Allis-Chalmers LA-1600 User manual

A CONTROLS
ALUS-CHALMIRS
'INSTRUCTIONS
AIR CIRCUIT BREAKER
•
TYPE LA-1600 & LA-1600F (FUSED)
,
! ---------
,
8WX-6638-6
1SX4582

INDEX-----------------------------------------------------------
INSTALLATION AND INSPECTION. . . . . . .. I
Introduction .......................... I
Receiving and Inspection for Damage
.......... I
Installation . . . . . . . . . . . . . . . . . . . . . . . .
.. I
Storage .............................. I
Maintenance
.......................... 3
OPERATION 3
Description. . . . . . . . . . • • . . • . . . . . . . . . . . .. 3
Manually·Operated Breaker .............. 3
Electrically·Operated Breaker. . . . . . . . . . . .
.. 4
Racking Mechanism, Drawout Interlock, and
Lifting Bar . . . . . . . . . . . . . . . . . . . . . . . .
.. 6
Spring Discharge Mechanism . . . . . . . . . . . . .. 7
Description and Function
................ 7
Adjustments
........................ 7
MAINTENANCE AND ADJUSTMENTS. . . . .. 9
Maintenance
Lubrication 9
9
Maintenance Closing . . . . . . . . . . . . . . . . . . . . . 9
Adjustments
......................... II
Trip·Latch Engagement ................ , II
Main Contact Make ................... II
Arcing Contact Make ................. II
Electrically-Operated Breakers ........... II
Contact Replacement ................... II
Main Contact Fingers ....•••..... _. . .. 12
Stationary Arcing Contact . . . . • . . . • . . .. 12
HInge Contact Fingers ................. 12
Moving Arcing and Main Contact. . . . . . . . .
•. 13
Release Magnet. • . . . . . . . . . . . . . . . . . . . . . .. 13
FUSE FUNCTIONS
...................
14
Current Limiting Fuse ................... 14
Trigger Fuse
......................... 14
CURRENT TRANSFORMERS 16
t_ ILLUSTRATIONS ---------------------------------------
( .'
Figure I
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
-Typical LA-1600 Breaker Outline
..... 2
-Typical Operating Mechanism -
Manually Operated Breaker ....... 3
-TypicalOperatingMec:hanlsm -
Electrically Operated Breaker. . . . .
.. 5
-Typical Wiring Diagram -Electrically
Operated Breakers
............. 5
-Typical Racking Mechanism and
Drawout Interlock
.•........... 6
-Spring Discharge Mechanism
......... 8
-Maintenance Closing. . . . . . . . . . . . . . . 10
•
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure IS
Figure 16
Figure 17
-Typical Panel Assembly. . . . . . . . . . . . . 12
-Typical Release Magnet. . . . . . . • . . . . . 14
-Current
limiting and Trigger Fuse ..... IS
-TypicalBreaker RatingPlate
.......•. 16
-Typical Secondary Disconnects
..•...• 17
-Typical Auxiliary Switch
........... 18
-Typical
Shunt Trip ..............• 19
-Typical Undervoltage Device
......... 20
-Typical BeU Alarm (Manual Reset) . : ... 21
-Typical BeU Alarm(Electricai Reset) ... 22
TABLES--------------------------------------------------------
Table I -Operating Procedure -ManuaUy-
Operated Breakers
............. 4
Table 2 -OperatingProcedure -ElectricaUy·
Operated Breakers ............. 4
Table 3
Table 4
-Maintenance Closing. . . . . . . • . . • . . • •
11
-Trip Rating Table -Amperes ....... 16
The informalion oo"",ned with,n i. intended to us.1t Oper.tlng peoonnel bV prOyidlng informatIOn on the gene'lIl characr",SI'cs 01 equIpment of thIS type. 11 do" IlQI ......... the u_
of responsibllitv to use sound qinetlf'll1I practice. In the i"$tell.l.on, .pplication, op'ration end ..... ;..,1 .... 0<.:11 01 In. parlOcutar t'qu'pmem pUr<;hased.
II dr_,,.. or other SYpplementarv 'nstructions fOf Speo!;"'C appllcatlonl are forwarded w'th Ill,s Il'lIInual or separately. they lake pre<:edence over any conflicllngor mCX)mplet. ,nformallon
,n Illis ... nual.
PRINTED IN U.S.A. SGM & Co •• Inc.

WARRANTY
Allis-Chalmers "LA" air circuit breakers are warranted to
be free of defects in material and workmanship for a
period
of one year after delivery to the original purchaser.
This warranty
is limited to the furnishing of any part which
to our satisfaction has been proven defective.
A11i.s-
Chalmers will not in any case assume responsibility for
allied equipment
of any kind.
Typical ShippingMethods Used With "LA" Breakers
ii
. .

INSTALLATION AND INSPECTION
Introduction
The type "LA" air circuit breakers may be furnished for
mounting in anyone of three ways. They may be used in
metal-enclosed switchgear of the drawout type, in indio
vidual enclosures (pullout type), or for stationary mounting
in a customer's own enclosing case or switchboard. All
"LA" breakers are completely assembled, tested, and
calibrated at the factory
in a vertical position and must be
so installed to operate properly. Customer's primary con·
nections should be adequately braced against the effects
of short circuit currents to prevent overstressing the
breaker terminals.
Receiving and Inspaction for Damage
Immediately upon receipt of this equipment, carefully
remove all packing traces and examine parts, checking
them against the packing list and noting any
damages
incurred in transit. ·If such is disclosed, a damage claim
should be filed at once by the customer with the trans-
portation company and Allis-Chalmers notified.
