GE AKR Series Configuration guide

MAINTENANCE MANUAL
(SUPPLEMENT) GEI-86134D
(Supplement to GEK-731 0)
POWENCINCuIT BNEAKENS
TYPE AKR
This manual when used in conjunction with Publication GEK-7310 (Main-
tenance Manual for AKR-3/3A-50 and AKRU-3A-50 breakers) provides main-
tenance instructions on the AKR breaker models and trip devices listed in
Table 1.
IAB]T I
Frame
Size
(Amp)
Breaker Type & Mounting Trip Device Type
Stationarv Drawout ECS ssr
800
AKR-4-30, 30H AKR-4A-30, 3OH X
AKR-5-30, 30H AKR-5A-30. 30H x
AKRU-4A-30* X
AKRU-5A-30* X
1600
AKR-4-50, 50H AKR-4A-50, 50H X
AKR-5-50, 50H AKR-5A-50. 50H X
AKRU-4A'-50* x
AKRU-5A-50* x
2000 AKRT-4-50 AKRT-4A-50 x
AKRT.5-50 AKRT-5A-50 X
* - Integrally fused types
GENERAL @ ETECTRIC

CONTENTS
Introduction
Constructional Diff erences. .
Breaker Ratings
Drawout Breaker Interchangeability
Breaker Maintenance . .
Precautions
Manual Handle Adjustment
ContactMaintenance. . . .
Contact Adjustment:
AKR.3O, -30H, AKRU-30 .
AKR-50, -50H, AKRU-50 .
AKRT-50
Contact Replacement:
AKR-30, -30H, AKRU-30 .
AKR-50, -50H, AKRU-50, AKRT-50. . . .
6
o
6
o
7
I
8
10
10
FusedBreakersAKRu-30, -50 ...... 10
FuseSizesandMountinC.... 10
Special 2500A Fuse. 72
Open Fuse Lockout Device 12
Type SST Overcurrent Trip Device t4
Components 14
TripCharacteristies ......16
Troubleshooting. 77
SST Test Set TAK-TS1. . . . 18
False Tripping (Ground Fault) 19
Replacement of Current Sensors 19
Flux Shift Trip Device 20
Cabling Diagrams. 22
Ground Fault Defeat Cable 23
Type ECS Overcurrent Trip Device 24
Components 24
TripCharacteristics .,,,..25
Cabling Diagram 26
ECS & SST Time-Current Curves 27
fhese inslruclions do nol purporl lo cover oll detoils or voriations in eguipmenl nor to provide for every possrble conlngency lo be mel in conneclion
with instollolion, operolion or moinlenonce. Should further informolion be desired or should porliculor problems orue whrch ore nol covered sufticienlly
for lhe purchoser's purposes, lhe moller should 6e referred lo lhe Generol Eleclric Compony.

Power Circuit Breokers, GEI-86134
MAINTENANCE MANUAT SUPPLEMENT
AKR-30H. Same as the AKR-30 except for modifi-
cauons ln rne rollowlng areas:
a. Arc quenchers.
b. Closing springs.
c. Extra insulation on sha-ft flyweights.
d. Mounts one additional stationary main contact
for a total of four: otherwise the contact struc-
ture is same as AKR-30. See Fie. 6.
NOTE: To uisibly disti.ngtdslt i,t ft,ont tlte
AKR-30, tlte clositzg springs and at,c
qttencher couers of tlte 30H are colored
red.
LOW.VOLTAGE POWER CIRCUIT BREAKERS
TYPES AKR/AKRU.3OI50, AKRT.sO PER TABLE I
INTRODUCTION
The data in this supplement pertains to the new
800A AKR-30 and the 2000A AKRT-5O f rame
oreakers not coveredby the existing AKR/AKRU-50
maintenance manual (publication GEK-7310). In-
formation on the new ECS and SST solid-state trip
devices also is included.
The new breaker models are derivatives of the
1600A frame AKR-50 design. Apart f rom the spe-
c i-f ic const ructional di-f f e rence s identi-f ied bel ow, the
basic AKR-50 framework, mechanism and accessory
devices are substantially common to all versions.
Except for the 800A frame primary stud details,
the external Hx W xD dimensions are identical.
Accordingly, a majority of the AKR-50 in-formation
now in publication GEK-7310 applies equally to the
new types. Therefore, to avoidneedless 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-73i0 as the general. op-
erational information source.
Complementing the above "new" material, this
supplernent includes additional information to ex-
pand and update existing GEK-7310 subject-matter
where appropriate. Examples are revision of the
operating handle adjustment procedure and reduc-
tion of the AKRU-5O minimum fuse size from 8004.
to 450A.
CONSTRUCTIONAL DIFFERENCES
The features which distinguish the new AKR/
AKRT breakersfromthe parent AKR-50 frame size
are listed below. For a detailed parts comparison,
refer to "Renewal Parts Bulletin" GEF-452?.
AKR-30.
a. An entirely new contact structure. Each pole
employs three stationary mains, two stationary
arcingand onemovablecontact arm. See Fig. 5.
Primary studs carry four disconnect fingers per
poie. See Fig. 1.
Two additional opening springs, one at each end
of the main shaft. See Fig. 4.
b.
c. Fig, 1. Rea?' uiew of AKR-50 breaker

