DISTRIBUTION SOLUTIONS
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Maintenance operations are aimed at ensuring
trouble-free operation of the apparatus for the
longest possible time.
In accordance with what is specified in the IEC 61208
/ DIN 31 051 Standards, the following operations
must be carried out.
Inspection:
Determination of the actual
conditions
Servicing:
Measures to be taken to maintain the
specification conditions
Repairs:
Measures to be taken to restore the
specification conditions.
9.1. General
Vacuum circuit breakers are characterised by simple,
sturdy construction and long life.
The operating mechanism is maintenance-free for its
whole operating life and only requires functional
inspections (see par. 9.2.2.).
The vacuum interrupters are maintenance-free for
their whole operating life.
Vacuum interruption does not produce harmful
effects even when there are frequent trips at the
rated and short-circuit current.
The servicing interventions and their aim depend on
the environmental conditions, on the sequence of
operations and on the trips under short-circuit.
Notes
For maintenance work, respect the following
Regulations:
• the relative specifications indicated in the
“Standards and Specifications” chapter;
• regulations for safety in the workplace indicated in
the “Putting into service and operations” chapter;
• regulations and specifications of the country where
the apparatus is installed.
The maintenance operations can only be carried out
by trained personnel who respect all the safety
regulations. Furthermore, is recommended that ABB
service personnel should be called in, at least to
check the service performances and for repair work.
During maintenance work, turn the power supply off
and put the apparatus under safe conditions.
9.1.1. Operating life
Operating life expectancy of Vmax vacuum circuit
breakers is as follows:
• vacuum interrupter: up to 30,000 operations
according to the type (see par. 7.2.3. Trip curves);
• actuator: up to 10,000 operations, under normal
operating conditions, according to the type of
circuit breaker and with regular maintenance.
9.2. Inspections and functional
tests
9.2.1. Interruption devices in general
• Carry out regular inspections to verify that the
interruption devices are in good condition.
• Inspection at fixed intervals can be waived when
the apparatus is permanently monitored by
qualified personnel.
• Above all, the checks must include a visual
inspection to find any contamination, traces of
corrosion and electrical discharge phenomena.
• Carry out more frequent inspections when there are
unusual operating conditions (including adverse
climatic conditions) and in the case of
environmental pollution (e.g. heavy contamination
or an atmosphere with aggressive agents).
• Visual examination of the isolating contacts.
Turning the system of contacts alternately is
recommended, in order to keep the internal surface
of the contact areas clean. The contact areas must
be cleaned if there are signs of overheating
(discoloured surface) (also see the “Repairs”
paragraph).
• If any anomalous conditions are found, appropriate
servicing measures must be taken (see the
“Servicing” paragraph).
—
9. Maintenance
Before carrying out any operations,
always make sure that the circuit breaker
is open, with the springs discharged and
that it is not supplied with power
(medium voltage circuit and auxiliary
circuits).
Summary of Contents for Vmax 12
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