Two shipping methods are used with "LA" breakers:
I. Individually with protective covering.
2. Within a cubicle when part of a switchgear lineup.
Breakers shipped in their cubicles are blocked to prevent
accidental tripping during shipment. Note all caution
tags, remove blocking bolts, and open breaker contacts
before installation.
Installation
The "LA" air circuit breaker is completely adjusted, tested,
and inspected before shipment, but a careful check should
be made to be certain that shipment or storage has not reo
suIted in damage or change of adjustment. Circuit breakers
should be installed in a clean, dry, well-ventilated area
in
which the atmosphere is free from destructive acid or alkali
fumes (see Figure 1 for dimensional data). Stationary·type
breakers should be mounted high enough to prevent injury
to personneleither from circuit interruption or from moving
parts during automatic opening of the breaker. Allow suf-
ficient space to permit access for cleaning and inspection
and adequate clearance to insulating barrier
above the
breaker to prevent damage from
arcing during interruption.
Before installing, make certain that the breaker contacts
are in the open position.
I. Mter the breaker
is installed in position, close it
manually by the maintenance closing method (see
MAINTENANCE AND ADJUSTMENTS, page 9) to
check proper functioning
of the mechanism and con·
tacts.
CAUTION
Make sure circuit is not energized.
During the closing operation, observe that the contacts
move freely without interference or rubbing between
movable arcing contacts and parts of the arc chutes.
Then refer to OPERATION,
page 3 for a detailed des-
cription of the circuit breaker operating characteristics
before putting the breaker
in service.
2. Trip units and accessory devices should receive a
thorough check prior to placing the breaker in
service
to be certain that adjustments are proper and parts are
not damaged. Refer to Static Trip Device Instruction
Book (l8X4392).
3. Cubicle·mounted breakers
of the drawout type are
equipped with a drawout interlock to prevent movement
of a closed breaker into or out of the connected posi·
tion. See OPERATION, page 3 for a description of the
interlock. Its operation should be checked before the
breaker
is energized.
4. Upon completion
of the installation inspection, the
breaker
is ready to be energized after the control
wiring, if any,
is checked and the insulation tested.
Storage
When breakers are not to be put into immediate use, they
should
be wrapped or covered with a non-absorbent mate·
CAUTIONS TO BE OBSERVED IN THE INSTALLATION
AND OPERATION OF "LA" CIRCUIT BREAKERS
1. Read Instruction Book before installing or makingany changes or adjustments on the breaker.
2. As the closing springs on stored-energy breakersmay be charged in either the breaker open or closedposition,
extreme care shouldbe taken
to discharge the springs before working on the breaker.
3. When closing manually·operated breakers, always grasp closing handle firmly until it is returned to the normal
vertical position.
4. Check current ratings against single line diagram to assure that breakers are properly located in switchgear
at installation.
5. C~eck .the all~nment of the secondary disconnect fingers to ensure against misalignment due to possible
distortion
of fmgers during shipmentand handling.
6. Once the breaker is energjzed, it should not be touched, except for operating, since most of the component
partsare also energized

to
72_440_007-401
;-REAR PAN
~~RIP
l&~\ S~AFT
DETAI L "A"
(LEFT SIDE VIEW)
COVE~
(~FRAME
DETAIL"B"
(TOPVIEWl
BARRIER{ 104
FRAME
DETAIL lie II
( LEFT SIDE VIEW)
RELEASE
MAGNET
'.0
-.062
21.625
1.
",.,
6.
250
1
I '.06'1
~l.B12 I
I
~: J , ... ~ It'
.-, Jl I .1 .i1?2 f - r<
!.062
20.719
STRAP RAIL RADIUSG) SEE TABLE 4
I /' t
I03)SARRIER BELL ALARM ~ 116 ~ ~ ARC CHUTE
RACKING (ATTACHMENT) 115 ~ _ 14 6-5~6~~ ! 062
1 8 CURRENT
SCREW (SEE DETAIL-B) . r--6.437~ I TRANSFORMERS
UNOERVQLTAGE 127 INTERLOCK • 1.681 4.0 IO~.QiII1 4.~ga2M./' /' 2.250
DEVICE nLJ==L,LI;--:;:r SLIDE COVER - - . • --~~-'--11 -.-- /' - ~- f.
(ATTACHMENT) .062 a' /, 500 !062 .. PRIMARY
440& RACKING CRANK~ ; ._, 1375 ____ DISCONNECTS
--,
(ATTACHMENT) - 500 LATCH f.......... ! I
%062 -........ '1 --- ..
FREE POSITION .625 _ ~ ON ELECTRICALLY -- 5.625 18 250
OPER. BREAKERS I
NORMAL OPER. POSITION .187, . :;. ': ~' MANUAL HANDLE ! 062 .~ !.031
SECONDARY L ~ • :.~ ~ IS NOT INCLUDED' 16'~ .,....... 9.500
DISCONNECTS 106:!" OEli! .625R ." I ON THE BREAKER. 1"'------ FREE POSIT. I1I.S63
.500~ ',b::cr 'Q .375 MARKINGS ON'" \. • -- 5.125 t I
SECONDARY~ ~ OPPOSITE LV ............._
DISCONNECTS\!,~ ti·
812 SIDE
APPAOX'I .. L...LL5-b&:!i ~
V RAIL
!062 9.687.......... ~I . 120 122 WASHER
"y". RELAY a 20.500 .187 :t062
SHUNT TRIP 108 ~ 0v ~ VERT. TRAVEL: 2.250 BIER
(ATTACHMENT) TRIP ELECTRICAL TO TRIP ,.37 8 123 GROUND
(SEE OETAIL:A") ROD 110 SPRING 125 BAR
CONTROL SWITCH III STATIC e.c· RELEASE CUBICLE --.--J 124 INTERLOCK
(ELECTRICALLY
OPER. 109 TRIP DEVICE (ATTACHMENT) INTERLOCK
BREAKERS) (SEE
DETAIL-MC'" CAM
Figure 1. -TypiClli LA-l600 Breaker Outline

rial to provide protection from plaster, concrete dust, or
other foreign matter. Breakers should not be exposed to
the action of corrosive
gases or moisture. In areas of high
humidity or temperature fluctuations, space heaters or
the
equivalent should be provided.
