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

Power Circuit Breokers, GEI-86134
IH Ttbicat mounting fm class ttLttfuse
on'AXnU-TT and -50 breakers
Fip. 11. Mounting for 300, 350 and 400A Cl'ass J
" fuses on AKRU-3? breaksrs
11

GEI-86134, Power Circuit Breokers
la
Speciol 250OA Fuse for AKRU-SO
This fuse provides a meltingtime-current char-
acteristic that coordinates with 16004. trip devices.
Compared physically with a 25004 NEMA Class L
fuse, the special fuse is more compact (shorter) ;
its tangs are specially configured and offset to
achieve the required pole-to-pole fuse spacing; a
special primary di sc onnect assembly m ounts direcUy
on the outboard tang of the fuse. Considering their
unique mounting provisions, when replacing these
fuses the following procedure should be adhered to
(Refer to Fig. 12):
1. Remove the primary disconnect assembly
from the fuse taag, accomplishedby first loosening
the two keys (2) via their holding screw and pulling
them upward and out. After the keys are removed,
pull the disconnect assembly off the end of the fuse
tang.
NOTE: This remoual does not disturb the
disconnectts clamping force adjustment,
2. Remove the upper barrier (4) .
3 . Detach the inboard end of the fuse by remov-
ing the turo 1/2 inch - 13 bolts. A ratchet and
socket with a short extension will be required.
t2
Fi.g. 12. AKRU-|0 breaker with special 25004 fuse
1. Special 25004 Fuse
2. Disconnect Key
3. Heat Sink
4. Upper Barrier
5. Primary Disconnect
4. Remove the heat sink (3).
5. Remove the fuse.
6. [rstall the new fuse by reversing the dis-
assembly procedure. Ensure that the mating faces
of the fuse and heat sirk are clean.
CAUTION: WHEN REPIACING THE
FUSE IN THE LET-T POLE (FRONT
VIEW) OF THE BREAKER, NOTE PAR-
TICUIARLY THAT THIS FUSE 15
MOUNTED DIFFERENTLY THAN THE
OTHER TWO FUS,DS. AS SHOWN IN
FIG. 14, FOR THIS PHASE THE FUSE
IS ROTATED 180 DEGREES ABOT]T I7:S
AXIS SO THAT ITS INBOARD TANG IS
POSITIONED BENEATH THE BREAKER
STUD. fUtS rAtr,C tS OFFSET WITH
RESPECT TO THE OPPOSITE END (SEE
FIG. 13, SO THAT ROTATING THE FUSE
DOES NOT ALTER THE POSITION OF
THE PRIMARY DISCONNECT.
Open Fuse Lockout Device
Refer to GEK-7310, page 31.

Power Chcui| Breokers, GEI-86134
1.
2.
3.
BREAKER STUD
HEAT SINK
PRIMARY DISCONNECT
ASSEMBLY
Fi.g. 13. Mounti.ngfor speci.al 2500Afuse
AKRU-50 breaksr
FRONT OF BREAKER
FUSE TANGS EE-W@I'
FUSE IS ROTATED ISOO
TO POSITION TANG
BENEATH BREAKER STUD
POSITIONED ON TOP
PRIMARY DISCONNECT ASSEMBLY (SEE FIG.I3 )
MOUNTS DIRECTLY ON OUTBOARD FUSE TANG
Fig. 14. Plan uiew of AKRU-S1 breahsr showing
25004 fuse tang positi.ons
i os osi)
25OOA. FUSE
CAT. NO.
GFgF25OO AK
TANG BOLT HOLES
IN USE
13

GEI-86134, Power Circuit Breqkers
TYPE SST OVERCURRENT TRIP DEVICE
The SST is a solid-state, direct-acting, self-
powered trip device system. Referring to the block
diagram of Fig. 16 and the photograph of Fig. 15,
it comprises the following individual components:
Programmer Unit - provides the comparison
bas-is-T6T-6T6?6frrGnt detection and delivers the
energ'y necessary to trip the breaker. Contains the
electronic circuitry for the various trip elements.
Their associated pickup and timedelay adjustments
(set-points) are located on the lace plate. Depend-
ing on the application, programmer units may be
equipped rvith various combinations of Long Time,
Short Time, Instantaneous and Ground Fault trip
elements. See Table 4 for available ratings,
settings and trip characteristics.
The SST programmer units can be optionally
equipped with trip indicators (targets). These are
pop-out, mechanically-resettable plungers Iocated
across the top of the programmer's front. Units
with a ground fault element employ three targets:
from left to right, the first is for overload, the
second for short circuit (actuated by the short time
andinstantaneous elements) andthe third for ground
fault. The latter is omitted on units without qround
fault.
Each target pops out when its associated trip
element operates to trip the breaker. After a trip,
the popped target must be reset by hand. However,
neglecting to reset does not aJfectnormal operation
of any trip element or prevent the breaker from
being reclosed.
Current Sensors - each pole mounts a single
senE5i-66II(ef)-EETch supplies the power and sig-
nal inputs necessa-ry to operate the trip system.
Each sensor has four taps which provide field ad-
justment of the trip device's continuous ampere
rating. See Fig. 18.
The SST Ground Fault trip element operates on
the principle that the instantaneous vaLues of cur-
rent in the three conductors (four on 4-wire svs-
tems) add to zero unless ground current exists.
On SST's equipped with Ground Fault, the ground
trip signal is developed by connecting each phase
sensor in series with a companion primary winding
on a ground differentia-ltransformer mounted in the
programmer unit. Its secondary output is zero so
Iong as there is no ground current.
l4
Fig. 15. SST Programmer unit
-1
r
I
-
I
([$F$ )
Fig. 16. SST Block diagrant

