Power Circuit Breakers, GEI-86134
MAINTENANCE MANUAL SUPPLEMENT
LOW-VOLTAGE POWER CIRCUIT BREAKERS
TYPES AKR/AKRU-30/50, AKRT-50 PER TABLE
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INTRODUCTION
The data in this supplement pertains to the new
800A AKR-30 and
the 2000A AKRT-50 frame
breakers not covered by the ex isting AKR/AKRU-50
maintenance manual (publication GEK-7310A) . In
formation on the new ECS and SST solid-state trip
devices also is included.
The new breaker models are derivatives of the
16 00A frame AKR-50 design. Apart from the spe
cific constructional differences identified below, the
basic AKR-50 framework, mechanism and accessory
devices are substantially common to all versions.
Ex cept for the 800A frame primary stud details,
the ex ternal H x
W
x D dimensions are identical.
Accordingly, a majority of the AKR-50 information
now in publication GEK-7310A applies equally to the
new types. Therefore, to avoid needless repetition,
the scope of this supplement is confined principally
to that descriptive and instructional material unique
to the new models. Unless noted to the contrary,
or otherwise discussed herein, the user should
continue to employ GEK-7310A as the general, op
erational information source.
Complementing the above "new" material, this
supplement includes additional information to ex
pand and updateex istingGEK-7310A subject-matter
where appropriate. Ex amples are revision of the
operating handle adjustment procedure and reduc
tion of the AKRU-50 minimum fuse size from 800A
to 450A.
CONSTRUCTIONAL DIFFERENCES
The features which distinguish the new AKR/
AKRT breakers from the parent AKR-50 frame size
are listed below. For a detailed parts comparison,
refer to "Renewal Parts Bulletin" GEF -4527.
AKR-30.
a. An entirely new contact structure.
Each pole
employs three stationary mains, two stationary
arcing and one movable contact arm. See Fig. 5.
b. Primary studs carry four disconnect fingers per
pole. See Fig. 1.
c. Two additional opening springs, one at each end
of the main shaft.
See Fig. 4.
AKR-30H. Same as the AKR-30 ex cept for modifi
cations in the following areas:
a. Arc quenchers.
b. Closing springs.
c. Ex tra insulation on shaft flyweights.
d. Mounts one additional stationary main contact
for a total of four; otherwise the contact struc
ture is same as AKR-30. See Fig. 6 .
NOTE:
To visibly distinguish it from the
AKR-30, the closing springs and arc
quencher covers of the 30H are colored
red.
Fig. 1. Rear view of AKR-30 breaker
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