> INSTRUCTIONS AND RECOMMENDED PARTS FOR MAINTENANCE GEK - 31111 D SUPERSEDES GEK - 31111 C S : MAGNE - BLAST CIRCUIT BREAKER t : AM - 13.8 - 50 D - 7 1200 & 2000 AMPERE WITH MM 3 MECHANISM Contents : 3 INTRODUCTION RECEIVING , HANDLING AND STORAGE . , . . 3 3 INSTALLATION 4 DESCRIPTION OF OPERATION . . 10 . . 14 ADJUSTMENTS GENERAL MAINTENANCE rsi y - w ' / - t 28 m RENEWAL PARTS % GENERAL wT ELECTRIC
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INSTRUCTIONS ANDRECOMMENDED PARTSFOR MAINTENANCE
GEK-31111DSUPERSEDES GEK-31111C
S:
MAGNE-BLAST CIRCUIT BREAKER
t:
AM-13.8-50D-71200 & 2000 AMPERE
WITH MM3 MECHANISM
Contents:
3INTRODUCTION
RECEIVING, HANDLING AND STORAGE . , . . 33INSTALLATION
A Letter Designation B, C, H, K, N used immediately following the model numberindicates basic design features.
INTRODUCTIONvoltage, current, and interrupting ratings are neverexceeded. Since this book is written to includeall ratings of the breaker as well as several designvariations, the instructions will be of a generalcharacter and all illustrations will be typicalunless otherwise specified.
The Magneblast breaker is the removable andinterchangeable interrupting element used in metal-clad switchgear to provide reliable control andpro-tection of electrical apparatus and power systems.
The AM-1308-500 Magneblast Breaker isavail-able with continuous current . ratings of 1200amperes and 2000 amperes in accordance withapplicable industry standards. Refer to the breakernameplate for complete rating information of anyparticular breaker. The nameplate also describesthe control power requirements for that breaker.The application of a breaker must be such that its
PROPER INSTALLATION AND MAINTENANCEARE NECESSARY TO INSURE CONTINUED SAT-ISFACTORY OPERATION OF THE BREAKER.The following instructions will provide completeinformation for placing magne-blast breakers inservice and for maintaining satisfactory operation.
RECEIVINGS HANDLING AND STORAGEReceiving and Handling against condensation, preferably by stor-ing it in a warm dry room, since water
absorption has an adverse effect on theinsulation parts. Circuit breakers foroutdoor metal-clad switchgear should bestored in the equipment only when poweris available and the heaters are in oper-ation to prevent condensation.
2. The breaker should be stored in a cleanlocation, free from corrosive gases orfumes; particular care should be takento protect the equipment from moistureand cement dust, as this combination hasa very corrosive effect on many parts.
3. Unfinished surfaces of rollers, latches,etc., of the operating mechanism shouldbe coated with grease to prevent rusting.
If the breaker is stored for any length of time,it should be inspected periodically to see thatrusting has not started and to insure good mech-anical condition. Should the breaker be storedunder unfavorable atmospheric conditions, it shouldbe cleaned and dried out before being placed inservice.
Each breaker is carefully inspected and packedfor shipment. Immediately upon receipt of thecircuit breaker, an examination should be madefor any damage sustained in transit. If injury orrough handling is evident, a damage claim shouldbe filed immediately with the transportation com-pany and the nearest General Electric Sales Officeshould be notified.
It is expected that due care will be exercisedduring the unpacking and installation of the breakerso that no damage will occur from careless orrough handling, or from exposure to moisture ordirt. Check all parts against the packing list tobe sure that no parts have been overlooked.Storage
It is recommended that the breaker be putinto service immediately in its permanent location.If this is not possible, the following precautionsmust be taken to insure the proper storage ofthe breaker:
1. The breaker should be carefully protected
INSTALLATIONEach breaker has been tested and inspected
before shipment from the factory; however, beforeplacing the breaker in service the following itemsshould be checked to assure that no change has oc-curred during shipment and storage.
1. Remove the box barriers and mechanism coverand make a visual inspection to ascertain that thebreaker and mechanism is in satisfactory condition.Check all bearing surfaces of the mechanism forlubrication.Refer to section on LUBRICATION page16 and Figure 17.
(Cover photo 8034807)These instructions do not purport to cover all details or variations in equipment nor to provide forevery possible contingency to be met in connection with installation, operation or maintenance.
.further information be desired or should particular problems arise which are not covered sufficiently forthe purchaser' s purposes, the matter should be referred to the General Electric Company.
To the extent required the products described herein meet applicable ANSI , IEEE and NEMA standards;but no such assurance is given with respect to local codes an<2 ordinances because they vary greatly.
"CHARGED” and the ratchet wheel does not advance.The spring blocking device can now be removed.3. To assure that the electrical contact connectionshave remained tight, they should be checked duringinstallation as well as during each maintenance in-spection. This check of electrical connections isparticularly necessary on breakers used in nucleargenerating stations and other critical applications.The bolted braid connections on the stationary arcingcontacts shouldbe checked for tightness by removingthe arc chutes as described on page 15.
2. Charge the breaker closing springs manually
using a 5/8" ratchet wrench to turn the driving ec-centric (4) Figurel. Turning the eccentric counter-clockwise will advance the ratchet wheel and com-press the springs.When the springs have reached the fully chargedposition the indicator (1) will read "CHARGED", andthe driving pawl will be raised from the ratchetwheel teeth. Additional turning of the eccentric willnot advance the ratchet wheel.Insert the spring blocking device (6) and manuallydischarge the springs against the pins by pushingthe manual release button (3). The springs are nowblocked and slow closing of the breaker contacts canbe accomplished by again turning the driving eccen-tric with a 5/8" ratchet wrench.
4. Connect the test coupler to the circuit breakerand operate it electrically several times. Checkthe control voltage as described under "CONTROLPOWER CHECK" (Page 14).5. Disconnect the test coupler and before replacingthe box barrier, the primary bushings and otherinsulation should be wiped clean.6. If thebreaker has been stored for a long periodof time, it is recommended that the insulation bechecked with a standard 60 hertz high potential test.Refer to Insulation Test (Page 16).
NOTE: If the breaker secondary wiring is tobe given a hi-potential test at 1500 volts, removeboth the motor leads from the terminal connection.Failure to disconnect the motor from the circuitmay cause damage to the winding insulation.7. Lubricate the silver portion of the ball contactat the top of the breaker bushing and the rear por -tion of the ground shoe, by applying a thin film ofcontact lubricant D50H47.8. Refer to metal-clad instruction book GEH-1802for instructions on inserting the breaker into themetal-clad unit.
During the slow closing operation check to insurethat the mechanism does not stick or bind duringthe entire stroke, that it latches securely in theclosed positioit, and that it trips freely when themanual trip lever is operated. At this time, alsocheck the following adjustments:
a. Arcing contact wipe (Refer to page 10)b. Primary contact wipe (Refer to page 10)c. Primary contact gap (Refer to page 11)
DO NOT WORK ON EITHER THE BREAKER ORMECHANISM UNLESSTHE CLOSING SPRINGS AREBLOCKED AND THE OPENING SPRINGS HAVEBEEN TRIPPED OPEN OR MECHANICALLYBLOCKED. THIS PRECAUTION IS REQUIRED TOPREVENT ACCIDENTAL CLOSING OR TRIPPING
The closing springs should now be unblocked. Ro-tate the driving eccentric until the indicator reads ;
DESCRIPTION OF OPERATION5
0manual close and trip levers on the breaker. Allsecondary connections from the breaker to themetal-clad unit are made through the coupler (1)Figure 2.
A spring release interlock, Figure 3, is providedto discharge both the closing and opening springswhen the breaker is withdrawn from or insertedinto the metal-clad unit.
