21.0 Replacement Of Parts In Nal/Vr 36 Kv; Replacement Of Contact Knives - ABB NAL Series Installation And Operating Instructions Manual

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M O U N T I N G A N D O P E R AT I O N M A N U A L I N D O O R A I R S W I TC H - D I S C O N N E C TO R , N A L / N A L F/ V R
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21.0 Replacement of parts in NAL/VR
36 kV
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116 Detached draw bar
a
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117 Detached contact screw
b

21.1 Replacement of contact knives

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WARNING!
These operations shall be carried out by
authorised ABB service only!
1. Disconnect the switch-disconnector. When
A-mechanism is fitted, the opening spring
must NOT be charged.
2. The draw bar is detached from the crank arm
of the operating shaft, see Fig. 116.
3. The contact screw is detached and the
contact knives are removed, see Fig.117.
4. Replacement contact knifes are lubricated
with ISOFLEX TOPAS NCA 52 and mounted to
the contact block with the contact screw.
5. Check that the contact knives can move
easily and operate correctly over the
opposite contacts.
6. Before the drawbar is connected to the crank
arm of the operating shaft, see Fig. 116
ensure that the auxiliary knives run easily in
the individual arc extinguishing chambers,
and that the main knives make proper
contact.
7. Put contact grease on the main contacts
before the first test operation. The contact
position is adjusted by the eccentric bolt on
the operating shaft. It can also be adjusted
by adjusting the support insulator.