GEI-86134, Power Circuit Breokers
AKR-5OH. An AKR-50 with extended short circuit
?ffiEs attaine$-by special arc quenchers, closing
springs and added insulation. euencher tops and
closing springs currry the same red color used on
the AKR-30H.
AKRT-50. A 20004 extension of the 1600A frame
AEF-:$;- M o dif i cations ar e :
a. New and larger upper stud assembly, movable
contact arms and pivot block.
b. Stationary main contacts increased from 6 to g;
otherwise the stationary contacts are identicai
to the AKR-50. See Figs. g and 9.
BREAKER RATINGS
AKR breakers a.reavailable inthree frame sizes
-- 800, 1600 and 2000 amperes. These values re_
present the maximum continuous current capability
of the respective frames. However, each breaker
carries a specificrating whichis determined by the
current.sensor €rmpere rating(or tap setting) of tt"
trip device with which it is equipped.
EXAMPLE: An AKR-5A-3O breaker with SST
sensor tap set on 1004 is rated 100A.
Short cir cuit ratings vary with the applied system
voltage.. OTZ ! V systems they are atso Oependent
upon whether the overcurrent trip device contains
an instantaneous trip element. See lante Z.
TABI.T 2
BREAKTR RAIIIIGS
Frame
Size
(Amperes) Breal<er
Type
Rated
Maximum
Voltage
(60H2 ac)
3{ Short Circuit Rating
(kA RMS Sym)
with
Instantaneous
Trip
Without
Instantaneous
Trip
800
AKR-30 635
508
254
30
30
42
30
30
30
AKR-3OH 635
508
254
42
42
50
42
42
42
1600
AKR-50 635
508
254
42
50
65
42
50
50
AKR-5OH 635
508
254
50
65
65
50
65
65
2000 AKRT.SO 635
508
254
42
50
65
42
50
50
800 AKRU-30 600 200 200
1600 AKRU -50 600 200 200

