Contact Replacement; Akr-50, -50H, Akru-50, Akrt-50; Fuse Sizes And Mounting - GE AKR-4-30 Maintenance Manual Supplement

GEI-86134, Power Circuit Breakers
CONTACT REPLACEMENT Types AKR-30, 30H
The stationary contacts (arcing and mains) of the
AKR-30 breaker frames are replaced in identical
fashion to that employed for the intermediate and
main stationary contacts of the AKR-50. To do so,
however, it is necessary to first remove the arc
runner by removing its three holding screws.
Replacement of the single movable contact arm
is accomplished in like manner employed for the
AKR-50 breakers, i.e., remove and replace the
coupling pin, pivot pin, etc., as described below.
CONTACT REPLACEMENT Types AKR-50, SOH,
Referring to Fig. 17 of GEK-7310A, arcing con­
tacts (1) are released by removing the arc runner
(5) and the arcing contact pivot (6) . When reassem­
bling, make sure that the insulating spacers on the
ends of the arcing contact pin (7) and the insulating
washers (8) under the lower arc runner fastening
screws are replaced.
Intermediate (2) and main contacts (3) are re­
moved by disconnecting their springs.
pieces on the springs (9) have a small hole for in­
serting a spring puller. While holding the contact,
pull the spring and lift it off the end of the contact.
Replace the contact by holding it in position (inner
end behind the contact stop) while extending and
engaging the spring on the outer end.
NEMA
Fuse
Class
6 00V
60 H z
�
[L
'3pecial
*Mounting adapter required - see Fig. 11
10
and AKRU-30
AKRU-50 and AKRT-50
The end
A suitable
TABLE 3
GE CLF FUSES FOR AKRU BREAKERS
Breaker
Type
Ampere
AKRU-
Rating
30 50
-- 300*
-- 350*
- 400*
-
450
500
600
800
1000
1200
1600
2000
--
2500
--
puller can be fashioned by forming a hook on the
end of a length of 1/16-inch diameter steel wire.
The two movable contact arms (4) are removed
by drifting out pin (10) connecting them to the in­
sulated coupling (11). Right angle tru-arc pliers
are needed to remove and replace the tru-arc re­
tainer on the end of the pin.
Next, remove the fastening screws, washers,
springs and pivot pin from the pivot below. When
replacing the arms ensure that all spacers, springs
and washers are returned to their original position.
Tighten the two bolts in the contact arm pivot.
AKRU-30 and -50 FUSED BREAKERS
Except for the open fuse lockout device and the
integrally-mounted fuses on the upper studs, the
AKRU-30 and -50 breakers are identical to the un­
fused AKR-30 and -50 models. Overcurrent trip
devices are the same for both types.

Fuse Sizes and Mounting

Table 3 lists the range of fuse sizes available
for these breakers. The Class L fuses are mounted
as shown in Fig. 10. Other than the 800A size,
which has a single mounting hole per tang, each L
fuse tang has two holes sized for one-half inch bolts.
Class fuses rated 300 thru 600A have one
J
mounting hole per tang. The 300, 350 and 400A
sizes require copper adapter bars per Fig. 11.
Melting
Time-
Cat. No.
current
Curves
GF8B300
GES-8004
350
400
450
500
600
800
GES-8005
1000
1200
1600
2000
G F9 F2500AK
183B7832
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