ABB ConVac Installation And Operation Instruction Manual page 28

28 C O N V A C V A C U U M C O N T A C T O R I N S T A L L A T I O N A N D O P E R A T I O N I N S T R U C T I O N
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7.3.5 maintenance following a short-circuit or
It is foreseen that the ConVac contactor be
protected by fuses and/or by a circuit-breaker. In
any case, the value of a short-circuit can exceed the
threshold of damage to the vacuum interrupters.
After interruption of a maximum short-circuit of
the contactor, inspect all the components and carry
out the repairments or replacements necessary
before putting the Contactor back into service.
Vacuum interrupters
if there is no physical stress and the distance M
exceeds a minimum of 1mm, the interrupters need
to pass a dialectical test before putting into service.
Enclosures
External evidence of deformation of the enclosure
is usually indicative of damage inside it. Extensive
damage will require replacement of the enclosure
parts and of the apparatus contained in it.
Terminals and internal conductors
Replace the damaged parts which show
discoloration, melting or damage caused by
electric arcs. Pay special attention to the moving
parts.
7.4 Repairs
Repairs are necessary if any abnormal signs are
sportified during inspection or maintenance.
Description
Inspection and maintenance of the tulip
Inspection and maintenance of the contact arm
Inspection and maintenance of the fuse and fuse
holder
Inspection and maintenance of the actuating
element
Inspection and maintenance of the fuse automatic
trip strike
Inspection and maintenance of the over-travel of
the contactor
Inspection and maintenance of the plugs and pins
Inspection and maintenance of the auxiliary circuit
Inspection of the power control module
Inspection and maintenance of the operating
mechanism
Inspection and maintenance of the contactor truck
Short-time withstand voltage test
Insulation resistance test
Main circuit resistance test (fuse excluded)
Contactor closing, opening and transmission test
Operation voltage test of the contactor
Mechanical characters test
overload
Replacement with spare parts and accessories
must only be carried out by ABB personnel or by
suitably qualified personnel with appropriate
training.
All the power supply sources must be turned off
and Always work with the contactor open with the
work area insulated and keep safe.
Should maintenance be carried out by the
customer's personnel, responsibility for the
interventions lies with the customer.
While replacing the components which are not
included in the spare part list (as chapter 8), the
repair task should be carried out by ABB service
engineers. Especially:
• Vacuum interrupter and accessories
• Fuse holder
• Operation mechanism
• Truck
7.5 Dismantling and replacing fuses
7.5.1 General requirements
Attention
• All the operations described below must be
carried out by suitably qualified personnel with
in-depth knowledge of the apparatus
• Do not rack the contactor out unless the enclosure
is securely fixed in the switchgear or to a stable
base
• Check that the contactor is open before
proceeding with isolation and its racking-out
from the enclosure
The fuse holder is preset for installation of fuses
with the dimensions and average type of striker
according to DIN Standard and BS Standard.
The fuse holder is always fitted with an automatic
opening device for a fuse blowing. This device
prevents contactor closing when even a single
fuse is missing.
7.5.2 Preliminary operations for fuse replacement
The contactor must be racked out of the enclosure
for replacement of the fuses. Remove the screw on
the left side of the front cover, remove 4 screws
and gaskets as Fig 7c and 7d shows.
Pull the plug out through the window at the
bottom of the front panel (see Fig 7d) then remove
the front panel.