Voltage Circuit Breaker

8/19/2019 Voltage Circuit Breaker

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1/30/2016 Air Circuit Breakers : Charging method : Hitachi Industrial Equipment Systems

Home Products Information Switches & Breakers Air Circuit Breakers Charging method

The closing coil is charged by manual charging

handle. For closing, first charge the spring by

using the charging handle, and then press the

close button(I, ON) for closing, the open button(O,

OFF) for opening

When closing spring is completely charged, charge

indicator indicate "Charge"

It is mechanically locked not to press the close

button(I, ON) and open button(O, OFF)simultaneously

Contact condition of the main circuit is shown on

the(O, OFF), (I, ON) indicator.

Air Circuit Breakers : Charging method

Manual charging type

Motor charging type

The closing spring is charged by a motor ON charging method or OFF charging method is availableselectively.

-OFF charging method : When the breaker is opened, the closing spring is charged automatically. It can change

to ON charging method by removing b(A×b) contact like beside circuit diagram

-ON charging method : The closing spring is charged automatically when the breaker is closed.It can change to

OFF charging method by using b(A×b) contact. There is a contact to indicate the charging completion(TS+, TS-).

Since the contact signal of charging completion switch is connected to the external terminal, It is easy to construct

a circuit(ex.Automatic closing circuit) by using that contact

Manual charging is also available

With the breaker closed(I, ON), only manual charging is possible(motor charging cannot be performed)

With the open button(O, OFF) pressed, closing cannot be performed(electrical and mechanical lock)

When OFF Lock device is in use, closing cannot be worked.(electrical and mechanical lock)

Opening should follow at least one second after completion of charging

Pumping prevent circuit is included with the closing coil(electrical lock)

Please note that pumping prevent circuit can be reset when the voltage of input signal drops

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1/30/2016 Air Circuit Breakers : Charging method : Hitachi Industrial Equipment Systems

*1 Since charging completion contact (TS+, TS-) terminal is for contact output power should not be allowed.

*2 Charging completion contact capacity is equal to that high of capacity of auxi liary contact in page 27.

* The range of operating voltage : 85-110%

Note

Motor ratings

Rated voltage Inrush current peak value(A) Steady current(A) Power consumption(W) Charging time(sec)

AC/DC

50/60Hz

110 7 3.5 385

5 Under

220 7 3.5 770

DC

125 7 3.5 437

24 30 11 264

48 30 5.5 264

Note

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3/78

DEH 40368 Instruct iong

PowerVac ® Vacuum Circu

w ith ML-20 Mechanism


4/78

PowerVac ® Vacuum Circuit Breaker

with ML-20 Mechanism

Table of ContentsDescription Page

SECTION 1−−−−Introduction............................................ 4 1.1 Safety.............................................................................. 41.2 Maintenance................................................................... 4

SECTION 2−−−−Description............................................... 52.1 General............................................................................ 52.2 Summary Description...................................................... 5

SECTION 3−−−−Receiving, Handling and

Storage...................................................... 53.1 Receiving........................................................................ 5

A. Equipment Packages................................................. 5B. Inspecting for Damage.............................................. 5

C. Filing a Claim............................................................. 53.2 Handling.......................................................................... 63.3 Storage............................................................................ 6

SECTION 4−−−−Features...................................................... 6 4.1 Safety Precautions........................................................... 64.2 Interlocks......................................................................... 64.2.1 Rating Interference Plate................................................. 64.2.2 Closing Spring Interlock................................................... 64.2.3 Negative Interlock............................................................ 7

4.2.4 Positive Interlock Bar....................................................... 74.2.5 Closing Spring Gag Interlock............................................ 7

SECTION 5−−−−Operation.................................................. 85.1 General............................................................................ 85.2 Close Spring Charging..................................................... 85.3 Closing Operation............................................................ 85.4 Opening Operation.......................................................... 95.5 Trip-free Operation.......................................................... 9

SECTION 6−−−−Control Circuit....................................... 9

SECTION 7−−−−Mechanical Checking and

Slow Closing......................................... 97 1 Visual Inspection 9

Description

SECTION 9−−−−Electrical Check9.1 Electrical Operation...................9.2 High Potential Test....................9.2.1 Primary Circuit...........................9.2.2 Secondary Circuit ......................

9.3 Primary Circuit Resistance........9.4 Vacuum Interrupter Integrity Tes9.5 Insulation Test...........................

SECTION 10−−−−Checking and

Breakers...........

SECTION 11−−−−Maintenance .11.1 General.....................................

11.1.1 PowerVac Interrupter................11.1.2 Trouble Reporting.....................11.2 Service Conditions ....................11.3 Fault Interruptions .....................11.4 Contact Erosion.........................11.5 Transfer Finger Wear................11.6 Mechanism...............................11.7 Primary Insulation Parts.............11.8 Lubrication................................11.9 Recommended Maintenance....

SECTION 12−−−−Timing ................

SECTION 13−−−−Opening and C

SECTION 14−−−−Repair and Re14.1 General.....................................14.2 Replacement of Interrupter Asse14.3 Primary Disconnect Fingers ......14.4 Mechanism...............................14.5 Control Switches.......................14.6 Trip Coil Replacement...............

