ABB VD4 12, Installation And Service Instructions Manual

41

9.3.3. Circuit-breaker pole

The circuit-breaker pole and relative vacuum in-

terrupter is maintenance-free up to the maximum

number of electrical operations foreseen for the

type of interrupter (see par. 7.2.3.).

The operating life of the vacuum interrupter is

defined by the sum of the ultimate currents cor-

responding to the specific type of interrupter in

accordance with what is indicated in the diagrams

of par. 7.2.3: when the sum of the ultimate cur-

rents is reached, the complete pole must be re-

placed.

Note

Dismantling and replacement of the operating

mechanism (snap-on box) can only be carried

out by ABB personnel or suitably qualified and

specially trained personnel, especially for the

necessary adjustments.

To carry out the interrupter test without disman-

tling the circuit-breaker pole, use:

– the VIDAR vacuum tester, of the Programma

Electric GmbH, Bad Homberg v.d.H. company.

To check vacuum tightness of the interrupter, the

following test values must be set on the VIDAR

tester:

Rated circuit-breaker

DC test voltage

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 to 24 kV).

Procedure for testing the degree of vacuum of

the interrupter of the circuit-breaker poles:

– insulate the working area and make it safe  by

following the safety rules specified in the  IEC/

DIN VDE Standards;

– open the circuit-breaker;

– earth a terminal of each circuit-breaker pole;

– connect the earthed 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 test connection cables may produce an in-

dication due to the capacitive effect. In this case

the cables must not be removed.

9.4. Repairs

Replacement of spare parts and accessories

must only be carried out by ABB personnel or

suitably qualified and specially trained person-

nel.

Always work with the circuit-breaker open and

locked so that it cannot be closed again, with

the work area insulated and made safe.

The operating mechanism springs must be dis-

charged.

All power supply sources must be disconnected

and made safe against any reclosing during re-

moval and installation work.

Should the maintenance be carried out

by the customer’s personnel, respon-

sibility for the interventions remains

with the customer.

The replacement of parts not included

in the list “List of spare parts/accesso-

ries” (par. 12.1.) must only be carried

out by ABB personnel. In particular:

– complete pole with bushings/connec-

tions

– actuator and transmission system

– set of closing springs

– opening spring

– shock absorber.