Power Circuil Breakers, GEI-86134
DRAWOUT BREAKER
INTERCHANGEABILITY
In general, drarvout breakers of the same type
and rating are interchangeable in their equipment
compartments ; drawout breakers of diJf er ent fr ame
sizes are not interchangeable. To prevent inserting
the wrong type breaker into a drawout compartment,
suitable "rejection hardware" is a-ffixed to each
breaker and its compartment. Figure 4 shows a
typical rejection bracket which aligns with a re-
jection pin in the drawout rail (Fig. 3). When the
wrong type breaker is inserted into a compartment
the bracket and pin do not mate, preventing the
breaker from seating itself into the drawout rails.
There is one exception to the above. Breakers
of the same frame size having different short cir-
cuit ratings may be interchanged in one direction
onlv:
a. An AKR-3OH can be inserted into an AKR-30
compartment.
b. An AKR-50H can be inserted into an AKR-50
compartment.
The rejection hardware prevents the converse of
a. and b.
Figure 2 shows the rejection pin and bracket
combinations employed. As determined by its in-
tended breaker type, each drawout c ompartment has
its rejection pin (or pins) installed in one of three
positions (A, B or C front-to-rear) along the slide
rail(s) . Referring to Views 2 and 5, note that only
the AKR-30H and 50H types employtwopins, one in
each slide rail. The other breaker types use a
single pin in the right side TaiL AKRU-3O ard 50
fused breakers use a single bracket, whereas a-ll
nonfused breakers carry two brackets. Use Fig. 2
as a guide for determining the proper breaker
type(s) that will be accepted by any given compart-
ment.
.f r(
ilil
ill ]l
ill ltl
ilt lll
T-n-
AKR.30
o
sa1
'il_ tl
ttt ltl
ilr |ll
ll| ilT
uu
AKR-3OH
(?
n^<
il ltl
lrlr-
tl atl
tt ttl
T-T
AKRU.30
(c,
ffihffi
AKRT.50
@
II TI
ffil--c I neuecrroru
+-il1'-' i"oJ'JT,rn
T----l;l*A J PosrrroNs ffi
IN
AKRU - 50
(6)
Fig. 2. Non-interchangeabi,lity (rej ec ti.on)
hardware arrangements i.n drawout
compartments for breaker Types
AKR -30/s0H/50/50H, AKRT -50 and
AKRU-30/50
z
UJ
F-
F2
<x
o
n
v
- PLAN VIEWS -
KrtJn I sluE
RE.JECTION
PINS IN
SLIDE
RAI LS
R IGHT
SLIDE
RAIL
REJECTION
BRACKETS
MOUNTED ON
BREAK ER
Fig. 3. Slide rail rejection pi.n locations

GEI-86134, Power Circuil Breokers
BREAKER MAINTENANCE
SAFETY PRECAUTIONS
BEFORE INSPECTING OR BEGINNING
ANY XMINTENANCE WORK ON THE
BREAKER, I7: MUST BE DISCONNECTED
FROM ALL VOLTAGE SOURCES, BOTH
POWER AND CONTROL, AND BE IN
THE 'IOPEN" POSITION,
MANUAT HANDTE ADJUST'NENT
On manually - operate d AKR bre ake rs, the closin g
springs may be charged ei.ther by a single 135 de-
gree clockwise handle stroke or up to four multiple
strokes of lesser swing. The following adjustment
procedures should be performed using the single-
stroke method. By so doing, proper multi-stroke
operation is assured.
Referring to Fig. 13 of GEK-?310, the manual
handle adjustment is made via adjustable link (16).
The length of this link is controlled by turning a
double-ended stud in its center. A hex section in
mid-stud can be engaged by an open-end wrench.
When looking down on the breaker, turning the
wrench clockwise lengthens the link. The opposite
motion shortens it. The range of adjustment is 300
degrees. In the confined space available, each
wrench stroke imparts 15 degrees movement. The
best setting is approximately mid-range.
Fig. 4. AKR-SA-30 bt,eaher
Opening spring
Rejection bracket
If the link is too long, the handle stroke cannot
extend the closing spring enough for it to go over
center. In this event, use the maintenance handle
to complete the spring charging. The breaker can
then be closed and opened preparatory to further
shortening of the link.
If the link is too short, one-stroke charging is
not possible. However, more than one stroke will
charge the springs.
CONTACT MAINTENANCE
Breakers subjected to frequent interruption of
high currents may eventually require replacement
of their contacts. The generalrule for determining
need of replacenrent is the loss ofone-haLf or more
of the mass of the contacttip material. Roughening
or light pitting of the contact surface does not indi-
cate loss of ability to carry or interrupt current.
When contacts are replaced, they must be ad-
justed to ensure that the proper a:nount of force is
developed between the movable and stahonary con-
tacts when the breaker is closed. This is called
the "wipe" adjustment. "Wipe" is the distance
throughwhich the stationarycontacts move when the
breaker closes. It is measured between the point
of contact on a stationary contact when the breaker
is open, and the position of the same point when the
breaker is closed. The actual wiping motion is
greater because the contacts over-travel. "Wiping"
imparts a sliding or "scrubbing" action to the con-
tacts.
1.
2.