A positive interlock (3) Figure 4 and interlockswitch (2 ) Figure 2, are provided between thebreaker and metal-clad unit to prevent raisingor lowering of the breaker in the unit while in aclosed position and to prevent a closing operationwhen the breaker is not in either the fully raisedor lowered position. To insure that this interlockwill function during manual, as well as duringelectrical operation of thye equipment, both mech-anical and electrical blocking is provided.
The Magneblast Breaker has two principalcomponents; the breaker element and the operatingmechanism:
The breaker element is three similar poleunits, each of which includes the current carryingparts, main and arcing contacts, interrupter, andan enclosing barrier system that provides insulationbetween poles, or phases and to ground. Theprimary connections to the associated metal-cladswitchgear are made through the ball contacts atthe top of the breaker bushings.
The operating mechanism type ML-13 is ofthe stored energy type designed to give high speedclosing and opening. The mechanism will operateon a-c or d-c voltage as indicated on the breakernameplate. Closing and opening operations arecontrolled either electrically from the metal-cladunit and remote location, or mechanically by the
Spring ChargingWhen the breaker is used interchangeablywith type MS-13 solenoid operated breakers inM-36 metal-clad units, fuses are mounted onthe breaker for protection of the motor andclosing circuit,by "C" or "K" suffix in the breaker nomenclature.
In cases where breakers with type ML-13mechanisms must match and line up with breakershaving type ML-11 mechanisms the spring chargingcircuit for both mechanisms should be fused withBuss Company Fusetrons as follows:
The mechanism has a high speed gear motor(10) Figure 5, that compresses a set of closingsprings through the action of an eccentric, ratchet,and pawl assembly. The rotary action of themotor is converted to a straight stroke throughthe eccentric (11) Figure 4, and a lever thatcarries a spring loaded driving pawl (2) Figure 1.
The pawl advances the ratchet wheel (6)Figure 4 a few degrees each stroke where it isheld in position by the latching pawls (2 ). Whenthe ratchet wheel has been rotated approximately180 degrees the closing spring (12) will be fullycompressed. As the ratchet wheel continues torotate, the spring load will shift over center andattempt to discharge. After a few degrees ofrotation, the closing roller (6) Figure 2, willengage the closing latch (8) and the compressedsprings will be held by the latch until a closingoperation is required. During the last few degreesof the ratchet wheel rotation the power switches (7)
are opened and the driving pawl is raised fromthe ratchet wheel surface. This allows the motorand driving mechanism to coast to a natural stopexpending all residual energy.
During the time the springs are being com-pressed a relay (17) Figure 6, is energized tohold the closing circuit open. The relay remainsenergized until the springs are fully charged andthe control switch contacts are re-set.
Closing Operation
( The breaker can be closed electrically byenergizing the closing solenoid (15) Figure 6, ormanually by pushing the close button (9) Figure 5.In either method the closing latch is rotated fromunder the closing roller to release the closingsprings (9) Figure 2. The energy in the springsis used to rotate a cam (16) Figure 7 and closethe breaker through the operating mechanismlinkage. During the closing operation the mech-anism is trip-free at all times. The breaker isheld closed by the closing prop (14) moving intoposition under the prop pin (13). During the closingoperation the opening springs (4) Figure 4, arecompressed and held readyfor an opening operationwith the trip latch (8) Figure 7 bearing againstthe trip latch roller (9).
When the closing operation of the breaker iscompleted and the closing latch is fully reset,
The closing springs may be charged manuallyif control voltage is lost. A 5/8" ratchet wrenchcan be used to rotate the eccentric in a counterclockwise direction until the indicator reads"Charged" and the driving pawl is raised from theratchet wheel. The use of the ratchet wrenchprovides for maximum safety in the event thatcontrol power is suddenly restored without warning.In this event, the motor drive will override theratchet wrench and continues to charge thesprings.
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Figure 6. (8040933) Control Mechanism
7. Power Switches8. Closing Latch9. Closing Latch Shaft
iroller, permitting the operating mechanism linkageto collapse. The energy stored in the openingsprings is released to provide the required openingspeed for successful interruption of the circuit.
As the breaker opens to interrupt a current,the arc first starts at the arcing contacts (5 & 20)Figure 8, transfers to the arc runner (3 & 8) andenergizes the blow-out coils ( 2 & 7). This actionintroduces a magnetic field between the pole pieces
the contacts of the latch monitoring switch closesto permit the spring charging motor to be energizedand recharge the closing springs.Opening Operation
The breaker can be opened either electricallyby energizing the trip coil (3) Figure 5, ormanually by pushing the trip lever (8). In eachmethod the trip latch is rotated off the trip latch
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Figure 7. (0114C5320) Sectional Side View of Mechanism
(4 & 9) of the interrupter that forces the arcdeeper into the arc chute (6). At the time thearcing contacts part a discharge of air is expelledthrough the booster tube (21) across the arc. Thisair flow assists the arc transfer and interruptionby blowing the arc away from the contacts and intothe arc chute. As the magnetic field forces thearc deeper into the interrupter along the divergingarc runners, the field is progressively increasedby the insertion of each additional blow-out coilinto the circuit.
The arc chute has a series of interleavingceramic fins, Figure 19. As the arc is forcedinto the interrupter it is lengthened in the graduallydeepening serpentine path between the fins sothat the electrical resistance of the arc is rapidlyincreased and its heat is absorbed by the ceramicmaterial. The increased resistance reduces themagnitude and phase angle of the current and atan early current zero the arc cannot re-establishitself and interruption occurs.
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Figure 8. ( 0152C5915 ) Cross Section of Breaker Pole Unit
trip roller (9) causing the mechanism linkageto collapse and the breaker to re-open,closing cam (16) will complete its closing strokeand the springs will re-charge as in a normalclosing operation.
Trip Free OperationThe
If the trip coil circuit is energized whilethe breaker is closing, the trip armature willforce the trip latch (8) Figure 7 away from the
ADJUSTMENTS
All adjustments should be checked duringperiodic inspections and whenever it becomesnecessary to repair or replace parts that havebecome worn or defective while in service. Thefollowing adjustments are listed in the order inwhich they are to be checked after removing thebox barriers and front cover from the breaker.
adjustment is provided. A wipe of less than5/16" is an indication that the arcing contactsneed to be replaced. When making this check,see that there is clearance between the arcingcontact (5) and the slot in the throat baffle (7)during entire stroke of the moving contact assembly.Primary Contact Wipe
DO NOT WORK ON EITHER THE BREAKEROR MECHANISM UNLESS THE CLOSING SPRINGSARE BLOCKED AND THE OPENING SPRINGSHAVE BEEN TRIPPEDOPEN OR MECHANICALLYBLOCKED.PREVENT ACCIDENTAL CLOSING OR TRIPPING.
Refer to Figure 9, when the breaker is closedthe stationary primary contacts (1) should risefrom 1/4" to 5/16". Before checking this dimen-sion be sure the mechanism is re-set so that theprop pin (13) Figure 7 is resting on the prop.To obtain the proper contact adjustment, openthe breaker and. referring to Figure 10, loosenthe check nut (4) and turn the adjusting nut (3).Screwing up on the adjusting nut will decreasethe primary contact wipe, down will increase it.Tighten the check nut, close the breaker andrecheck the wipe. With the primary contact wipecorrectly adjusted, the clearance between thecontact arm (6) Figure 9 and the buffer block (3)should be 1/16" or greater when the breaker isfully closed.
THIS MEASURE IS REQUIRED TO
Arcing Contact Wipe
Refer to Figure 9. Close the breaker untilthe arcing contacts just touch. This can bedetermined with the use of a circuit continuitytester such as a light indicator or bell set. Inthis position, the gap between the stationaryprimary contacts (lj and the movable primarycontact (2) should be 5/16" or greater. Thissetting has been made in the factory and no
Primary Contact Gap a film of grease on the latch, closing the breakerpart way, and tripping. The mechanism has theproper trip latch wipe when the latch rests againstthe stop pin (23). No adjustment is provided anda visual inspection is usually all that is required.If this setting is not correct, look for insufficienttravel of the trip shaft (7 ).
