ABB VD4G-25 Installation And Operating Instructions Manual page 35

M E D I U M V O LTA G E P R O D U C T S
9.3.3. Circuit-breaker pole
The circuit-breaker pole and relative vacuum
interrupter are maintenance-free until the
maximum number of electrical operations for the
type of interrupter is reached. The operating life
of the vacuum interrupter is defined by the sum
of the ultimate currents corresponding to the
specific type of interrupter in accordance with
the indications in the graphs of sect. 7.2.3. Trip
curves: the whole pole must be replaced when
the sum of the ultimate currents is reached.
Notes
Dismantling and replacement of the pole can only be carried out by
ABB personnel or by skilled and specially trained personnel,
particularly as regards the necessary adjustments.
To perform the interrupter vacuum test, move the
circuit-breaker to the withdrawn position with
the opening and closing springs discharged, and
remove from switchgear without dismantling the
circuit-breaker pole. Use:
• a VIDAR vacuum tester, manufactured by
Programma Electric GmbH, Bad Homberg v.d.H.
The following VIDAR tester test values are valid
for the interrupter vacuum test:
Rated voltage of circuit-breaker
15 kV
The test must always be performed with the
circuit-breaker open and the contacts at nominal
distance.
How to conduct the vacuum test for
the interrupter of the circuit-breaker
poles:
• turn off the power supply and
ensure safe conditions in the work
area by complying with the safety
regulations specified in the IEC/
DIN VDE standards;
• open the circuit-breaker;
• earth one terminal of each circuit-
breaker pole;
• connect earth terminal of VIDAR
tester to structure of circuit-
breaker;
• connect high voltage terminal of
VIDAR tester to terminal of circuit-
breaker pole not connected to
earth (L1 phase) and proceed with
the test. Repeat the test for
phases L2 and L3.
Note
The tester connection cables can produce an indication due to the
capacitive effect. In this case the cables must not be removed.
9.4. Repair
Replacement of parts and accessories must only be
carried out by ABB personnel or suitably qualified
and specially trained personnel.
Always work with the circuit-breaker open and
locked so that it cannot be reclosed, with the work
area isolated and in safe conditions.
The spring of the operating mechanism must be
discharged.
All power supply sources must be disconnected and
secured against reclosing during the removal and
installation work.
D.C. test voltage
40 kV
If maintenance is carried out by the
customer's personnel, responsibility for
the interventions remains with the
customer.
Replacement of parts not included in
the "List of spare parts/accessories"
(sect. 11.1.) 11.1) must only be
performed by ABB personnel.
The following parts are not included in
the list:
• complete pole with bushings/
connections
• actuator and transmission system
• closing spring unit
• opening spring
• damper.
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