Power Circuit Breokers, GEI-86134
a
1.. :"
,*"ii
rl
I
i
1. Flux shift Trip Device
2. Allen-head Screws
3. Stud Connector
4. Current Sensor
5. Tap Terminal Board
6. Programmer Unit
7. Clamp Bolt
8. Sensor Stud
Fig. 17. AKR-54-30 breaker with SST trip deuice
Application of the Grorurd Fault element on 4-
wire systems with neutral grounded at the trans-
former requires an additional, separately mounted
sensor (Fig. 19) inserted in the neutral conductor;
its secondary is connected to a fourth primary
winding on the ground differential tralsformer.
See Fig. 2?. This "fourth-wire" neutral sensor is
an electrical duplicate of the phase sensor, includ-
ing taps. Therefore, when taps are changed on the
phase sensors, those on the neutral sensor must be
correspondingly positioned.
FIux Shift Trip Device - a low-energy, electro-
m@n receipt of a trip signal
from the programmer unit, trips the breaker by
actuating the trip sha-tt. See Fig. 22.
All components except the neutral sensor are
mounted on the circuitbreaker. The phase sensors
are located on the breaker's back frame. The pro-
grammer unit and the flux shift trip device are
mounted on the breaker's front frame. These com-
ponents are interconnected by wiring harness and
disconnect plugs, as shown on the cabling diagrams
(Figs. 25 and 26).
When used, the neutral sensor is separately
mounted in the bus or cable compartment of the
switchgear. In drawout construction, its output is
automatically corurected to the breaker via second-
ary disconnect blocks. See Fig. 20.
15

GEI-86134, Power Circui| Breokers
300 - 800 A
Fig. 18. SST phase sensor with tnp board
Pickup tolerance is + 97o
Pickup tolerance is + Wo
Fig. 19.
TAB1E 4
SSI IRIP CHARACTIRISTICS
loo - 300 A
SST Neutral sensors
@ Time detay shown at 60@o of long time pickup setting (6L), at lower limit of band.
o
@@ Time delay shown at lower limit of band.
(See pages 28,29 and 30 for applicable time-cunent curves)
Breaker
Type
Frrme
Size
(Amperes)
X. Trip Rating
in Amperes
-Sensor Tap
SSf PROGRAMMER ADJUSTMET|T RANCE (Set Points)
Long Time Short Time
fnstantaneous
Pickuo
@'
(':Tf*)
GROIjND FAULT
z Seneor t
( mp"t" )
\ Trps /
ria<5(-t )
(':ff") Time
Delav
Band @
(Seconds)
Pickup
o.
(*:'l'i")
Time
Delav
Band-@
(Seconds)
Pickuo
1t\ -
g,/
/ Multipte\
\ of X /
Time
Delav
Band-@
(Seconds)
AKR.30 800 100, 150,225, 300
-or-
300,400,600, 800
.6,.7, .8,
.9, 1.0,
1.1(X)
Maximum
22
Intermed.
10
Minimum
4
3,4,6,
6, 81 10 (L)
---or-
L.75,2,
2.25,2.5,
3,4 (L)
Maximum
0.35
Inrcrmed.
0.21
Minimum
0.095
4,5,6,
8, 10, 12 (L)
,4, .5,.6,
.8, 1.0,
1.2 (X)
AKR.5O 1600 300,400, 600,800
-or-
600,800, 1200, 1600
.25,.3,.4,
.5, .6,
.7 (X)
0.30
Intermed.
0.165
Minimum
0.065
AKRT.SO 2000 800, 1200,
1600,2000 .2,.25,.3,
.4, .5,
.6 (X)
16