Refer to Figure 10. With the breaker closed,press the manual trip button allowing the breakerto trip open normally. Do not force the contactsopen wider by hand. The gap between the sta-tionary primary contacts (5)primary contact (8) measured between the closestpoints, should be 5-1/8” to 5-9/16". To changethis gap, loosen the check nut (17) Figure 7, andturn the adjusting nut (18) on stud (19). Screwingthe adjusting nut down will decrease the primarycontact gap. Tighten the check nut and re-measure the contact gap (close and trip thebreaker before checking the measurement).
WHEN WORKING ON THE MECHANISM INTHE CLOSED POSITION, KEEP FINGERS CLEAROF THE LINKAGE, AS ACCIDENTAL TRIPPINGCAN CAUSE SEVERE INJURY.Trip Latch Wipe
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and the movable
Trip Armature Travel
* Refer to Figure 7. The trip armature (4) shouldhave 1/16" to 3/16" travel before the trip latch (8)starts to move, plus 1/32" minimum overtravelafter tripping. This can be adjusted by moving thetrip coil support (2) and/or by adjusting the trip armscrew (10) Figure 11. A locking screw locatedbehind the trip arm screw must first be loosened.Retighten locking screw after making adjustment.Closing Latch Wipe
Refer to Figure 6. The wipe between theclosing latch (8) and roller (6) should be 3/16"to 1/4". If re-setting is required, loosen, set,and retighten adjustment nut and screw (10).
Refer to Figure 7.latch (8) on the trip roller (9) should be from3/16" to 1/4". This can be measured by putting
The wipe of the trip
Closing Latch Monitoring Switch
The closing latch mustbe fully re-set and the latch monitoring switch(13) operated before the motor will start. Whenthe latch is fully reset the clearance between theswitch striker arm and the switch mounting bracket(14) is l/32" or less, this can be adjusted bybending the striker arm.
Refer to Figure 6.
Motor and Relay Switches
Refer to Figure 6. With the closing springsblocked rotate the switch cam (2 ) until th‘e switchstriker (3) has traveled the maximum amount(about 180 degrees rotation of cam),point the clearance between the striker and theswitch support (5) should be 1/32" or less. Thiscan be adjusted by loosening the switch supportmounting bolts (4) and rotating the support.
At this
Interlock Switch Wipe
Refer to Figure 12. With the positive inter-lock in the reset, or normal position the clearancebetween the interlock switch arm (2)and the switchmounting plate (3) should be 1/32" or less. Thiscan be adjusted by bending the switch arm.: Figure 10. (8038802) Adjustable Coupling For
Making Primary ContactWipe Adjustments.
Driving Pawl Adjustment
Refer to Figure 4. The driving pawl (8)must advance the ratchet wheel (6) sufficientlyon each stroke to allow the latching pawls (2 )to fall into the ratchet teeth. This should bechecked with the closing spring load against thedriving members. With the mechanism unblocked,hand charge the closing springs with the manual
AUXILIARY DEVICEScharging wrench until they are slightly more thanhalf charged. Slowly rotate the charging wrenchuntil the driving pawl has traveled through itsreturn stroke and check the maximum clearancebetween the pawl and the ratchet tooth. Rotatethe charging wrench until the driving pawl hasadvanced the ratchet tooth to its maximum travel.Now check the clearance between the ratchet toothand the latching pawl. The clearance should beapproximately equal for both the driving andlatching pawls and not less than .015" in eithercase.
Latch Checking Switch *Refer to Figure 13. Charge the closingspringssufficiently to reset the mechanism linkage. Ro-tate the trip latch (4) by pressing manual triplever to open the latch checking switch (2). Allowthe trip latch to reset slowly and determine thepoint at which the contacts are made by usinga circuit continuity tester (light indicator, bellset, etc). The contacts of the latch checkingswitch should just make when the gap between thetrip latch (4) and the stop pin (5) located on thelatch roller link (7) is 1/16". There should bea minimum of 1/64" between the switch arm (3) ^and the switch support (1). To obtain adjustmentof the latch checking switch, bend the latch checkingswitch arm (3).Plunger Interlock
Refer to Figure 14. With the breaker in theclosed position, the vertical distance "A" from thetop of the plunger bolt (1) to the bottom of thebreaker lifting rail (3) should be 11-7/32" to11-11/32". To change this adjustment add orremove washers (2).
If adjustment is required for either pawl thesprings must first be fully charged and blocked.Loosen seven motor support bolts (1) Figure 15,and move entire motor assembly to the rear ifthe clearance is under the minimum at the latchingpawls, and to the front if the clearance is underthe minimum at the driving pawl. Move the motorassembly approximately twice the dimensionalincrease required at the pawl. Be certain themotor assembly is moved straight forward or •
rearward and tighten the one bolt on the rightside of the mounting frame first to assure properalignment. After tightening the remaining boltsthe springs should be released and the clearanceagain checked as described above.
On breakers with "C"and "K" suffix, a setof protecting fuses is mounted on the front of thebreaker. These fuses are the primary protectivedevices for the closing control circuit on thosebreakers that are used in metal-clad units de-signed for solenoid operated breakers.Inspection and Test
1. For ease in reviewing the adjustments, thefollowing are recapitulated:a. Primary contact wipe: 1/4" to 5/16".b. Arcing contact wipe: 5/16" or greater
gap at primary contacts.c. Primary contact gap: 5-1/8" to 5-9/16".d. Trip latch wipe: 3/16" to 1/4" with trip
latch resting against stop pin.* e. Trip armature travel: 1/16" to 3/16" plus
1/32" minimum overtravel.f. Closing latch wipe: 3/16" to 1/4".
when the tip on the movable arcing contact istangent to the lower surface of the probes on theupper runner. Proper servicing and lubricationof the breaker and its operating mechanism shouldmaintain these speeds and no adjustment is pro-vided.
Motor and relay switch: maximum clear-ance 1/32".h.Interlock switch: maximum clearance1/32".i.Driving and Latching Pawl:clearance to ratchet teeth .015".minimum3- Control Power Check
After the breaker has been operated severaltimes with the manual charging wrench and themechanism adjustments are checked as described,the operating voltages should be checked at theclosing coil, trip coil, and motor terminals. Con-trol Power for electrical operation of the breakermay be from either an alternating or directcurrent source. The operating ranges for theclosing and tripping voltages as given on thebreaker nameplate, are as follows:
Latch checking switch contacts make whenthe gap between the trip latch and the stoppin is 1/16".
k.
2. Check all nuts, washers, bolts, cotter pins,and terminal connections for tightness.
3. Inspect all wiring to make sure thatno damagehas resulted during installation, and test forpossible grounds or short circuits.,
4. See that all bearing surfaces of the mechanismhave been lubricated. Refer to the section onLUBRICATION. (Page 16 and Figure 17).
5. Operate the breaker slowly with the manualcharging wrench and note that there is noexcessive binding or friction and that thebreaker can be moved to the fully opened andfully closed positions.
6. See that any place where the surface of thepaint has been damaged is repainted immed-iately.
7. Check the trip coil plunger and the closingcoil plunger to see that they move freely.
Opening and Closing Speeds
The closing speed of the arcing contact of thebreaker should be a minimum of llfeetper second.This represents the average speed of the movablearcing contact from a point 3" before the tip istangent to the lower surface of the probes on theupper arc runner to the tangent position.
