
9.3 4
(1)
As required
(3)
Servicing 9.4 4
(2)
As required
(3)
Repair 9.5 As required As required
(1) For more demanding operating conditions (high ambient temperatures, condensing humidity, active chemical substances or
salty mists in the air) we recommend to shorten the interval suitably
(2) According to the results of the inspection
(3) See the instruction manuals of the switching device
To Next Page
Loading...
Need help?
General
