ABB VD4 Series Instruction Manual - page 31
Instruction manual 534/01 | VD4 Vacuum-circuit-breaker 31
8
Maintenance
Maintenance serves to ensure trouble-free operation and
achieve the longest possible work-ing life of the switchgear.
In accordance with DIN 31 051 / IEC 61208 it comprises the
following closely related activities:
Inspection:
Determination of the actual condition
Servicing:
Preservation of a functional condition
Repair:
Measures to restore the functional condition
8.1
General
Vacuum circuit-breakers are characterized by their simple and
robust construction. They have a long life expectancy. Their
operating mechanisms have a low maintenance requirement,
and the interrupters are maintenance-free during their working
life. There is no adverse effect on the vacuum, even from
frequent switching of operating and short-circuit currents.
The servicing intervals and scope are determined by environ-
mental influences, the switching sequen ces and number of
short-circuit breaking operations.
Note:
The following must be observed for all maintenance work:
- The relevant specifications in section “Standards and
specifications“
- Notes on safety at work in section “Commis-sioning/
Operation“
- Standards and specifications in the country of installation.
Maintenance work may only be performed by fully trained
personnel, observing all the relevant safety regulations. It is
recommended that ABB after-sales service personnel should
be called in, at least during the performance of servicing and
repair work.
While the work is in progress, all supply voltage sources must
also be disconnected and secured to prevent reconnection.
Note:
In order to prevent accidents (particularly injury to hands!)
extreme care should be taken during all repair work on the
operating mechanism, especially with front plate removed.
The spiral spring in the spring energy storage mechanism,
for instance, retains a basic tension which is independent of
the charging and discharging processes during switching,
so as to ensure correct function. This spring energy can be
inadvertently released if work is performed incorrectly on the
spring mechanism!
8.1.1 Service-life
Typical life-expectancies for VD4 circuit-breakers:
- Vacuum interrupter chambers: Up to 30,000 switching
cycles, (see section “Permissible numbers of switching
cycles“)
- Device: Up to 30,000 cycles under normal operating condi-
tions, depending on breaker type, and given regularly and
conscientiously performed maintenance
- Withdrawable assembly: With careful operation and appro-
priately performed inspection work, up to 1000 movement
operations can be achieved.
See also IEC 60298
The service life data fundamentally apply to all components
which are not directly influenced by the operator.
Components operated manually (movement of the withdrawa-
ble part, etc.) may deviate.
8.2
Inspection and functional testing
8.2.1 Switching devices in general
- The proper condition of the switching device is to be veri-
fied by regular inspection.
- The checks are to be performed in accordance with BGV
A3 standard.
- Inspection at fixed intervals may be waived if the switch-
gear is permanently monitored by a qualified personnel.
- The checks first and foremost comprise visual examinati-
on for contamination, corrosion, moisture and discharge
phenomena.
- In unusual operating conditions (including adverse climatic
conditions) and/or special environmental pollutions (e.g.
heavy contamination and aggressive atmosphere), inspec-
tion may also be necessary at shorter intervals.
- Visual checking of the isolating contact system. We
recommend to turn alternately the contact system in order
to clean the inner contact points of the contact system.
- The contact points should be cleaned if signs of unper-
minable overheating (discoloured surface) are visible (see
section “Repair“)
- If an incorrect condition is found, appropriate servicing
measures are to be initiated.
8.2.2 Stored-energy spring mechanism
Functional testing of the operating mechanism is to be
performed:
- after 5000 operating cycles or
- during servicing work as set out in section „Inspection,
switching devices in general“.
Prior to functional testing, switch the breaker off and
- move it into the test position (withdrawable breaker) or
- isolate the outgoing feeder (with stationary mounted
breakers).