The opening speed of the arcing contact shouldbe a minimum of 15 feet per second. This repre-sents the average speed over 3" from the point
NominalVoltage
ClosingRange
TrippingRange
14 30v d-c60v d-c
125v d-c140v d-c250v d-c280v d-c125v a-c250v a-c
24v d-c48v d-c
llOv d-c125v d-c220v d-c250v d-c115v a-c230v a-c
2*834 - 50v d-c80 - 115v d-c90 - 130v d-c
160 - 230v d-c180 - 260v d-c
95 - 125v a-c190 - 250v a-c
6070
120140
95190
If the closed circuit voltage at the terminalsof the coil or motor does not fall in the specifiedrange, check the voltage at the source of powerand line drop between the power source andbreaker.
When two or more breakers operatingfrom thesame control power source are required to closesimultaneously, the closed circuit voltage at theclosing coil or motor of each breaker must fallwithin the specified limits.
Electrical closing or opening is accomplishedby energizing the closing or trip coil circuit.Control switches are provided for this purposeon the metal-clad unit. It is also possible totrip or close the breaker manually by pressingthe manual trip lever (8) Figure 5 or the manualclose button (9).
GENERAL MAINTENANCE
GENERAL
Safe and dependable service from electricalapparatus and power systems is contingent uponreliable performance of power circuit breakers.To obtain maximum reliability the breaker shouldbe inspected and maintained on a regular schedule.The breakers are designed in accordance withapplicable standards which require that they becapable of performing up to 5000 operations for1200 ampere breakers and 3000 operations for2000 ampere breakers switching rated continuous
current before any replacement of parts shouldbe necessary. This requirement is based on thebreakers being serviced, or maintained, at leastevery 2000 operations, or once per year, which-ever comes first. If the breaker is also requiredto interrupt fault currents during this period oftime additional maintenance and replacement ofparts may be necessary.
BEFORE ANY MAINTENANCE WORKIS PER-FORMED, MAKE CERTAIN THAL ALL CONTROLCIRCUITS ARE DE-ENERGIZED AND THAT THE
subjected to the severe heat of an arc.These cracks do not interfere with theoperation of the device in any way andshould be disregarded.
3. If the arc chute has suffered any mechan-ical injury due to dropping or accidentalstriking, resulting in the actual breakingoff of fins, replacement will be necessary.Small broken corners on the exhaust endof the arc chute sides will not interferewith its performance and can be dis-regarded.
4. The plastisol flexible coveringfor the polepieces (3 & 8) Figure 18 and the uppermounting support (12) should be inspectedfor breaks in the insulation. If there areholes or breaks in the insulation theyshould be repaired or the part replaced.
Electrical Connections
BREAKER IS REMOVED FROM THE METAL-CLAD UNIT. DO NOT WORK ON THE BREAKEROR MECHANISM WHILE IN THE CLOSED POSI-TION UNLESS THE PROP AND TRIP LATCH HAVEBEEN SECURELY WIRED OR BLOCKED TO PRE-VENT ACCIDENTAL TRIPPING. DO NOT WORKON THE BREAKER OR MECHANISM WHILE THESPRINGS ARE CHARGED UNLESS THEY ARESECURED IN THAT POSITION BY THE MAIN-TENANCE SPRING BLOCKING DEVICE.
§
PERIODIC INSPECTION
The frequency of the inspection and main-tenance operations required should be determinedby each operating company and will depend onthe application of the breakers and the operatingconditions. Factors which should be consideredare: Importance of the breaker to overall plantor system operation; number of operations andmagnitude of currents switched by breaker; fre-quency of fault interruptions; and the atmosphericconditions in which the breaker normally operates.Extreme conditions of dust, moisture, corrosivegases etc., can indicate that inspection and main-tenance will be required more frequently thanevery 2000 operations. Very clean dry operatingconditions with low current switching duty canjustify a longer period of time between inspections.Any time a breaker is known to have interrupteda fault at or near its rating it is recommendedthat the breaker be inspected and necessarymaintenance be performed as soon after theinterruption as is practical. It is also recom-mended that an initial inspection be made of newbreakers after the first 500 operations or sixmonths after being put in service, whichevercomes first.
§
To assure that the electrical connectionshave remained tight, they should be checked duringinstallation as well as during each maintenance in-
#
The following instructions give the itemsthat should be included in an inspection andgeneral recommendations on the maintenance ofbreakers.Interrupters
Since there are no moving parts, the inter-rupters of a magneblast breaker will normallyrequire little or no inspection unless there isevidence of damage to the arc chutes sides orcontamination in the throat area. If either of theseconditions are present the interrupters shouldbe removed from the breaker and the followingpoints noted:
The throat area of the interrupter shouldbe cleaned with sandpaper (Do Not Useemery cloth or other metallic abrasives).All flat areas on either side of themovable arcing contact travel should besanded. Do not sand or otherwise attemptto clean the ceramic fins of the arcchute sides or throat pieces. Heavilycontaminated parts should be replaced.Cracks which have formed in the fins ofthe arc chute are to be expected inceramic materials of this type when
spection. This check of electrical connections isparticularly necessary on breakers used in nucleargenerating stations and other critical applications.The bolted braid connections on the stationary arcingcontacts shouldbe checked for tightness by removingthe arc chutes as described on page 15.Interrupter Removal And Replacement
ADJUSTMENTS.Mechanism
A careful inspection should be made to checkfor loose nuts, bolts, and loose or damaged setscrews or other locking devices. All cam, roller,and latch surfaces should be inspected for anyevidence of damage or excessive wear. Lubri-cate the mechanism as outlined below, then, usingthe manual charging wrench, open and close thebreaker several times to make certain that themechanism operates freely throughout its entirestroke. Check the mechanism adjustments asspecified under ADJUSTMENTS. Check the control , 0wiring for tightness of connections and damagedinsulation.
j
Refer to Figure 16. An arc chute lifter isnormally furnished with the metal-clad switchgearfor use in removing and replacing the interruptersof the AM-13.8-500 breakers. When the lifter isnot available an overhead crane or portable hoistmay be used. The arc chute lifter is assembledto the top plate of the breaker as shown in thereference figure using the bolt (5) located betweenthe front and rear bushings. Before assemblingthe lifter on the breaker it is necessary to removethe box barrier.
Lower the grappling hooks (6) by turningthe handle (1) until they can be placed over thelifting bolts (9) on the interrupter,handle to raise the hooks until they begin tolift the interrupter.
To remove the interrupter, loosen the twoupper supporting bolts (11) and the one lowersupport bolt (16) using a standard 3/4" wrench.Raise the assembly approximately 3/8"and continueto raise the interrupter and gently move it fromside to side until both upper and lower supportsare disconnected,arc chute lifter towards the rear of the breakerand lower the interrupter to a resting positionon the floor. Support the interrupter from fallingover and remove the grappling hooks.
To reassemble the interrupter to the breaker,rest the lower interrupter support (18) on thesupport bracket (17). Slide the arc chute forward,lifting it slightly to engage the supporting bolts (11)in the slots of the upper interrupter support.Check to assure that the upper insulation (16) Figure18, is properly positioned within the throat barrier(9) Figure 23.
Tighten the supporting bolts (11) and (16)Figure 16. These bolts serve as both the elec-trical and mechanical connections between thebushings and the arc runners within the interrupter.Check that the movable arcing contact (14) passesbetween the probes on the upper arc runner(4)Figure 20 without touching.Breaker Contacts
;
Bushings and Insulation
The surface of the bushings should be keptclean and unmarred to prevent moisture absorption.If the insulation surface should become damaged,it should be sanded and cleaned, and should berefinished with either clear varnish or clear resin.Allow to dry smooth and hard.
