Inspection Of The Contact System - GE Gerapid 2607 User Manual

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Fig. 42 Inspection of the arc chute

6.1.4 Inspection of the contact system

Pay attention to the warnings, Section 1!
A) Remove the arc chute
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[Fig. 41]. Loosen the clamping screws (3) and (4), using
SW 5 hexagon wrench and take off the arch chute (1)
from the adapter (2).
B) Remove the arc chute adapter
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[Fig. 43]. For dismantling the arc chute adapter loosen
and pull out the four upright screws (1) using SW5 tool.
Pay attention that no screws or washers fall inside the
breaker !
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[Fig. 43]. Draw aside and lift off both parings of
adapter (2). Then pull out two protective walls (3).
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Fig. 43 Adapter and protective walls
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C) Check the protective walls
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Fig. 44 Checking the contact system
D) Check the arc runners
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E) Check the pre-arcing contact
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G) Install the adapter
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H) Install the arc chute
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Design and specifications are subject to change without notice
[Fig. 44]. The material burn out on the protective walls
(5) shall not exceed 1mm [0,04in] at any place.
[Fig. 44]. The arc runners should not be burned more
30% of its total cross section. Pay particular attention
to the area around arc runner bend (3) and at contact
point with pre-arcing contact (2).
[Fig. 44]. Wear of the pre-arcing contact (1) must not
exceed 2mm [0,08in] of its depth. Replace the pre-
arcing contact in that case. If the burn out exceeds
4mm [0,16in], it might lead to major contact system's
failure.
F) Check the main contacts
[Fig. 44]. The main contacts (4) shell not shown any
particular signs of material erosion, since the arc is ig-
nited between the pre-arcing contacts. It means, that
for rated and overload currents there is no erosion of
main contacts.
Erosion of main contacts can take place only in case
of excessively worn, highly burned pre-arcing contact
or during very high short circuit currents. In that case
wear must not exceed 1mm [0,04in].
[Fig. 43]. Install the two protective walls (3). Use new
ones if necessary. Install two parings of adapter (2)
and tighten screws (1) use 5Nm [44lbf*in].
[Fig. 41]. Put in arc chute (1) into adapter (2).
[Fig. 41]. Tighten front- and backside connections of
the arc runners (3), including lock washer; use 10Nm
[88lbf*in].
[Fig. 41]. Tighten front- and backside of the arc chute
connections (4), including flat washers; use 5Nm
[44lbf*in].
01/2008