Maintenance
Occasional checking and cleaning of the breaker will pro-
mote long and trouble·
free service. A periodic inspection
and servicing at least every six months should be included
in the breaker maintenance routine.
If the circuit breaker is not operated during extended
periods, the breaker should not remain
in either the
closed or open position any longer than
six months.
Maintenance opening and closing operations should
be
made to ensure freedom of movement of all parts.
OPERATION
Description
The LA·1600air circuit breaker has an interrupting capacity
of 42,000 amperes and a maximum continuous current
rating of 1600 amperes at 600 volts, 60 cycles. For infor·
mation on other voltages or frequencies, the factory should
be consulted.
It is available as a manually-operated breaker
or an electrically·operated breaker. The two breakers
are
identical withthe exception of the medium used to transmit
power to charge the stored-energy springs.
A double.toggle, trip-free mechanism
is used; that is, the
breaker contacts
are free to open at any time, if required,
72-340-014-401
SPRING
SPRING
RACKING
SCREW
regardless of·the position of the mechanism or the force
being applied.
MonuaUy-Operated Breaker
As the breaker has a single-frame type construction, most
of the latches and linkages are arranged in pairs; however,
for descriptive purposes, they will be referred to as single
items. Refer to Figure 2 and Table I. Detail "A" shows
the position of trip latch (216) when the breaker contacts
are open with the closing spring discharged. Movement of
closing handle (201) downward rotates
cam (208) against
roller (205), thus pivoting closing cam (210) clockwise
TOGGLE
LINKAGE
STOP
TRIP SHAFT
TOGGLE LINKAGE
DETAIL-MAil
DETAIL-"e"
DETAIL-lie"
DETAIL-"OII
Figure 2. -Typical Operating Mechanism - ManUlllly Operated Breaker
3

about pin (206) and extending stored-energy springs (209)
through link (225) and pin (226)_ Rotation of cam (210)
clockwise permits spring (217) to collapse toggle linkage
(213) and (220)_ At the same time, trip latch (216) is
reset by torsion spring (228) as shown in Detail "B"_ Push-
ing down spring release latch hood (202A), after the closing
handle
is returned to the normal vertical position, releases
the energy in springs (209)_ Through link (225), closing
cam
(210) is rotated counterclockwise against roller (219),
which moves toggle linkage
as shown in Detail "C", to
close the breaker contacts. The closing operation may
be
interrupted at any point by functioning of the trip device,
thus ensuring "trip_free" operation.
TABLE 1. OPERATING PROCEDURE-
MANUALL V-OPERATED BREAKERS
Operation Procedure
Charging Springs Pull handle (201) down all the
way (approximately
120~ and
return to normal vertical posi-
tion. (Engagement
of pawl (211)
with the ratchet teeth prevents
handle reversal until the down-
ward stroke is completed.)
Oosing Push down spring-release latch
hood (202A) after handle
is
returned to normal vertical posi-
tion.
Tripping Push in manual trip rod (207).
or
If shunt trip is provided, operate
remote trip control switch (CST)
(See Figure 4.)
To open the breaker contacts, trip rod (207) is actuated.
This rotates trip shaft (215) clockwise which releases trip
latch (216)
as shown in Detail "A". On breakers equipped
with a shunt trip device, the breaker contacts may
be
opened by operation of a remote trip control switch. The
shunt trip device rotates the
trip'shaft to release the trip
latch.
Electrically-Operated Broeker
The mechanism
of the electrically-operated breaker is the
same
as that of the manually-operated breaker except that
the manual closing handle
is replaced by an electric motor
and the gear system.
Refer to Figures 3 and 4 and Table
2. Movement of the
control switch (N) located on the front of the breaker to
the "ON" position, when the (';ontrol circuit is energized,
will start the automatic closing cycle. Motor gear box
pinion (338) rotates gear (335) counterclockwise, and
pins (336) move across the top
of !lat biasing spring (334).
This raises gear (335) to mesh with gear segment (340).
4
Since this gear segment is attached to closing cam (310),
the stored-energy springs are charged and latched in the
same sequence as described in the previous section_
As gear (335) reaches the last tooth on segment it is dis-
engaged by means of spring (348)_
Spring-position switch (330) (SPS b) is actuated to the
open position by arm (331) attached to link (325)
as the
stored-energy springs approach the charged position. This
switch initiates the spring recharging cycle and is connected
in parallel with motor cut-off switch (332)
(88 a) which
is open initially, closes while the motor charges the springs,
and opens when the springs are charged with the gearing
disengaged. The motor cutoff switch is actuated
by the
movement
of plunger (333) over pins (336). Approximately
·twelve seconds are required for completion of the spring
charging cycle.
The breaker may now be closed
by pushing down spring-
release latch hood (302A) as in the manually-operated
breaker, or it may be closed electrically through remote
close control switch (CSC). This switch energizes spring-
release coil (SRC) which moves pin (341) in a counter-
clockwise direction to trip spring release latch hood (302A)
and spring-release latch (302). The "Y" call is energized
simultaneously with the spring-release coil and causes
the "Y" contact to open the circuit to the motor_ Since
the "Y" relay will remain energized as long
as the remote
close control switch (CSC)
is held closed, "YI" contact
keeps the motor circuit open to prevent "pumping" or
repeated attempts to charge the stored-energy springs
when the breaker
is closing.
