ABB VM1-T Manual page 16

V M 1 -T - VACUUM CIRCUIT BREAKER
16
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7. Maintenance
7.3.3
The breaker pole with the vacuum interrupter is
maintenancefree up to the permissible number of
operating cycles as sent down in section 10.1.3.
The working life of the vacuum interrupter is defined
by the sum current limit corresponding to the
equipment data in individual cases in accordance
with section 10.1.3:
• When the sum current limit is reached, the
complete breaker poles are to be replaced.
Note:
Dismantling and replacement of the breaker poles
should only be performed by the ABB after-sales
service or adequately trained specialist staff, in
particular with regard to the necessity for precise
setting.
The following equipment, for example, can be used
to check the vacuum (without dismantling the
circuit breaker):
• VIDAR vacuum tester, from
Programma Electric GmbH
Bad Homburg v.d.H., Germany
The following test values have to be set for checking
of the internal interrupter chamber pressure with
the VIDAR vacuum tester:
Rated voltage of the circuit breaker
12 kV
17.5 kV
24 kV
Testing is to be performed at the rated contact
distance in the OFF condition.
Procedure for vacuum interrupter testing for
stationary mounted switching devices:
• Isolate and secure the working area in accordance
with the Safety Regulations to DIN VDE / IEC.
• Open the VM1-T circuit breaker.
• Earth all poles of the VM1-T circuit breaker on one
side.
• Connect the earthed test lead of the VIDAR
vacuum tester conductively to the station earth.
• Connect the high voltage test lead of the VIDAR
vacuum tester with phase L1 of the unearthed pole
side and test the vacuum interrupter chamber with
the circuit breaker contact gap open. Repeat for
phases L2 and L3.
Note:
Connected cables may lead to a "defective"
indication on the vacuum tester as a result of their
cable capacitance. In such cases, the cables are to
be removed.
Breaker pole
DC test voltage
40 kV
40 kV
60 kV
7.4 Repair
7.4.1 Repair of surface damage
Circuit breaker part in general
• Sheet steel parts, painted:
- Remove rust, e.g. with a wire brush.
- Grind off paint coat and degrease.
- Apply anti-rust primer and top coat.
- Use a top coat in the standard colour RAL 7035
or the relevant special colour.
• Sheet steel parts with aluminium-zinc surfaces
and chromated functional parts:
- Remove white rust, with a wire brush or cleaning
pad (e.g. Scotch-Brite, white).
- Remove loosely adhering particles with a dry
cloth.
- Apply zinc spray or zinc dust primer.
• Functional parts, phosphated:
- Remove rust, with a wire brush or cleaning pad
(e.g. Scotch-Brite, white).
- Clean with a dry cloth.
- Grease with Isoflex Topas NB 52 lubricant.
Withdrawable circuit breaker part in general:
• Where required, regrease or thoroughly clean slide
plates and bearings in the panel and regrease
them with Isoflex NB 52 lubricant.
Remove the contact system for thoroughly
cleaning as described below (Figures 9/23 and
9/24:
- Slide the two inner annular tension springs 34.2
facing the breaker pole to a position beside the
other two outer annual tension springs, thus
releasing contact system 34.1, and remove the
contact system from contact arm 34.
- The contact pin of the contact system and the
slot on the contact arm are to be cleaned and
greased.
- Fit the contact system back to front on the thin
end of arbor 39, and slide it forwards onto the
thicker part of the shank.
- Fit arbor 39 onto the relevant contact arm 34,
slide the contact system 34.1 over onto the
contact arm, and withdraw the arbor.
- Check all contact fingers and annular tension
springs for perfect fit.
Note:
The set installation position of contact arms 34
must not be changed by the improper use of force.
7.4.2 Replacement of components
• Only remove and reassemble circuit breaker parts
and accessories when the breaker has been
switched off and the working area is to be isolated
and secured against reclosing.