All other insulation parts on the breaker shouldbe kept clean and dry. Smoke or dust collectedbetween inspection periods should be wiped off,and if dampness is apparent, heaters should beinstalled in the metal-clad switchgear to insuredryness.Insulation Test
Turn the
9s’Move the trolley (3) of the
When insulation has been repaired or re-placed, or when breaker has been operating inadverse moisture conditions, it is recommendedthat the insulation be checked before the breakeris placed back in service. A standard 60 hertzhigh potential test at 27,000 volts RMS for oneminute will normally indicate whether the breakeris satisfactory for service. With the breakercontacts in the fully opened position, apply thetest potential to each terminal of the breakerindividually with all other terminals and thebreaker frame grounded. After high potentialtests are made on organic insulating materials,these materials should be inspected for visibleieakage current paths, and necessary action mustbe taken to repair or replace insulation thatmay have been affected by moisture absorption.
If the breaker secondary wiring is to begiven a hi-potential test at 1500 volts, removeboth of the motor leads from the terminal board.Failure to disconnect the motor from the circuitmay cause damage to the winding insulation.Lubrication
By removing the box barrier the movable andstationary primary contacts and the movable arc-ing contacts can be inspected. The stationaryarcing contacts can be inspected only after re-moving the interrupter. If the contacts are burnedor pitted, they can be made smooth with a fine file.
After completing inspection of the contacts,check the contact adjustments as specified under
In order to maintain reliable operation, itis important that all circuit breakers be properlylubricated at all times. Some of the bearingsand rolling surfaces utilize a new type of drylubrication that will require no maintenance and
will last the life of the equipment. The remainingbearings and surfaces require lubrication as listedin the lubrication chart, Figure 17. These havebeen properly lubricated during assembly at thefactory, using the finest grades of lubricantsavailable.greases have a tendency to oxidize with age, asevidenced by hardening and darkening in color.Elimination of the hardened lubricant is essentialfor the proper operation of circuit breakers.Also frequent operation of the breaker causesthe lubricant to be forced but from between thebearing surfaces. A simple lubrication will oftenclear up minor disturbances which might bemistaken for more serious trouble.
A definite lubrication schedule should beset up taking into consideration the frequency ofoperation of the breaker and local conditions.It is recommended that lubrication of thebreaker and its operating mechanism be a partof theperiodic inspection and maintenance program,with not more than a two year period betweenlubrications. It is also recommended that all
circuit breakers be operated at regular intervals,at least once a year, to insure the lubricationis in good condition and the breaker is operable.The lubrication chart, Figure 17, is dividedinto two methods of lubrication. The first methodoutlines the maintenance lubrication which shouldbe performed at the time of periodic mainte-nance, and requires no disassembly. The secondmethod outlines a lubrication procedure similarto that performed on the breaker at the factory,
and should be used when a general overhaul ofthe breaker is necessary.General Electric Lubricants D50H15 andD50H47 are available in 1/4 lb. collapsible tubes.It is so packaged to insure cleanliness and toprevent oxidation.
However, even the finest oils and
METHOD OF CLEANINGBEARINGS
Whenever cleaning of bearings is required,as indicated in the lubrication chart, the followingprocedures are recommended.
ALTERNATE LUBRICATION(REQUIRES DISASSEMBLY)
LUBRICATION ATMAINTENANCE PERIODPARTS
Prop & Trip Shaft Bearings(Teflon coated bearings) No lubrication required No lubrication required
Remove bearings or links,clean per instructions andapply D50H15 lubricant liberally.
Light application of machineoil SAE 20 or SAE 30.Sleeve Bearings - main crank shaft,
mechanism pawls, spring chargingand operating linkages, etc. (Bronze)
Contact Arm Hinge AssemblyCup BearingLoose rings between bushing andcontact arm
No lubrication required Wipe clean and apply D50H47.
Roller and Needle Bearings Light application of machineoil SAE 20 or SAE 30. Clean per instructions and repack
with D50H15 lubricant.Ground surfaces such as cams, ratchetteeth, etc.(Surfaces coated withMoS2)
No lubrication required No lubrication required
Ground surfaces such as latches,rollers, prop, etc. Wipe clean and apply
D50H15 lubricantWipe clean and applyD50H15 lubricant.
Silver plated contacts and primarydisconnect studs
Wipe clean and applyD50H47 lubricant
Wipe clean and applyD50H47 lubricant.
Booster Cylinder Do not lubricate Do not lubricateArcing Contacts Do not lubricate Do not lubricate
the alcohol is perfectly clean, and do not allowthe bearings to remain in the alcohol more thana few hours. If it is desirable to leave the bearingsin the alcohol for a longer time, an inhibitedalcohol such as is used for anti-freeze should beused. Even then the bearings should be removedfrom the alcohol within twenty-four hours. Pre-cautions against the toxic effects of the alcoholmust be exercised by wearing rubber gloves andby using the alcohol in a well ventilated room;excessive exposure to the fumes is sometimesunpleasant to personnel. Washing the bearings inthe light oil, draining and repacking with lubricantD50H15 should follow immediately.
Bearings that are pressed in to the frame orother members such as the motor support (9)Figure 15, should not be removed. After removingthe shaft and inner race the bearing can be cleanedsatisfactorily with petroleum solvent or a similarcleaner and a stiff brush. Follow the procedureoutlined above using a light machine oil and G-Elubricant D50H15 before reassembling the innerrace and shaft.Rolling Surfaces
A number of rolling and rubbing surfaces inthe mechanism have been lubricated with a baked-on dry, molybdenum disulfide coating,lubrication, which can be recognized by its dark,
almost black color (e.g. Face of switch cam (5)Figure 2) requires no maintenance and shouldlast the life of the breaker.
Other rolling or rubbing surfaces that are notlubricated with molybdenum disulfide should havethe dried, dirty grease removed and a thin filmof fresh lubricant D50H15 applied.
MAINTENANCE
bleeve Bearings
The sleeve bearings used in the prop (14)Figure 7 and the bearings for the trip shaft (7)utilize Teflon surfaces and do not require lu-brication.surface will acquire a thin black film. Do notremove this film unless there is evidence ofout-side contaminates, such as dry or hardenedgrease. If contaminants are present they shouldbe removed by immersing the prop and bearingin clean petroleum solvent, or similar cleaner,and using a stiff brush. Do not remove the bearingsfrom the prop or frame. DO NOT USE CARBONTETRACHLORIDE.
After a number of operations, the
The remaining sleeve bearings located in thedriving element and the mechanism linkage andframe should be cleaned and relubricated withG-E D50H15 lubricant at general overhaul periods.This includes the bearings in the driving link (8)Figure 15, driving pawl lever (10) Figure 4,driving pawl (8), latching pawls (2), trip latchroller support (10) Figure 7, cranks (12), and thebearings in the mechanism frame and intercon-necting links. Bearings that are pressed into theframe or other mechanism members should notbe removed.
The cup bearing (18) Figure 8 of the primarycontact arm should be disassembled, cleaned,and lubricated with G-E D50H47 lubricant at gen-eral overhaul periods.
The main shaft bearings (24) Figure 7 shouldbe removed, cleaned, and lubricated with G-ED50H15 lubricant at general overhaul periods.Roller and Needle Bearings
This
Refer to Figure 7. Bearings in the camfollower (6), latch roller (9), and camshaft bearings(25) should be removed from the mechanism andthe inner race disassembled. They should then beplaced in a container of clean petroleum solventor similar cleaner.TETROCHLORIDE.has become badly oxidized, it may be necessaryto use alcohol (typeto remove it. Ordinarily, by agitating the bearingsin the cleaning solution, and using a stiff brushto remove the solid particles, the bearings canbe satisfactorily cleaned. Do not handle thebearings with bare hands as deposits from theskin onto the bearings are inductive to corrosion.If the bearings are touched, the contaminationcan be removed by washing in alcohol. After thebearings have been thoroughly cleaned, spin themin clean new light machine oil until the cleaneror solvent is entirely removed. Allow this oilto drain off and then repack them immediatelywith G-E lubricant D50H15 being sure all metalparts are greased. The inner races should beassembled.