After the stored-energy springs are discharged, they are
automatically recharged as long as the control circuit is
energized, and the
motor toggle switch (N) is in the "ON"
position. Figure 4 shows the spring-position switch (SPS b)
closed to complete the motor control circuit
as it would
be when the springs are discharged.
TABLE 2. OPERATING PROCEDURE -
ELECTRICALLV-OPERATED BREAKERS
Operation Procedure
Charging Springs Energize control circuit.
Move
control switch (N) on front of
breaker to
"ON" position.
Closing After springs are charged, actuate
remote close control switch
(CSC). or
Push down spring-release latch
hood (302A).
Tripping Actuate remote trip control
switch (CST). or
Push in manual trip rod (307).

,
/
• ARM ............
• LINK
• PIN .............
eTRIPROD
.SPRING
(X)I+)
SPRING
POSITION
SWITCH
,-i1 ..... LJ-\ 331 REF
~.~--i-------- SWITCH ".9).. __ .'
: ~~ BRACKET \.
CLOSING
CAM
MOTOR
Cur·OFF
SWITCH
NUT
~~~NUT
FLAT SPRING GEAR PINS MOTOR GEAR-BOX
PINION
PLUNGER
EYE
END
Figure 3. -Typical OperatingMechllnism -Electrically Operated Breaker
REF
NOTE: SWITCHES
MOUNTED ON
BRACKET
-- ----------- ----- - - -- -- -r-"
-I·~---r;-------I~s-c----~ t~~
(X)(+) _______________________ ~ __ ,
ee SPS 'Y t--'>"
I G I R
o b 'T2
~ S~ As
SUPPLY M Y, e": Y 1 ,T
- f' \IIJ>- -Ti------Tcs.;---- -~' *CS-T®:
nee ,x-
2
--
~PPLY:, 's T
- .~~+
IY)(-) --7'
4 ~
, ,
st'
61
v :s
9 10
N S b r
3 b
•
AC CONTROL
;,,;':'9:f fir r
4
,
~1
sf
v ~
9 10
DC CONTROL
DVERCURRENT STATIC TRI P DEVICE WIRING
TRANSFORMERS xt 'X2 Ixl2~211 "i'l>;ll
MAGNETIC
TRIP
COIL
o
2
2. 3
o 0 o 0 0 0 STATtC TRIP
3 4 5 6 7 B
TERMINAL BLOCK
Figure 4. -Typical Wiring Diagram -Electrically Operated Breakers
5

Racking Mechanism, Drawout Interlock, and Lifting
Bar.
Cubicle-mounted breakers of the drawout type include as
integral parts the mechanism to rack the breaker in and
out
of the cubicle compartment, the drawout trip inter-
lock, and the drawout position markings_
72-440-010...01
RACKING
CLEVIS
DETAIL-IIA'•
RACKING
SCREW
RACKING
CLEVIS
,
TRIP ROD
(ELECTRICALLY
OI'£R. BREAKERS)
CUBICLE
FIXED PIN
TRIP SHAFT
Refer to Figure 5_ Lifting bar (SOl) may be used to lift
the breaker when
it is being inserted in the cubicle_
With the breaker in position on the rails, the following
sequence should be used to rack the breaker into the fully
connected position.
LIFTING BAR
INTERLOCK SLIDE
---,
I.'
.""'e
•• CUBICLE
INTERLOCK INTERLOCK CAM
SIDE VIEW
Figure 5. -Typical Racking Mechanism and Drawout Interlock
6

CAUTION
On electrically-operated breakers, be cenain that the
control switch on the front
of the breaker is in the
"OFF" position.
I. Push trip bar and lower the interlock slide (502) to expose
racking screw (504). (Lowering the interlock slide will
also actuate trip rod
(506) SO that a closed breaker will
be tripped.) While the interlock slide
is in this position,
the breaker is "trip·free" and cannot be closed.
2. With the switchgear operating crank, rotate racking
screw
(504) to move racking clevises (505) to the posi·
tion shown where they will engage with fixed pins (503)
in the cubicle.
3. The breaker should now be pushed along the rails to
the "DISCONNECTED" position. At the same time
the racking clevises (505) should be checked
to see that
they are in correct alignment with cubicle fixed pins
(503).
Counterclockwise rotation of the operating crank will
now rack the breakerintothe "TEST" and CONNECTED
·positions.
At the ''TEST'' and CONNECTED positions,
interlock
(508) is in its normal horizontal position. By
removing operating crank and then raising interlock
slide (502), trip rod (506) returns
to the extended posi·
tion permitting trip shaft (507) to reset and the breaker
may be operated.
Between
''TEST'' and CONNECTED positiQns, the cubicle
interlock cam
(509) raises interlock (508) to hold trip
rod
(506) and trip shaft (507) in the "trip·free" position
so that
the breaker cannot be closed even if interlock
slide
(502) is raised. This is to prevent movement of a
closed breaker into or
out of the CONNECTED position.
4.
To withdraw the breaker from the CONNECTED position,
the procedure
is the same except that the direction of
rotation of the operating crank is clockwise.
5.
If necessary to adjust racking screw stop (510) rotate
racking screw (504) until racking clevis (505) reaches
the
77
0 position
as shown' (Detail "A"). Position
stop (510) against crank (511) with nut (512).
CAUTION
To avoid damage to the racking mechanism, do
not rotate the operating crank in the counterclockwise
direction after the breaker has reached the fully
connected position.
