23
15 Nm
10 Nm
10 Nm
25 Nm
12 Nm
Fig. 11
Checking tightness of the screws
Details regarding overhauling
• When foreseen, cut of the power supply to the spring charging motor
and manually discharge the operating mechanism springs by closing
and opening the circuit-breaker.
• Replace the parts subjected to mechanical stress or stress due to
particular environmental conditions, (contact and ABB service cen-
tre).
Note
These operations can only be carried out by ABB personnel or by skilled
and specially trained personnel.
9.3.3. Circuit-breaker pole
The circuit-breaker pole and relative vacuum interrupter are mainte-
nance-free until the maximum number of electrical operations for the
type of interrupter is reached (see par. 7.2.3. Trip curves).
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 what is indicated in the graphs of par. 7.2.3. Trip curves:
when the sum of the ultimate currents is reached, the whole pole must
be replaced.
Note
Dismantling and replacement of the pole can only be carried out by ABB
personnel or by skilled and specially trained personnel, particularly for
the necessary adjustments.
To carry out the interrupter test without dismantling the circuit-breaker
pole, use:
To check vacuum tightness of the interrupter, the following test values
must be set on the VIDAR tester:
Rated voltage of the circuit-breaker d.c. test voltage
12 kV 40 kV
17.5 kV 40 kV
24 kV 60 kV
The test must always be carried out with the circuit-breaker open with
the contacts at the nominal distance (12 kV ÷ 17.5 kV).
Procedure for testing the degree of vacuum of the interrupter of the
circuit-breaker poles:
– Turn the power supply off and make the working area safe by follow-
ing the safety regulations specified in the IEC/DIN VDE Standards;
– open the circuit-breaker;
– earth a terminal of each circuit-breaker pole;
– connect the earth terminal of the VIDAR tester to the circuit-breaker
structure;
– connect the high voltage terminal of the VIDAR tester to the terminal of
the circuit-breaker pole not connected to earth (L1 phase) and carry
out 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.
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