9.2.1 Special conditions
•
On panels with ventilation devices, check flap
for correct operation
•
With regard to the switching devices, their
separate instruction manual should be
followed
•
Check all 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
•
Visually check the contact system. The contact
points should be cleaned if signs of
overheating (discoloured surface) are visible
(see 9.4 Repairs)
•
If any irregular conditions are detected, then
relative repair measures must be taken
Caution!
At no stage should a tool (eg Allen Key or
Ratchet Spanner) be used to check the
tightness of the Bolt, as the seal will be
broken and the adjustment disturbed.
9.2.2 Vacuum Interrupters of V7/ZVC
Check that the red mark is vertical as shown
(either 6 o’clock or 12 o’clock).
With the contactor in the closed position
measure the gap between the bolt head and
the washer. When the gap is zero, the vacuum
interrupters need to be replaced. The replacement
can only be done in the ABB factory.
A dielectric test by itself cannot be confirmation
that the interrupters have to be put back into
service after a fault.
Carry out a voltage test with the contacts open
at 25.6 kV-50 Hz for one minute. If there is a
discharge during the test, the interrupter must be
replaced because this type of phenomenon
corresponds to deterioration in the degree of
vacuum. In case of need, contact ABB Service.
Should this test also be positive, it is reasonable
to put the interrupters back into service following
a fault.
9.3 Servicing
If, during the course of an inspection in accordance
with 9.2 Inspection, the need for cleaning measure
has been established, proceed as follows:
•
Where necessary, the working area must be
switched off and secured against
reconnection in accordance with the “Safety
Regulations” specified by IEC and appropriate
national standards before cleaning
•
Clean the surfaces in general:
- Weakly adhering dry dust deposits: with a
soft dry cloth
- More strongly adherent grime: with mildly
alkaline household cleanser or with
ETHANOL F 25 M
•
Clean insulating surfaces and conductive
components with ETHANOL F 25 M
•
Wipe down after cleaning, using clean water,
and dry properly
•
Should partial discharges occur as a result of
condensation, application of a thin silicone film
on the surface concerned is often effective as
a temporary remedy. It is advisable to ask the
ABB after-sales service department for advice
regarding permanent solutions to this type of
unusual problem
M A I N T E N A N C E
47
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9/1 View from right
hand side of the
truck
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9/1