56
MOU NTI NG A N D OPE R ATI ON M A N UA L
I N D O O R A I R S W I TC H - D I S CO N N EC TO R , N A L /N A L F/ V R
19.3 Replacement of fixed contact on the
opening side Fig. 112
Switch-disconnector in open position:
1. Unscrew the two screws 3.1 and lift up the
arcing chamber and the thermal disc 3.4 (for
630 A) while pressing the main contact 3.5
firmly against the hollow insulator 3.8.
2. Lift up the main contact 3.5 by the arcing
contacts 3.6 which penetrate the main
contact. Remove the pressure spring 3.7 and
clean the top of the insulator and the hole,
and blow out the threaded holes (use eye
protection).
3. Attach the new main contact in reverse order
as described above. In case of NAL 12 epoxy
insulators put silicone rubber bumper 3.11
between main contact and insulator as it is
indicated in the drawing.
4. Damaged parts must be replaced:
•
take care that the arcing contacts 3.6 are
correctly placed in the pressure spring 3.7,
•
by mounting the thermal disc 3.4 and the
arcing chamber 3.3, the main contact 3.5
must be pressed firmly against the hollow
insulator 3.8. Attach the whole assembly
by the screws 3.1. For correct torque see
Fig. 112.
•
Check correct position of the arcing
contact and test correct function. Grease
the contact area with ISOFLEX TOPAS NCA
52.
19.4 Replacement of the arcing chamber. Fig. 112
Follow instructions under item „Replacement of
fixed contact on the opening side”.
—
112 Hollow insulator complete
_
WARNING!
These operations shall be carried out by
authorised ABB service only!
_
WARNING!
These operations shall be carried out by
specialists only!
