GE Industrial Solutions EntelliGuard 800–2000 A Frames, 240–600 Vac Maintenance Manual - Manual (Page 31)

EntelliGuard™ 800–2000 A Power Circuit Breakers
Chapter 6. Contact Maintenance
21
ATTENTION: Toutes les barriéres isolatrices
doivent être en place avant que le disjoncteur
ne soit replacé en service.
6.3 Back Frame Assembly
The breaker back frame assembly consists of a frame to
which the pole units are mounted. Each pole unit is con-
nected to the breaker main shaft. Typical examples of the
two styles of back frame are shown in Figure 15 and Figure
16. Complete back frame assemblies are available as
renewal parts.
Each pole consists of a separately mounted upper (sta-
tionary) and lower (movable) contact assembly, including
the line and load mounting studs.
6.4 Replacement of Contacts
Contact assemblies are different between the EGS08,
EGF08, and EGH08 frames and the EGX08, EGS16,
EGF16, EGH16, EGS20, and EGF20 frames. The
procedures for contact replacement for each type follow.
Contact Replacement on EGS08, EGF08, and
EGH08 Breakers
Complete upper and lower contact assemblies are avail-
able as renewal parts, as illustrated in Figure 17 and Figure
18. In addition, arcing and main contact springs are
available for the upper contact assemblies. The insulator
link assembly and movable contact springs are available
for the lower contact assemblies.
Use the following procedure to replace a contact assembly,
as illustrated in Figure 19. It is not necessary to separate
the front and back frames.
1. Remove the breaker from its compartment and
place it on a suitable work surface.
2. Remove the primary disconnect from the pole on
which the contact assembly is to be changed, as
described in Section 7.1.
3. Remove the arc chutes and interphase barriers, as
described in Section 6.2.
4. For a lower contact assembly, remove one of the
snap rings from the pin connecting the contact arm
to the breaker main shaft, then slide out the pin.
5. Remove the nut, lock washer, and flat washer from
each of the four studs attaching the contact assem-
bly to the breaker back frame.
6. Slide the contact assembly forward, then lift it out
through the top of the breaker.
Figure 15. Typical back frame assembly, EGS08, EGF08, and EGH08.
Figure 16. Typical back frame assembly, EGX08, EGS16, EGF16,
EGH16, EGS20, and EGF20.