Power Circui| Breakers, GEI-J6134
BREAKEFI.
MOUNTED
Fig. 20. Neutral sensor secondary disconnect
blocks
IROUBTESHOOTING
When malfunctioning is suspected, the first step
in troubleshooting is to examine the circuit breaker
and its power system for abnormal conditions such
AS:
a) Breaker tripping in proper response to over-
currents or incipient ground faults.
Breaker remaining in a trip-free state due to
mechanical interference along its trip sha-ft.
Inadvertent shunt trip activations.
WARNING: DO NOT CHANGE TAPS ON
THE CURRENT SENSOES Oft ADJUST
THE PROGRAMMER UNIT SET KNOBS
WHILE THE BREAKER 15 CARRYING
CURRENT.
Once it has been established that the circuit
breaker can beopenedand closednormally from the
test position, attention can be directed to the trip
device proper. Testing is performed by either of
two methods:
1. Conduct high-current, single-phase tests on
the breaker using a high current-low voltage test
set.
NOTE: For these single-phase tests, spe-
cinl cormections mustbe employedfor SST
breakers equippedwith Ground Fault. Any
single -phase i;nfut to the ground differential
transformer will generate cn zmwanted
"ground fault't output signal which utill trip
the breaker. This can be nullified either
by
(a) testing two poles of the breaker in
series, or
(b) Using the Ground Fault Defeat Cable
as sho?,m in Fig. 28. This special
test cable energizes all the pri.mary
windings of the differential trans -
former in a self-cancelling, series-
parallel connection so that i.ts second-
ary output is always zero.
2. Test the components of the SST system using
portable Test Set Type TAK-TSI (Fig. 21). The
applicable test procedures a-re detailed in Instruc-
tion Book GEK-64454 and are summarized on the
next page.
b)
c)
REAR VIEW -
AKR -50
EQUIPMENT.
MOUNTED
t7

GEI-86134, Power Circuit Breokers
Fig. 21, SST/ECS test set, cat. no. TAK-TSI
USING THE SST TEST sET
The TAK-TSI Test Set is a portable instrument
designed for field-checking the time-current char-
acteristics and pickup calibration of the SST's
various trip elements. It can verify the ability of
the Flux-Shift Trip Device to trip the breaker andr
in addition, includes means for continuity checking
the phase sensors.
WARNING: BEFORE CONNECTING THE
TEST SET TO THE BREAKER TRIP DE-
VICE SYSTEM, ENSURE THAT THE
CIRCUIT BREAKER 15 COMPLETELY
DISCONNECTED FROM ITS POWER
SOURCE. ON DRAWOUT EQUIPMENT,
RACK THE BREAKER TO ITS DISCON-
NECTED POSITION. VERIFY I:HAT THE
BREAKER IS TRIPPED.
Either of two test modes may be employed:
rrArt - Programmer Unit Only. These tests are
conduct@ unit disconnected
from the breaker. During test, the unit can remain
attached to the breaker or may be completely re-
moved from it.
18
CAUTION: NEVER DISENGAGE THE
T//,RNESS CONNECTOR FROM THE PRO-
GRAMMER UNIT ON A BREAKER THAT
/S ENERGIZED AND CARRYING LOAD
CURRENT. THIS WILL OPEN-CIRCUIT
THE CURRENT S.ANSORS, ALLOWING
DANGEROUS AND DAMAGING VOLT-
AGES TO DEVELOP.
Test scope:
1. Verify the time-current characteristics and
pickup calibration of the various trip elements.
2. Verify operation of the SST target indicators
on programmer units so equipped.
rrBrt - Complete Trip Device System. For these
tests, mounted on
the breaker and connected to its wirins harness.
Test scope:
1. A11 "A" tests previously described, plus pro-
vision for optionally switching the programmer's
output to activate the Flux-Shift Trip Device and
veri-fy its operation by physicaliy tripping the
breaker.
2. Check phase sensor continuity.
In the event that any component of the SST system
does not perform within the limits prescribed in
test instructions GEK-64454. it should be replaced.