Power Circuil Breokers, GEI-86134
1. Movable contact arm
2. Stationary main contact
3. Stationary arcing contact
4. Contact spring
5. Arc runner
Fig. 5. AKR/AKRU-S} contact structure
(arc quencher remoued)
The wipe adjustment influence s proper arc trans -
fer during interruption of fault currents . " Transfer' '
of the arc is its forced sequential movement from
the intermediate contacts to the arcing contacts to
the arc runner andfinallyto the arcquencher where
it is dissipated andextinguished. Itis recommended
that contact wipe be checked periodically during
normal maintenance inspections.
CAUTION: BEFORE DOING ANY OF THE
FOLLOWING CONTACT ADJUSTMENT
AND REPLACEMBNT WORK, MECHAN-
ICALLY DISCONNECT THE CLOSING
SPI1/NG FROM THE MECHANISM CAM
SIIAFT. THE BREAKER CAN NOW BE
,,SLOW-CLOSEDI' USING THE MAINTE-
NANCE HANDLE.
CONTACT ADJUSITilENT Types AKR-3O, 3OH
ond AKRU-3O
The contact arrangement of the 800 ampere
frame AKR and AKRU-3O breakers dilfers signi-
ficantly from that of the AKR-50 frame size. Each
pole consists of a single movable contact arm acting
against five stationary contacts, arranged vertically
as shown in Fig. 5. Proceedingfrom top to bottom,
1. Movable contact arm
2. Stationary main contact
3. Stationary arcing contact
Fig. 6. AKR-S1H contact structure
the first two contacts serve as the arcing contacts
and the bottom three are the mains. There are no
intermediate contacts.
The contact assembly for the AKR-30H breaker
employs the same AKR/AKRU-30 configuration, but
adds a fourth stationarv main contact at the bottom.
See Fig. 6.
The following wipe adjustment procedure is ap-
plicable to all AKR-30 types:
1. Open the breaker, remove arc quenchers.
2. Arrange the breaker for slow-closing as de-
scribed on page 15 of GEK-?310.
3. Using the ratcheting maintenance handle,
slow-close the breaker.
4. Se1ect one pole and, using a flat or wire feeler
gage, measure the gap between the top contact and
its pivot stud as shown in Fig. ?. As necessary,
adjust the gap to 0.060 * 0.020 inch by turning the
wipe adjustment stud.
5. Repeat this procedure on the other two poles.
6. Trip the breaker.