Spring Discharge Mechanism
Description and Fu netion
(See Figures 2 and 6.) When racking circuit breaker OUT
of cubicle (see Racking Mechanism, Drawout Interlock.
7
and Lifting Bar, page 6) the stored energy closing
springs
(209) will automatically discharge prior to or when
circuit breaker reaches the DISCONNECT position.
This
is accomplished by the following sequence:
1. Lever (601) rotates clockwise during RACKOUT,
allowing roller (602) on lever (601) to rotate
carn (603) counterclockwise.
2. Cam (603) moves rod
(604) upward which in turn
rotates lever
(605) clockwise.
3. Lever (605) in
turn rotates spring release latch (613)
clockWise allowing the storedenergy closing springs (209)
to discharge.
4. When roller (602) strikes carn (603) and stored energy
springs discharge, cam (603) must snap back into reset
position prior to or when circuit breaker reaches the
DISCONNECT position.
Adjultmentl
If adjustment becomes necessary the following procedure
will be required (see Figures
I, 2, and 6):
1. Remove cover (126).
CAUTION
With cover removed and circuit breaker contacts
open, the circuitbreaker will CLOSE when the stored
energy springs are discharged automatically since the
slide interlock is not inplace.
2. Align scribed line on trunion (606) with center punch
mark (TEST position)
on arm (607).
3. Remove cotter pin
(610, remove washers (611),
remove rod
(604) from cam (603). Adjust rod I (604),
by screwing into or out of yoke (612) until the nominal
.375 dimension
is obtainedbetween the end of rod (604)
and inside of yoke (612). Insert rod (604) into
cam
(603), replace washers (611), insert cotter
pin (610) and bend.
4. Charge stored energy springs
(209) and rotate racking
screw (222) in the clockwise direction (see Racking
Mechanism, Drawout Interlock, and Lifting Bar, page 6).
The stored energy closing springs should automatically
discharge (see caution note, above) prior
to or when
circuit breaker reaches the DISCONNECT position.
Cam (603) must snap back to reset position as shown.
(See Step 4
of Description and Function, above.)
5. If the stored energy closing springs DO NOT auto-
matically discharge as described in Step 4:
a) Repeat Adjustments, Step 2.
b) Readjust as necessary per Adjustments, Step 3 within
the prescribed tolerance limits
of .375 :!:,.062.
6. Repeat Adjustments, Step 4.

72-240-103-401
SET SC~'EWr.o,i'\
NUT
j
-0- SHAFT ---
(TEST POSITION)
ROLLER
DISCONNECT POSITION
Figure 6. -SpringDischarge Mechanism
8
,
,
~
,
,
~
CAM
(RESET POSITION)
COTTER PIN
WASHER
LEVER
LATCH

<"\
•
-
MAINTENANCE AND ADJUSTMENTS
Maintenance
Occasional checking and cleaning of the breaker will pro-
mote long and trouble-free service. A periodic inspection
and servicing
at intervals of six months or one year should
be included in the maintenance routine. Circuit breakers
located in areas subject
to acid fumes, cement dust, or
other abnormal conditions, require more frequent
ser-
vicing. After a severe overload interruption, the breaker
should be inspected.
If the circuit breaker is not operated during extended
periods, it should not remain
in either the closed or open
position any longer than six months. Maintenance opening
and closing operations should be made to ensure freedom
of movement of all parts.
A suggested procedure
to follow during maintenance
inspections
is given below.
I. De-energize the primary and control circuits.
2. Rack cubicle-mounted breakers of the drawout type to
the disconnected position.
4. Remove breaker from cubicle.
5. Remove arc chutes (117, Figure I) and examine for
burned, cracked
or broken parts. To remove arc chutes,
proceed as follows (see Figure 5):
a.
Move breaker to disconnect position.
b. Turn racking screw (504) until crank (511) IS m
vertical pOsition, giving maximum clearance between
screw and holding bar.
c. Remove wing nuts from holding bar.
d. Tilt top
of holding bar toward back of breaker and
move bar down.
NOTE
After inspection and before moving breaker to test
position,
turn racking screw (504) until racking
clevis (505) reaches its normal disengaged position.
6.
Wipe the contacts with a clean'cloth saturated with a
non-toxic cleaning fluid.
7. Replace badly burned or pitted contacts (see Contact
Replacement, page II).
8. Wipe all insulated parts with a clean cloth saturated
with a non·toxic cleaning fluid.
9. Bearing pins and other sliding or rotating surfaces should
be cleaned and then coated with a light film of grease
(see Lubrication, next paragraph).
10. Operate the breaker manually in maintenance closing
position (see Maintenance Closing, below)
to check
latch and linkage movement.
9
II. Check breaker adjustments (see Adjustments, page 11).
Lubrication
Lubrication should be a part of the servicing procedure.
Needle bearings are packed with
grease and should require
no further attention. Old grease should be removed from
bearing pins and other rotating or sliding surfaces, and
they should be wiped with a thin film
of petroleum-oU·
base precision-equipment grease similar to BEACON P-290.
Greasing should be done with care because excess grease
tends to collect foreign matter which in time may make
operation
sluggish and may affect the dielectric strength
of insulating members. Faces of main and arcing contacts
should not be lubricated. The rubbing surfaces
of the main
contact fmgers and hinge contact fingers
are lubricated
with micro
fme dry graphite. If dust has accumulated, dis-
assembly is necessary to relubrlcate these points (see
Contact Replacement, page II).
Maintenance Closing
During inspection prior to installation and for routine
maintenance inspections, the breaker contacts may be
closed slowly
to check clearances, contact adjustments, and
movement
of links and latches. The manual closing handle
is used for maintenance closing the breaker.