Power Circuit Breakers, GEI'86134
FALSE TRIPPING - BREAKERS EQUIPPED WITH
GROUND FAULI
When nuisance tripping occurs on breakers
equipped with the Ground Fault trip element, a
p"onalte cause is the existence of a false "ground"
slgnaf . As indicated by the cabling diagram of Fig.
26, each phase sensor is connected in series with a
primary winding on the Ground Fault differential
lransformer. Under no-fault conditions on 3-wire
Ioad circuits, the currents in these three windings
add to zero and no ground signal is developed.
This current sum will be zero only i-t all three
sensors have the same electricaL characteristics.
If one sensor di-ffers from the others (i. e., differ-
ent rating or wrong tap setting), the dilferential
transformer can produce output sufficient to trip the
breaker. Similarly, discontinuity between any
sensor and the programmer unit can cause a false
trip signal.
If nuisanc e tripping is encountered on any breal<er
whose SST components have previously demonstrated
satisfactory performance via the TAK-TS1 Test
Set, the sensors and their connections should be
closely scrutinized. After disconnecting the
breaker from all power sources,
a) Check that all phase sensors are the same
type (ampere range).
b) Ensure that the tap settings on all 3-phase
sensors are identical.
c) Verify that the harness connections to the
sensors meet the polarity constraints indi-
cated by the cabling diagram, i.e., white
wire to COMMON, black wire to TAP.
d) On Ground Fault breakers serving 4-wire
loads, check that the neutral sensor is prop-
erly connected (see cabling diagramFig. 2?).
In particular,
(1) Verify that the neutral sensor has the
same rating and tap setting as the phase
sensors.
(2) Check continuity between tlle neutral
sensor ald its equipment-mounted se-
condary disconnect block. Also check
for continuity from the breaker-mounted
neutral secondary discormect block
through to the female harness connector
(terminals L and N).
If the breal<er's lower studs connect to
the supply source, then the neutral sen-
sor must have its LOAD end connected
to the source.
Ensure that the neutral eonductor is
carrying only that neutral current asso-
ciated with the breaker's load current
(neutral not shared with other loads).
e) If the precedingstepsfail toidenti-ty the prob-
Iem, then the sensor resistances should be
measured. Since the phase and neutral sen-
sors are electrically identical, their tap-to-
tap resistances should closely agree.
REPTACEMENT OF CURRENT SENSORS
Referring to Fig. 17, remova! of individuat SST
current sensors is accomplished as follows:
a) Disconnect the breaker harness from the tap
terminal board (5), removing cable ties as
necessary. Unfastenthe terminal board from
the breaker base.
b) At the rear of the breaker, remove the two
Allen head screws (2) to separate the stud
connector (3) from the contact pivot block.
c) Loosen the clamping bolt (7) and remove the
stud connector. Lift out the sensor and its
tap terminal board.
NOTE: To prouide more working clearance
to adjacentaccessories, i,t may sometimes
be necessary to remoae the sensor stud
(8) also. Do this by remouing its foar
holdi,ng bolts, accessible from the rear of
the breaker (see Fig. 20).
(3)
(4)
19

GEI-86134, Power Circuit Breqkers
I BREAKER \
\ CLOSED POSITION /
ACTUATOR
Fig. 22. Flux shi.ft trip deuice and operating
li.nkages
FLUX SHIFT TRIP DEVICE
The mounting arrangement of this component is
illustrated in Figs. 22 and23. An electromagnetic
actuator located on the undersideof the front frame
is coupled to the breaker's trip shaft via a trip rod
driven by the actuator arm. The acfuator is a
solenoid whose armature is spring-loaded and held
in its normal (Reset) position by a permanent mag-
net. In this state the spring is compressed.
So long as the acfuator remains inthe Reset po-
sition, the breaker can be closed and opened norm-
ally at will. However, when a closed breaker re-
ceives a bip signal from the programmer unit, the
actuator is energized and its solenoid flux opposes
the magnet, allowing the spring to release the arm-
ature; this drives the trip rod against the trip shaft
paddle, tripping the breaker.
As the breaker opens, the actuator arm is re-
turned to its normal (Reset) position via linkage
driven by a crank on thebreaker's main sha-ft. The
permanent magnet again holds the armature captive
in readiness for the next trip signal.
The trip device requires only one adjustment -
thetrip rod length. As shown in Fig. 24, the clear-
ance between the trip rod end and the trip shaft
paddle is gaged by a 0.125 inch diameter rod. Ad-
20
just gap to 0. 125 inch+ 0. 015 inch. To adjust, open
the breaker and restore the breaker mechanism to
its Reset position. Loosen the jam nut, rotate the
adjuster end until the proper gap is attained, then
retighten the jam nut.
The actuator is a sealed, factory-set device and
requires no maintenance or field adjustment. In
case of malfunction, the complete actuator unit
should be replaced. When making the electrical
connection to the replacement unit, it is recom-
mended that the breaker harness be cut at some
convenient point and the new actuator leads solder-
spliced thereto. An afternate methodis to untie the
breaker harness and remove the old actuator leads
directly from the female AMP connector on the end
of the breaker harness. However. AMP extraction
tool Cat. No. 305183 is required for this method.
CAUTION: IN THE EVENT TIIAT THE
SST TRIP DEVICE MUST BE RENDERED
INOPERATIVE TO ALLOW THE
BREAKER TO CARRY CURNENT WITH-
OUT BENEFIT OF OVERCURRENT PRO-
TECTION, THE RECOMMENDED
METHOD /S TO SHORTEN THE TRIP
ROD BY TURNING ITS ADJUSTEN END
FULLY CLOCKWISE. THIS PREVENTS
ACTUATION OF THE TRIP SHAFT
PADDLE,