Magne-Blast breakers used for switching arcfurnaces or capacitors will require more frequentand more detailed inspection and maintenancebecause of the repetitive nature of the applications.The following schedule is recommended for suchbreakers:
DO NOT USE CARBONIf the grease in the bearings
used for thinning shellac)A. Every 500 Operations:
ft.1. Remove the box barriers. '#}
Wipe all insulating parts clean ofsmoke deposit and dust with a cleandry cloth, including the bushings, andthe inside of the box barriers.
2.
3. All flat parts in the throat area ofthe interrupters should be thoroughlycleaned by using sandpaper. Thiscleaning should be performed anytime the interrupter is removed. Thearc chute sides and throat cooler finsshould not be cleaned. Whenever theinterrupter is removed, loose dust anddirt should be blown out before re-If it becomes necessary to clean
the bearings in alcohol (shellac thinner), be sureNOTE:
placing arc chutes. Throat coolerswhich are heavily contaminated shouldbe replaced.Check the breaker and mechanismadjustments as summarized underINSPECTION AND TEST. The neces-sary readjustments should be madeas described under ADJUSTMENTS.
6. Lubricate the breaker operating mech-anism in accordance with instructionsunder LUBRICATION, page 16 andthe lubrication chart Figure 17.Inspect all wiring for tightness ofconnections and possible damage ofinsulation.
4.7.8. After the breaker has been serviced,
it should be operated manually to besure there is no binding or frictionand that the breaker contacts canmove to the fully opened and fullyclosed positions. Its electricaloper-ation should then be checked usingeither the test cabinet or the testcouplers.
C. After Every 10,000 Operations:
1. In addition to the servicing done each2000 operations, the interruptersshould be removed from the breakerand disassembled to permit a detailedinspection of insulation, blow-outcoils, arc runners and assemblieswhich can become contaminated byarc products. ,
2. The blow-out coils should be care-fully examined and if the insulationhas been cracked, shrunk or erodedfrom arc action and heat so that theturns of the coils are not fully in-sulated from each other, the coilsshould be replaced. All connectionsshould be checked for tightness.
3. The arc runners should be inspectedand replaced when the arc resistantcoating on the runner surface has beenpenetrated as a result of arcerosion.
4. Check the stationary arc contacts toassure that the arcing contacts are ingood condition and that their con-nections are tight.
5. Insulating material that is carbonizedand cannot be satisfactorily cleanedshould be replaced.
B. Every 2000 Operations, or Every SixMonths Whichever Comes First:1. In addition to the servicing done each
500 operations, the following inspec-tion should be made and work donewhen required.
2. Primary Contacts (3 and 10 FigureInspect the condition of the23).
stationary contact fingers and mova-ble contact blocks. Badly pitted orburned contacts should be replaced.(Note: Burned primary contacts in-dicate the probable need for arcingcontact replacement.) If the contactsurfaces are only roughenedor galled,they should be smoothed with crocuscloth or draw filed. After contactdressing the primary contacts shouldbe greased lightly with D50H47.
i
!
!
3. Arcing Contacts (5 and 20 Figure 8).When the arcing contact wipe is lessthan the minimum specified underADJUSTMENTS, the contacts shouldbe replaced. The contacts should beinspected for uneven wear and/ordamage using a mirror to inspectthe stationary contacts. Normallyit will not be necessary to removethe interrupters for this 2000 opera-tion servicing unless inadequate wipeor contact condition indicate a needfor replacement. If the interruptersare removed, the contact braids, andother parts subject to arcing shouldbe checked for possible cleaning orreplacement. Do not grease thearcing contacts under any circum-
I
I
stances.4. The breaker and operating mechanism
should be carefully inspectedfor loosenuts, bolts, and loose or damaged setscrews or other locking devices. Allcam, latch and roller surfaces shouldbe inspected for damage or excessivewear. The buffer blocks and theirretainers on the bottom of the sta-tionary contact support should beinspected for possible need of re-placement.
5. The contacts of the control relay (17)Figure 6, should be inspectedfor wearand cleaned if necessary.
6. Any parts damagedor severely burnedand/or eroded from arc action shouldbe replaced.NOTE: Fine cracks may develop inthe fins of the arc chute sides. Thisis to be expected with ceramic mate-rials when subjected to the high heatof an arc and may be disregardedunless they are long and present apossibility of fin sections breakingcompletely off. Small broken cornerson the exhaust end of the arc chutewill not interfere with its performance
in the blocked position, remove the box barriers(1) Figure 8.assembled to the breaker and the interrupterremoved as described under INTERRUPTER RE-MOVAL AND REPLACEMENT page 16.
To disassemble the arc chute after it hasbeen removed from the breaker, proceed asfollows:
and can also be disregarded.7. The cup bearing and the contact ring
at the hinge point of the contact bladeshould be disassembled, inspected,cleaned, and relubricated with G-Econtact lubricant D50H47. The contactring should be inspected for wear andreplaced when reduced in thickness toless than 1/32". When reassemblingthe cup bearing, be sure the cotterpin isproperly assembled in the castlenut on the hinge pin (7) Figure 23.This assures proper contact pressureat the hinge.
D. Every 20,000Operations or ApproximatelyEvery Five Years - Whichever ComesFirst:
The arc chute lifter can now be
NOTE: When disassembling the arc chuteand its components some small washers, spacers,etc., will be found that cannot be identified inthese instructions. Care should be taken tocollect and identify these items so they can bereassembled correctly.
1. Remove the assembly bolts (2, 6, 9, 11,15, 17 and 19), Figure 18.
2. Remove the side brace (7) and upperbrace (5), the upper pole pieces (3), thelower pole pieces (8).
3. To remove the upper supports (12), andupper interrupter support (14) removethe assembly bolts (1 and 13), and thebolted connection between the upper in-terrupter support and the blow-out coil.
4. Remove the assembly bolt (22) to removethe lower brace (10).
5. Remove the lower interrupter support(20) by removing the assembly bolts (21)Figure 18 and the connection nut (8)Figure 20.
6. At this point, the side shields (5) Figure20 and the upper arc runner assembly
can be removed. The throat coolersFigure 19 are permanently affixed
to the side shields.
t
The breaker should be given a generalinspection and overhaul as required.All excessively worn parts in boththe mechanism and breaker should bereplaced. Such wear will usually beindicated when the breaker cannot beadjusted to indicated tolerances. Thisoverhaul and inspection is more de-tailed and will require disassembly ofmechanism and breaker operatingparts.All roller and needle bearings in theoperating mechanism should be dis-assembled, cleaned, and repackedwith G-E lubricant D50H15 as de-scribed under LUBRICATION.
1.
2.
3. The stationary primary contact fin-gers (3) Figure 23, should be dis-assembled and the silver-platedpivotarea of the contact and contact supportcleaned and lubricated with G-E lu-bricant D50H47.
(2 )(7 )
7. Further disassembly of both the upperand lower arc runner assemblies can bedone by removing the various screwsand assembly bolts (not illustrated) asshown in Figure 19.The arc chute sides (6) Figure 19, canalso be separated for inspection.
Reassemble the interrupter in the reverseorder. The following items should be noted duringreassembly:
The breaker and operating mechanismshould be serviced as described forevery 2,000 operations and properlyadjusted before being put back intoservice.
4.