Electrically·operated breakers do not have a manual closing
handle,
but a manual closing handle-carn assembly is
available as a maintenance item. Figure 7 shows the main-
tenance closing handle being inserted in an electrically·
operated breaker after removal
of the front cover from the
breaker.
When the hole in the maintenance closing handle
assembly is aligned with the holes
in the operating mech-
anism frarne, the pin which is attached to the chain is
inserted. This pin holds the assembly in place and acts as a
pivot point for the earn.
After insertion
of the maintenance closing handle assembly
on the electrically.operated breaker, the actual maintenance
closing operation
is the same for both the electricaUy·
operated breaker and the manuaUy-operated breaker. Refer
to Table 3 and Figure 7.
CAUTION
The procedure in Tabl. 3 should b. used for main·
tenance closing only .

MAINTENANCE CLOSING H'ANOLI, -; :- _______ J
(SEE PAGE 9)
RELEASE LATCH HOOD ____ ~- ~
MAINTENANCE CLOSING HANDLE
ELECTRICALLY OPERATED BREAKERS
SEE TABLE 3 a FIG 2 {STEP I
. STEP
TYPICAL MAINTENANCE
CL OSI NG HANDLE PROCEDURE
MA N UAL TRI PR OD
Figure 7. - Maintenance Closi ng
10
.,
~ .•
•
-

-.
TABLE 3. MAINTENANCE CLOSING
Operation Procedure
Closing Contacts
1. Pull closing handle DOWN
ALL THE WAY
(approx·
imately 120~.
2. Place blade of screwdriver be·
tween hood and spring reo
lease latch and hold it in
this position.
3. Slowly return handle to ver·
tical position.
(Contacts will close to arc-
ing contact touch position,
but breaker will not close
completely.)
Opening Contacts Push in manual trip rod.
NOTE
Holding the spring release lateh down prevents the
stored-energy springs from propping in the charged
position. Thus, when the handle
is slowly returned
to the normal vertical position, the energy in the
springs
is slowly released against the closing handle
assembly cam face.
Adjustments
During maintenance inspections, the following items should
be checked to ensure that the original settings are main-
tained:
Trip-Latch Engagement
(Refer to Figure 2.) Trip latch (216) should have an engage-
ment of .062" plus 0 minus .015" on trip shaft (215).
Measurement is made with the latch resting on the shaft in
the reset position. With this engagement, the trip shaft
must rotate between 10.50 and
ISO to release the trip
latch.
Main Contact Make
(Refer to Figure 8.) Compression of contact fingers (817)
should be between
.093" and .125". This is the difference
in the measurement from the breaker base to the
bottom of
the finger contact surface when the breaker is open and the
measurement in the same place when the breaker
is closed.
This is checked with a normal closing operation -not
maintenance closing. Adjustment is provided by positioning
screws (810) after loosening nuts (814). Counterclockwise
rotation
of screws (810) increases compression. Care should
be taken to retighten nuts (814) after adjustment. If it is
desired to check contact pressure, a push-type spring scale
can be used to compress contact fingers (817) with the
11
breaker open. Contact pressure should be between 20 and
30 pounds.
Arcing Contact Make
(Refer to Figure 8.) With movable arcing contact in anyone
phase touching the mating stationary contact when the
breaker
is closed by the maintenance closing method (see
Table 3), the phase-te-phase variations should not exceed
.061 ". Adjustment may be made by positioning screws (810)
as in the preceding paragraph, but it is essential that the
maincontactcompression be maintained within the tolerance
of .093" and .125". Arcing contact pressure can be checked
with the breaker contacts closed by pulling
both contacts at
the base of the arcing contact tip insert with a pull-type
spring scale until contacts part. The contact pressure should
be between 70 and 80 pounds.
Electrically-Operated Breaker.
(Refer to Figures 3 and 4.)
I. Motor-Cut-Off Switch and Spring-Position Switch
These switches are mounted on a common bracket which
is set and roll-pinned in pOsition during production
testing. If replacement is required, the bracket must be
pOSitioned so that when roll pins (336) in gear (335)
are at the top position, they have moved plunger (333)
against the roller
of motor cut-off switch (332) to shut
off the motor. As the springs are charged, arm (331)
must engage the roller
of spring-pOsition switch (330).
Pilot holes are provided in the mounting bracket for
drilling and roll-pinning the replacement assembly in
the correct position.
2. Gear Disengagement
(Refer to Figure 3.) With the breaker closing cams (310)
in the horizontal position, adjust the tension
of
spring (348) by means of eye end (300) and nuts
(301, 304) until a dimension of 2 3/8 !1/32 is
measured between spring loops. This dimension is
measured when gear (335) touches or meshes with gear
segment (340).
At this point a force of 5 1/2 to 7 Ibs
will
be required to hold the gears in contact.
Contact Replacement
(Refer to Figure 8.) The contact structure consists of main
current carrying contacts and arcing contacts arranged
so
thatinitial contact make and final contact break is by means
of the arcing contacts. The main contacts are not subject
to arcing. The actual contact surfaces are clad with an alloy
facing which greatly reduces mechanical wear and arc
erosion.
When inspection of the alloy facing indicates that the con-
tacts should be replaced, it should be noted that hinge con-
tact fingers (820), main contact fingers (817) and arcing

72-340.()'21-401
CONTACT
FINGER
DETAIL-"A"
------
@
@
tKj tKj
0 0 0 0
IP< : >QJ ©¢"'5()
0 0 0 0
I
@
0 0
o 0
0
.187 DlA
CONTACT
ING
(J)
@
~ 0
0
SET SCREW
WRENCH
DETAIL-"a"
BASE
SPRING
CLEVIS
SCREW
WASHER
PAN
SPACER-SEE
DETAIL--A-
I ARC RUNNER
Figure 8. -Typical Panel Assembly
contacts (819) are spring loaded. Therefore, extreme care
must be exercised in removal and installation
of any of the
contacts.
