ABB V-Contact VSC Series Installation And Service Instructions Manual page 32

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7.4. Servicing following a short-circuit
or overload
General
It is foreseen that the VSC contactor be pro-
tected by power fuses and/or by a circuit-
breaker. In any case, the value of a short-cir-
cuit can exceed the threshold of damage to the
vacuum bottles.
After interruption of a short-circuit at the maxi-
mum rated MVA of the contactor, put the cause
of the fault right, inspect all the apparatus and
carry out the repairs or replacements neces-
sary before putting the apparatus back into
service.
Make sure that all the spare parts (when re-
quired) are suitable for the application.
In case of any doubts, please contact ABB.
Have a complete check of the contac-
tor carried out by ABB personnel af-
ter 1,000,000 operations or 10 years
of operation.
Contact ABB Service Assistance.
Vacuum interrupters
A dielectric test by itself cannot be confirma-
tion that the interrupters have to be put back
into service after a fault. However, if there is no
physical sign of stress and if the distance M
exceeds a minimum of 0.5 mm, the interrupt-
ers can be tested dielectrically as mentioned
in point 3 of table 4.
Should this test also be positive, it is reason-
able to put the interrupters back into service
following a fault.
Enclosures
External evidence of deformation of the enclo-
sure is usually indicative of damage inside it.
Extensive damage will require replacement of
the enclosure parts and of the apparatus con-
tained in it.
Terminals and internal conductors
Replace the damaged parts which show
discolouration, melting or damage caused by
electric arcs. Pay special attention to the mov-
ing parts.
M [mm]
Fig. 16
Carry out the "Checking" procedures indicated
in par. 6. of this manual before putting the ap-
paratus back into service..
7.5. Repairs
Replacement with spare parts and accessories
must only be carried out by ABB personnel or
by suitably qualified personnel with appropri-
ate training.
All the power supply sources must be turned
off and the capacitor must be discharged.
Always work with the contactor open, with the
work area insulated and made safe.
Should maintenance be carried out by
!
the customer's personnel, responsi-
bility for the interventions lies with the
customer.
VSC 7.2 VSC 12
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