8.REPAIR AND REPLACEMENT
This section covers the proper method ofremoving and replacing those parts of the breakersubject to damage and wear that may requirerepair or replacement at the installation. IM-PORTANT: UPON COMPLETIONOF ANY REPAIRWORK, ALL BREAKER AND MECHANISM AD-JUSTMENTS MUST BE CHECKED. Refer to thesection on INSTALLATION, paying particularattention to ADJUSTMENTS and FINAL INSPEC-TION.ARC CHUTE (To inspect or replace blow-outcoils and arc runners):
With the breaker open and the closing springs
The fins of the arc chute sides should beequally spaced and aligned before boltingtogether. The front edge (along therunner) of the two arc chute sides shouldbe parallel and in line.The gap between the fins at the rear ofthe arc chute sides measured at least1" in from the back end of the arc chute(See Figure 21) should be1/16"maximum.
3. Check to insure that electrical connectionsto the blow-out coils are tight.
4. When reassembling the arc runner as-semblies, check that the spacers (5 and12) Figure 19 are correctly installed.
5. Before bolting the upper supports inplace, make certain that the upper arcrunner assembly is tight against the arcchute side so that the gap between theupper insulation and the arc chute sides(6) is a minimum. The throat coolers(7) shouldalsobe assembled tightly againstthe arc chute sides.
6. Make certain that the electrical con-nections are tight.
Reassemble the interrupter on the breaker asdescribed under INTERRUPTER REMOVAL ANDREPLACEMENT, page 16.CONTACTS
2S
f
3*Siocoa. 4a.3</J
mozz3- 5O N$p$ rv“ mot CM ILU>o 6xh-o mzUJ Open the breaker and remove the boxbarriers
and interrupters as previously described. Toremove the contacts, proceed as follows:
A. Stationary Arcing Contacts (10) Figure 22.1. Disconnect the contact braids (7)
from the contact fingers by removingtwo bolts and locking plates (8).
2. Grasp the lower end of the contactfingers with pliers and pull contactassembly downward to remove fromstud assembly.
3. To disassemble braids from studplate remove one bolt (5).
4. To disassemble stud plate from con-tact support, remove two bolts (6).
5. Reassemble in the reverse order,make sure lockingplates areproperlyreassembled with bolts (8).
B. Movable Arcing Contact (14) Figure 23.1. Remove the assembly bolts (12) mak-
ing note of quantity and location ofshims and spacers used between con-tacts and contact arms.
2. Reassemble in reverse order, re-using the shims and spacers.Close the breaker slowly to checkthat the movable arcing contact isapproximately centered on the sta-tionary arcing contact and that itdoes not rub on either side of thethroat barrier (9).NOTE:essary to replace arcing contacts on
3.
Whenever it is found nec-Figure 21 (8029373) Arc Chute Fin Spacing
1. Rear Bushing2. Guide and Support for Interrupter3. Bolts for Contact Support4. Contact Support5. Bolt for Flexible Braid6. Mounting Bolt7. Flexible Braid8. Connection Bolt9. Stud for Mounting Arcing Fingers
3. Raise the contact finger to clear theprimary contact stop plate (8) andlift the finger out of contact support(7). Remove one contact finger ata time.
To replace the Stationary Primary Contacts:
1. Apply a thin coating of D50H47 greaseon the hinged edge of the finger (9)then place it on the contact support
any pole of a breaker it is recom-mended that both the stationary andmovable contacts on that pole bereplaced at the same time.
C. Stationary Primary Contacts (9) Figure 24.1. Compress the contact spring (6) by
use of the spring compressor.2. Remove spring and spring guide (1).
When reassembling, first insert pis-ton tube assembly (13) into the boostercylinder and reassemble the cup bear-ing, making sure the silvered contactwashers between the bushing andcontact arms (both sides) are inplace.Reassemble operating rod pin (4) andconnection bar (15).
F. After disassembly and reassembly of anycontacts, check all contact adjustments asdescribed under ADJUSTMENTS.
4.(7) so that it is retained by stopplate (8).
2. Open spring compressor (3) and as-semble spring guide, spring andspring compressor (Figure 24A).
3. Turn nut (2) in clockwise direction tocompress contact spring (Figure 24B).Hold spring firmly in yoke on springcompressor to prevent spring fromslipping out of the compressor.
4. Place washer (not shown) on guide ontop of spring, place top of guide intohole in spring retainer (4) and theround end of spring guide in cut-out in primary finger (Figure 24C).
5. Hold spring assembly firmly in placeand remove spring compressor.
D. Movable Primary Contacts (10) Figure 23.To replace the movable primary contactson a 1200 ampere breaker proceed asfollows:
1. Disassemble nuts from assemblybolts (11) and remove the movableprimary contacts (10).
2. Reassemble in reverse order.To replace the movable primary contactson a 2000 ampere breaker it is firstnecessary to disassemble the movablearcing contacts, then proceed as follows:
1. Disassemble operating rod pin (4),first noting quantity and location ofwashers in the assembly.
2. Pry contact arms (8) apart enoughto disengage pivot pins of pistonassembly (13) allowing piston to dropdown into its booster cylinder.
3. Rotate the two parts of the contactarm assembly away from each otherso assembly bolts (11) are accessibleand movable primary contacts (10)can be removed.
*
%I
5.
BUSHINGS *IMPORTANT: DO NOT REMOVE ALL SIX
BUSHINGS AT ONCE. The bushings have beencarefully aligned with the breaker frame, duringassembly at the factory, and it is important thatthis alignment be maintained to insure inter-changeability of the breakers in the metal-cladunits. It is, therefore, recommended that thebushings be removed and reassembled one at atime. Also, before removing any one bushing,measure the distance from that particular bushingto adjacent bushings in both directions, so thatit may be reinstalled in the same location.
However, it is possible to remove and re-assemble three bushings at one time. If this ispreferred, alignment of the bushings may beaccomplished by placing the breaker in a de-energized spare metal-clad unit before tighteningthe bushing mounting bolts. This must be donebefore the interrupters are reinstalled.To replace the bushing, proceed as follows:
Rear Bushing
#
Open the breaker and remove the boxbarriers and interrupters as already de-scribed.Remove the horizontal barrier (14) Fig-ure 8.Remove the four bolts at the mountingflange of the rear bushing being removedand lower the bushing assembly.NOTE: Shims may be found between thebreaker mounting plate and the bushingmounting flange on some, or all bolts.These shims are for squaring up thebushing and may be required when newbushings are assembled.Referring to Figure 24, disassemble theprimary contact springs (6) as previouslydescribed.Disassemble the spring retainer (4) byremoving mounting bolts (5).
1.
2.
3.%
4. Reassemble in reverse order.E. Contact Arm Assembly (8, 10, 13, 14)
Figure 23.1. Remove connection bar (15).2. Disassemble hinge pin (7), cup bearing
(6) and operating rod pin (4) notingquantity and location of any washersand spacers used in assemblies.
3. The contact arm assembly includingthe piston assembly (13) can now beremoved.
4.5. EP-.-
6. Referring to Figure 22, disassemble thecontact support (4) and interrupter mount-
3. Remove the two mounting screws of thelower switch.ing bracket (2) removing two bolts (3).
7. Reassemble in the reverse order. Theinterrupter mounting bracket (2) is notsymmetrical and must be assembled cor-rectly to orient the interrupter properlyon the breaker. The longest projectionof the bracket should be toward the lowerend of the bushing.
4. Remove the two mounting screws of thecenter switch.Remove the two mounting screws of theupper switch.Disconnect the lead wires of switch tobe replaced.Reassemble in the reverseorder and checkswitch adjustment as explained underADJUSTMENTS.
5.6.
Front Bushing
7.Open the breaker and remove the boxbarriers and interrupters as already de-scribed.Remove the horizontal barrier (14) Fig-ure 8.Remove the connection bar (15) Figure23, cup bearing (6) and hinge pin (7).Remove the four bolts at the mountingflange of the front bushing being removed,and lower the bushing. (See note underrear bushings concerning use of shims).When reassembling, first mount the bush-ing and assemble the cup bearing (6),contact arm (8), and replace pin (7) beingsure the silvered contact washersbetweenthe bushing and contact arms are in place.The contact surfaces at the hinge pointof the contact blade and bushing shouldhave a thin coating of D50H47 grease.Check all contact adjustments as outlinedunder ADJUSTMENTS.