Main Contact Fingers
With the breaker contacts open and the stored-energy
springs discharged, main contact fingers (817) may be
reo
moved by loosening screws (823) enough to relieve the
compression
on springs (822) as shown in Detail "A".
There are two springs behind each fidger, and it is important
that they be positioned properly upon reinstallation.
If
difficulty is experienced in correctly positioning these
springs, the upper and lower primary disconnects (119,
Figure
I) may be removed from each phase and the
breaker inverted to rest on the ends
of connectors (824)
and (828).
After the contact fingers are replaced, connector (824)
should be positioned in the center
of the slot in the molded
base to assure correct alignment
of the primary disconnect
fmgers.
Stationary Arcing Contact
The stationary arcing contact is a part of connector (824)
and may
be replaced by proceeding as above. In this case.
12
screws (823) must be removed. However, to provide a
clearance for removal
of connector (824), first insert a
.187" diameter rod
at least 3" long through the opening
in support (821)
as shown in Detail "B". This will hold
hinge contact fmgers (820) in position to permit removal
of pin (805). It may be necessary to compress contacts (820)
opposite arcing contacts
(8l9) in order to insert the rod.
(As
an aid in holding spacers (804) and (806) in their
correct positions, withdrawal
of pin (805) can be followed
by the insertion
of a shorter pilot pin to permit removal of
the complete movable contact assembly as a group from
support (82l).) The pin at the end of clevis (802) should
then
be removed so that the complete movable contact
assembly can
be positioned or removed to provide clearance
for removal
of connector (824).
Hinge Contact Fingers
Hinge contact fingers (820) may be removed as follows:
Remove top screws
(826) from support (82 I) and replace
them with two .250-20 screws at least
IS' long. Remove
lower screws
(8l6) and then gradually back off the lS'·
screws as shown in Detail "8". to relieve the loading from
springs (827). The hinge contact fingers can now be reo
moved. Be certain to replace the 1.5" long screws with the
original screws after replacement
of the contact fingers.

in position to permit removal of pin (803). After removal of
pin (803). main contact (817) and arcing contact (820) can
be positioned so that connector (829) can be removed.
Hinge Contact Finger.
Hinge contact fingers (814) may be removed as follows:
Remove top screw (827) from support (815) and replace it
with a 1/4·20 screw at least 1·1/2" long. Remove lower
screw (827) and then gradually back
off the 1-1/2" screw
as shown
in Detail "B", to relieve the loading from
springs (828). The hinge contact fingers can now
be
removed. To provide easier access to the hinge contact
fmgers, pin (803) may
be removed after tbe loading is
relieved from springs (828).
Moving Arcing and Main Contact
Either moving arcing contact (820) or main contact (817)
or both may be removed and replaced as follows: Follow
the steps outlined
in the above paragraph including removal
of pin (803) or
if hinge contact fingers are not to be re-
placed, omit these steps and begin by placing a 3/16"
diameter rod at least 2" long through the opening in
support (815) as shown in Detail "B". Remove pin (SOl)
and pin (S03) if these have not been removed previously.
The complete movable contact assembly may now
be
brought to a bench. It is suggested that a I/Z" thick piece
of wood or phenolic be placed upright in a vise and the open
slot in
clevis (812) placed against it as a rest. The. location
of spacers (802), (S04) and (825) should be noted. To
minimize adjustment upon reassembly, the position
of the
two screws (80S) relative to pin (818) should also
be
noted. Then the two elastic stop nuts (S21) should be
loosened and screws (80S) backed off far enough to
remove them from pin(SIS).
CAUTION
Extreme care should be taken to hold the assembly
firmly to retain spring guide (bID) and spring (809)
upon removal of the screws.
The moving arcing contact or the main contact may now be
easily replaced. The reverse procedure is followed for re-
installation. Care should be taken to replace spacers (S02).
(804) and (S25) correctly. Check alignment and adjust-
ment of contacts upon reassembly.
Release Magnet
When the static trip device senses a circuit condition that
requires the circuit breaker to open, it produces an output
that is fed to the magnetic latch release device. This device
then causes the circuit breaker contacts to open and isolate
the circuit.
13
Mounted on the circuit breaker, the magnetic latch release
is held in a charged position by a permanent magnet. It
contains a coil that is energized by the output of the static
trip device.
When energized, the coil causes the magnetic
flux to shift to a
new path, releasing the stored energy ofa
spring located
inside the magnetic latch r~lease. The spring
provides
the energy to trip the breaker.
The
release magnet is illustrated in Figure 9. During normal
operation. trip rod (901), which
is attached to a spring
loaded armature inside the magnetic
release latch cylinder,
cannot move due to a magnetic
field set up by permanent
magnet (902) which holds the internal armature against
plate (903) on the bottom of the magnetic release latch.
When an overload or fault condition exists, coil (904),
which is inside on the bottom of the magnetic release latch.
is energized by the static trip device creating a flux which
decreases the magnetic hold force on the spring loaded
internal armature allowing the armature to
be forced up-
ward due to the spring load, thereby allowing trip rod (901)
to move up against trip arm (905). in turn, tripping the
circuit breaker.
As the breaker opens. coil (904) becomes
de-energized due to de-energization of the static trip
device, cam (906) rotates
arm (907) forcing spring loaded
armature against plate (903) allowing trip rod (901) to
be
reset to the non·trip pOSition.
If the spring loaded armature does not reset during trip
operation
as explained above, spacers (908) may be added
to obtain positive reset of the armature.