GEI-86134, Power Circuit Breokers
ADJUST GAP TO
0.060" t. o.oeo'
WITH BREAKER CLOSED
PIVOT
STUD
STATIONARY
CONTACT
Fig. 7. AKR-30 wipe adjustment - uieoo from
top of breaker
CONTACT ADJUSTMENT Types AKR-SO, sOH
qnd AKRU-SO
Use the follorving procedure toper{orm wipe ad-
justment:
1. Open the breaker, remove arc quenchers.
2. Arrange the breaker forslow-closing, as de-
scribed on page 15 of GEK-7310.
3. Select one pole of the breakerand place a thin
sheet or strip of tough insulating material, such as
myl.ar, over the stationary arcing and intermediate
contacts. This strip should be about two inches
wide and must prevent the arcing and intermediate
contacts from making contact when the breaker is
closed.
4. Using the ratcheting maintenance handle,
slow-close the breaker with the insulation held in
place. Examine the insulation to make sure it
"over-hangs" below the intermediate contacts .
5. Atiach a continuity checker (bell-set or light)
between the upper and lower stud.
6. Facing the breaker, turn the wipe adjustment
stud clockwise until the checker indicates that the
main contacts have parted. An open-end wrench
fits the hex section on the stud.
?. Turn the stud counterclockwiseuntil the main
contacts just touch.
8. From this point, advance the stud counter-
clockwise 270 degrees. This will be 4-1/2 flats.
9. Trip the breaker, remove the insulating strips.
10. Repeatthe above procedure on the other two
poles.
8
CONTACT ADJUST|YIENT lype AKRT-50
The contact structure of this 2000A breaker is
conceptually identical to the 1600A AKR-50 except
that it employs eight stationary main contacts in-
stead of six. Constructionally, however, the upper
stud assembly, movable contact arms and pivot
block are unique to the AKRT-50. See Figs. 8
and 9.
The two movable contact arms are pin-coupled
to a metal driving link whose opposite end is
threaded and screws directly into the insulating
link. This arrangement omits the wrench-operated
wipe adjustment stud provided on the AKR-30 and
-50 frames. Instead, wipe is adjusted by detaching
the driving link from the movable contact arms and
then rotating it with respect to the insulating link.
On the AKRT-50 the proper amount of contact
wipe exists if , on a closed breaker, aII of the sta-
tionary main contacts have moved away from their
stops. This condition can be checked visually by
removing the arc quenchers, closing the breaker
and verifying that all eightstationary main contacts
are "lifted off" their stops. Should wipe adjustment
appear necessary, proceed as follows:
1. Open the breaker.
2. Arrange the breaker for slow-closing as de-
scribed on page 15 of GEK-7310.
3. Selecting one pole, dri-ft out the coupling pin
and detach the drivinE link from the movable con-
tact arms.
4. Screw the driving link completely into the in-
sulating link.
5. Back out the driving tink two and one-half
turns. Exceed this by whatever amount is neces-
sary to properlypositionthe linkwithin the movable
contact arms.
6. Install the coupling pin and retainer rings.
?. Using the maintenance handle, slow-close the
breaker and observe that all eight stationary main
contacts move away from their stops. If this con-
dition is not achieved, open the breaker, againre-
move the coupling pin and back out the driving link
an additional half turn.
8. Reassemble, reclose thebreaker and recheck
wipe.
9. Repeat the above procedure on the other two
poles.

Power Circuif Breokers, GEI-86134
7
Fi,g. 8. AKRT-5) contact structure
1. Movable contact arm
2. StationarY main contact
3. Stationary intermediate contact
4. StationarY arcing contact
5. Driving link
6. Insulating link
I 7. CouPling Pin
DRIVING
LINK
Fig. 9. AKRT-|7 Mouable contact piuot bloch

GEI-86134, Power Circvil Breokers
CONTACT REPIACEIVIENf Types AKR-30, 3OH
ond AKRU-3O
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 marurer employed for the
AKR-50 breakers, i.e., remove and replace the
coupling pin, pivot pin, etc., as described below.
CONTACT REPTACEMENT Types AKR-SO, 50H,
AKRU-50 ond AKRT-SO
Referring to Fig. 17 of GEK-?310, arcing con-
tacts (L) are released by removing the arc runner
(5) andthe arcingcontact pivot (6). When reassem-
bling, make sure that the insulating spacers on the
ends of the arcing contact pin (7) and the insulating
',vashers (B) under the lower arc runner fastening
screws are replaced.
Intermediate (2) and main contacts (3) are re-
moved by disconnecting their springs. The end
pieces on the springs (9) have a small hole for in-
serting a spring puller. While holding the contact,
puII 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. A suitable
puller can be fashioned by forming a hook on the
end of a length of. 1/76-tnch 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 totheir original position.
Tighten the two bolts in the contact arm pivot.
AKRU-3O ond -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 ond Mounting
Table 3 lists the range of fuse sizes available
for thesebreakers. TheClass 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 J fuses rated 300 thru 6004. have one
mounting hole per targ. The 300, 350 and 400A
sizes require copper adapter bars per Fig. 11.
IABIE 3
GT CIT rusTS TOR ATRU BREAI(ERS
NEMA
Fuse
Class
600v
60 Hz
Breaker
Type
AKRU.
-5dl5o-- Ampere
Rating Cat. No.
Melting
Tine-
current
Curves
J
300x
3 50*
400x
GFSB3OO
350
400
GES 8004
ii 450
500
6no
450
500
600
I
I
I
V
L
800
1000
1200
1600
2000
. 800
1000
1200
1600
2000
GES-8005
I
I
I
I
V
Special L 2500 GFgF2SOOAK r.838?832
10
xMounting adapter required - see Fig. 11