1.
TRIP SHAFT AND LATCH (See Figure 11)2.Remove spring discharge crank (3), man-ual trip lever (11) and if furnished, thelatch checking switch operating arm (2)from the trip shaft.Disengage trip latch spring (1).Remove three (3) cotter pins from tripshaft.Remove trip arm screw (10) and triplatch set screw (8).Place a block between the trip latch (9)and the left side of the mechanism frame.Drive the trip shaft to the left until thelatch is free of the key, then removethe key.Check for and remove any burrs raisedaround the keyway on the shaft to avoiddamaging the trip shaft bearings.Shaft, latch, etc., may now be removed bydriving it to the left. Note quantity andlocation of washers used as spacers inthe assembly.
1.3.4.
2.3.
5.4.5.
II6.
6.INTERLOCK SWITCH
7.To remove the interlock switch (4) Figure 12,remove the two mounting screws and disconnectthe lead wires. Reassemble in the reverse orderand check the switch adjustments as explainedunder ADJUSTMENTS.
8. Reassemble parts in reverse order. Besure trip latch is aligned in center of triplatch roller and that the latch spring isproperly installed. Check latchadjustmentas described under ADJUSTMENTS.
LATCH CHECKING SWITCH
To remove the latch checking switch (5)Figure 12, (when furnished), remove the twomounting screws and disconnect the lead wires.Reassemble in the reverse order and check theswitch adjustments as explained under ADJUST-MENTS.MOTOR, RELAY AND LIGHT SWITCHES
Two or three switches (7) Figure 6, aremounted in tandem as required by the application.
1. Remove the opening spring per instruc-tions below.2. Remove two mounting bolts (4) from
switch bracket (5).
TRIP LATCH ROLLER BEARING
1. Remove two cotter pins at ends of triplatch roller shaft (8) Figure 13.
2. Partially remove shaft out right side offrame until latch roller (6) is free.i
3. Reassemble in reverse order with properspacing of washers. Be sure latch rollerrotates freely.
CLOSING LATCH Remove shaft out left side of frame.5.1. Remove cotter pins at both ends of clos-ing latch shaft (9) Figure 6.2. Remove spring and paddle (12).3. Remove set screws from latch (8).4. Move shaft (9) to left (away from frame)
by tapping lightly on the inside end ofshaft. Rotate shaft and continue tappinguntil shaft is free. Shaft will push out-side needle bearing from housing.
5. Reassemble in reverse order putting bear-ing into frame last. Use a small pieceof tubing or pipe when inserting bearingto assure proper alignment.
6. Check closing latch adjustments as de-scribed under ADJUSTMENTS.MOTOR SUPPORT
Reassemble in reverse order using thecorrect number of washers and spacersto properly locate the parts.Rotate the mechanism through a closingoperation using the manual chargingwrench. Check the location of the camfollower (6) Figure 7, on the cam (16).If necessary, move the cam to correctthe alignment. Complete the closingoperation and check the location of theprop pin (13) on the prop (14). It shouldbe approximately centered.
6.
7.
TRIP COIL
To replace the potential trip coil (6) Figure11, proceed as follows:
With the breaker in the open position,remove the two mounting bolts (7).Remove trip coil support (5) and spacers.Cut wires at the butt connectors andremove coil.When replacing the coil be sure to as-semble the correct fiber spacers at theends before bolting support (5).Adjust coil location to allow approxi-mately 1/4" of armature travel beforelatch starts to move.
1.
2.1. To remove motor support (9) Figure 15.first remove the closing latch spring (12)Figure 6.
2. Remove the retaining ring (6) Figure 15,and driving link (8).Remove motor leads from the terminalboard.
4. Remove six 3/8" bolts (1) Figure 15,on bottom and one 3/8" bolt on the rightside (not shown).Remove four mounting bolts from motor(not shown).
6. Remove the retaining ring (4) from theeccentric (5).Reassemble all parts of the motor supportin the reverse order and re-align itproperly as described under DRIVINGPAWL ADJUSTMENTS.
3.4.
3.5.
6. Butt connect wires and check operationof solenoid electrically and mechanically.5.
CLOSING COIL
To remove the closing coil (15) Figure 6,proceed as follows:
Block the closing springs as describedin INSTALLATION.
7. 1.2. Remove the left hand closing spring as
described in CLOSING SPRINGS below.§§ CAMRemove two mounting bolts (11), coilsupport (16), and spacers.Cut wires at the butt connectors andremove coil.Replace the coil and the correct numberof fiber spacers before bolting support.Butt connect wires and check that thearmature is not binding. Check coilfor electrical operation.
3.1. Remove two set screws from ratchetwheel (6) Figure 4 and remove wheelfrom main shaft (5).Remove two set screws from switch cam(5) Figure 2.Remove prop reset spring (4) Figure 5.Remove two set screws from cam (16)Figure 7, and move cam to the right onthe shaft as far as it will go. Slide theshaft to the left until key is fully exposed.Remove key and check shaft for burrs.
pushing the manual trip lever or blockthe opening springs with asuitable blockingdevice.
CLOSING SPRINGS
The closing springs (12) Figure 4, can beremoved as follows:
1. Charge the springs with the manual charg-ing wrench and apply the spring blockingdevice as described in INSTALLATION.
2. Discharge springs by pushing manualclose button (9) Figure 5.
3. Rotate cam shaft (5) Figure 4, by usingthe manual charging wrench until the gapbetween the spring (12) and the bearingblock (7) is 2 inches or more.
4. Lift both springs until they clear thelower supports, then pull forward anddown until the top supports are free.
5. Either discharge the opening springs by
OPENING SPRINGS
To remove the opening springs (4) Figure4, proceed as follows:
Charge and block the closing springs asdescribed under INSTALLATION.Push manual trip lever (8) Figure 5, tobe sure the opening springs are fullydischarged.Remove upper pin (1) Figure 4, and lowerpin (9).After reassembling springs check the opengap at the primary contacts as describedunder PRIMARY CONTACT GAP.
1.
2.
3.4.
RENEWAL PARTS
It is recommended that sufficient renewalparts be carried in stock to enable the promptreplacement of any worn, broken, or damagedparts. A stock of such parts minimize serviceinterruptions caused by breakdowns, and savestime and expense. When continuous operation isa primary consideration, more renewal partsshould be carried, the amount depending upon theseverity of the service and the time requiredto secure replacements.
Renewal parts which are furnished may notbe identical to the original parts since improve-ments are made from time to time. The partswhich are furnished, however, will be interchange-able.
ORDERING INSTRUCTIONS
1. Always specify the complete nameplatedata of both the breaker and the mech-anism. •'
2. Specify the quantity, catalog number (iflisted), reference number (if listed), anddescription of each part ordered, andthis bulletin number.
3. Standard hardware, such as screws, bolts,nuts, washers, etc., are not listed andshould be purchased locally.
4. For prices, refer to the nearest officeof the General Electric Company.The listed terms "Right" and "Left"
apply when facing the mechanism end of thebreaker.
NOTE:
*PARTS RECOMMENDED FOR NORMAL MAINTENANCE
In the following tabulations are listed those parts of the breaker and operatingmechanism which are usually recommended for stock for normal maintenance.Other parts can be obtained by contacting the nearest office of the GeneralElectric Company.
** Refer to breaker nameplate or summary for proper voltage rating.Quantity two (2) relays required on special control circuits. Checkbreaker and connection diagram.Furnish 0161A4241P001 for breakers without closing springdischarge mechanism.