If adding spacers does not allow armature to be reset. th,
magnetic release latch should be replaced (if breaker mech-
anism is not at fault).
NOTE
Do not attempt to disassemble the magnetic release
latch as this
will destroy the magnetic field set up by
the permanent magnet and
will render the release
latch inoperative permanently.
When replacing a magnetic release latch, the coil (904)
leads must be connected to the terminal block of the static
trip
in the correct polarity relationship.
The black lead ofcoil (904) must
be connected to terminal 7
(negative) and the red lead of coil (904) connected to
terminal 8 (positive) of the static trip device.
A clearance of .032" to .060"
shOUld be maintained be-
tween the trip arm (905) and nut (909) with the circuit
breaker open, springs charged and trip
arm (905) reset by
the trip shaft. Adjustment is made by positioning nut (909)
while holding trip rod (901).
When the magnetic release latch has been replaced the
circuit breaker should
be given a FUNCTION TEST to
ensure proper operation of all components. Refer to
Allis-Chalmers Instruction Book 18X4392 for the procedures
of the FUNCTION TEST.

72·240-068-401
CAM POSITION ----~
(SREAKER CLOSED)
CAM POSITlON-_~
(BREAKER OPEN)
SPACER
PLATE
TRIP ARM
/
/
/
TRIP ROD
CAUTiON
SEALED UNIT. 00
NOT DISASSEMBLE
NUT
TO .060
'. ----,
RESET CAM
RESET ARM
COIL
Figure 9. -Typical Release Magnet
FUSE FUNCTIONS
Current Limiting Fuse
(See Figure 10.) The C.L fuse (100\) NEMA Class "J" and
Class "L" have an interrupting rating of 200,000 Amps
RMS Symmetrical.
When replacement is required due to the C.L fuse inter·
rupting, replace only with a fuse of the same manufacturer
and rating
as supplied with the circuit breaker. Fuses of
different manufactures may have c~nsiderably different
melting time·current characteristics and peak let·thru cur-
rents and, consequently, may not be completely inter-
changeable.
14
To remove the C.L fuse, remove bolts (1002) and as·
sociated hardware. Remove fuse. To replace the c.L. fuse,
reverse the above procedure.
Trigger Fuse
(See Figure 10.) The trigger fuse (1003) and associated
trip mechanism has a dual function. The first function is to
trip the circuit breaker mechanically when the C.L. fuse
has interrupted.
The second function is to indicate which phase C.L fuse
has interrupted.

71·240·102-401
TRIP ARM
!cL l
FUSE
BOLTS
ARM
TRIGGER
FUSE
~.~.,. LEVER
COVER
r--l~~~~~~:~ FUSE WIRED IN PARALLEL
WITH ASSOCIATED C.L: FUSE.
Figure ZO. - Current Limiting and Trigger Fuse
The plunger (1004) on top of the trigger fuse indicates
visually which phase C.L.
fuse has interrupted.
The trigger fuses are wired in parallel with the C.L. fuse.
When the C.L. fuse interrupts, its associated trigger fuse
also opens and releases a plunger (l004) which is operated
by a precompressed spring contained in the trigger
fuse
housing.
The plunger operates
arm (l005) which allows spring
loaded
lever (1006) toengage circuit breaker trip arm (1007)
•
which trips the circuit breaker and holds the circuit breaker
in the mechanical trip free position.
The circuit breaker will remain trip free (cannot be closed)
until the trigger
fuse has been replaced and the associated
15
trip mechanism reset lever (I ODS) has been manually
reset (pushed in).
To remove the trigger fuse remove strap (l009), remove
plastic cover (1010), then the trigger fuse.
To insert the trigger fuse, reverse the above procedure.
CAUTION
The trigger fuse (T003) must be inserted with the
plunger11004) facing arm (1005). The .125 + 0- .032
dimension must be maintained.

CURRENT TRANSFORMERS
There are a number of tripping tran~former ratings avail-
able, each with seven calibrated pickup settings (Table 4).
Figure
II shows a typical breaker rating plate.
The current transformers on the upper connectors for the
lA·6OQ circuit breaker are mounted with the polarity
marks facing breaker panel. .
Breaker Tripping
Type and XFMR
Frame
Rating
Size
tl A
LA·6oo
80 40
200
100
600
400
200
600
300
The current transformer on the lower connector is mounted
with the polarity mark facing away from the breaker panel.
TABLE 4. TRIP RATING TABLE -AMPERES
Ground Element
Long Time Element
Max
Calibrated Pick.Up
Calibrated Pick·Up Settings Cont
2~~~ B C D E F G
50 60
70
80
90
100 100
.
32
64
80
125 150 175
200 225
250 250
40
80
160
200
250
300
350
400
450 500 500
80
160
320
400
375
450
525
600
675 750
600 120
240
480
600
SERIAL 10.
Figure 11. - Typical Breaker RatingPillte
16

71·240-584-401
BRACKET 1203 1207 BRACKET 1204 SHIELD
~t:I~1 NG 1205
::-: - ~~~CONTACT 1201
I
-t-- -, _BLOCk
, 'I
i+
n
•• I i.~,
,'
IO-DISCONNECT MOUNTING
lO-DISCONNECT MOUNTING
TERMINAL I
TERMINAL TAB
Figure 12. - Typical Secondary Disconnects
The electrical attachments are wired to the terminals of a
secondary disconnect assembly which
is mounted on the
left
side of the breaker_ Two blocks of ten terminals each
can be mounted on the breaker. The secondary disconnect
17
assembly is accessible from the front of the breaker and
aligns with a stationary unit in the cubicle. The stationary
contact strips should
be lucricated with a light film of
AERO LUBRIPLATE which is furnished with the switch·
gear.