14.7 Closing Coil Replacement.........14.8 Auxiliary Switch Replacement...14.9 Motor Replacement..................14.10 “Y” Relay Replacement.............

SECTION 15−−−−Renewal Parts15.1 Ordering Instructions.................


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List of Illustrations

Figure Page

1 Front view of PowerVac® breaker with front cover.................... 62 Rating interference plate........................................................... 63 Front view of PowerVac breaker without front cover................ 84 Manual charging........................................................................ 95 Gag plate installation................................................................. 106 Operating rod assembly............................................................107 Contact gap...............................................................................118 Close coil plunger gap...............................................................129 Trip coil plunger gap..................................................................1210 Control switches .......................................................................1311 Sample operating speed graphs................................................1912 Contact gap adjustment............................................................ 2013 Spring discharge interlock .........................................................2414 Toggle linkage positions of the ML-18 mechanism...................2515 Schematic of ML-18 mechanism...............................................2716 Typical wiring diagram for ML-18 mechanism........................... 2917 PowerVac® breaker left-front view ............................................3018 PowerVac® breaker right-rear view............................................3019 Trip coil and linkage...................................................................3120 Close coil linkage.......................................................................3221 Bottom view of the ML-18 mechanism.....................................3322 Negative interlock.....................................................................34

23 Wipe spring compression.......................................................... 34

Table

1 Control Device and Voltage...............2 M easurements .................................3 Adjustments......................................

THESE INSTRUCTIONS ARE INTENDED FOR USE BY QUALIFIED PERSONNEL FOR INSTRUCTION AND MAIN TENA

REPRODUCTION IN W HOLE OR IN PART IS NOT PERMITTED W ITHOUT THE EXPRESS PERM ISSION OF GENERAL


6/78

PowerVac® Vacuum Circuit Breaker

with ML-20 Mechanism

SECTION 1—Introduction This manual provides the information needed by the user toproperly install, operate and maintain the ML-20 PowerVac® Breaker.

The PowerVac® vacuum breaker is a horizontal drawoutinterrupting element for use in metalclad switchgear to provideprotection and control of electrical apparatus and power systems. To the extent required applicable ANSI, IEEE and NEMA Standardsare met. No such assurances are given with respect to local

codes and ordinances, as they vary greatly.

1.1—SafetyEach user must maintain a safety program for the protection ofpersonnel, as well as other equipment, from the potential hazardsassociated with electrical equipment.

The following requirements are intended to augment the user'ssafety program, but NOT supplant the user's responsibility fordevising a complete safety program. The following basic industrypracticed safety requirements are applicable to all major electricalequipment such as switchgear or switchboards. GE neithercondones nor assumes any responsibility for practices whichdeviate from the following:

1. ALL CONDUCTORS MUST BE ASSUMED TO BE ENERGIZEDUNLESS THEIR POTENTIAL HAS BEEN MEASURED ASGROUND AND ADEQUATE CAPACITY GROUNDINGASSEMBLIES HAVE BEEN APPLIED TO PREVENTENERGIZING. Many accidents have been caused byunplanned energization from non-recognized back feeds,

equipment malfunctions, and from a wide variety of sources.

2. It is strongly recommended that all equipment be completelyde-energized, verified to be “dead”, then grounded withadequate capacity grounding assemblies prior to anymaintenance. The grounding cable assemblies must be ableto withstand energizing fault levels so that protectiveequipment may clear the circuit safely. Additional discussionon this concept is covered in Chapter 20 of ANSI/NFPA 70B,Electrical Equipment Maintenance.

3. Although interlocks to reduce some of the risks are provided,the individual's actions while performing service ormaintenance are essential to prevent accidents. Each person'sknowledge; mental awareness; and planned and executedactions often determine if an accident will occur. The mostimportant method of avoiding accidents is for all associatedpersonnel to carefully apply a thorough under-standing of thespecific equipment from the viewpoints of its purpose its

Instruction books, actual devices and app

maintenance practices such as OSHA pubElectric Safety Code (ANSI C2), National National Fire Protection Association (NFPEquipment Maintenance must be closelyDuring actual work, supervision should auconformance.

1.2—MaintenanceExcellent maintenance is essential for relelectrical equipment. Maintenance progr

the specific application, well planned andwith both industry experience and manufrecommendations. Local environment min such programs, including such variabletemperatures, extreme moisture, numbeatmosphere or major insect problems andabusive condition of the application. Oneactivities, sometimes neglected, involvescontrol devices. These monitored conditiosecondary circuits, sometimes initiating eaction such as opening or closing circuit b

vital role of these devices, it is important program be followed. As was outlined abthe interval between periodic checks will environment, the type of device and the

It is the GE recommendation that, until thenough experience to select a test intervindividual requirements, all significant calan interval of one to two years.

To accomplish this, some devices can betest sets. Specific calibration instructions typically are provided by supplied instruct

Instruction books supplied by manufacturthat would normally require service or mauseful life of the equipment. However, thpossible part that could under adverse enMaintenance personnel must be alert to of the supplied switchgear, taking actionsit to serviceable status.

Industry publications of recommended msuch as ANSI/NFPA 70B, Electrical Equipshould be carefully studied and applied inplanned maintenance.

Some users may require additional assistplanning and performance of maintenanc

d i h d k i


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SECTION 2—Description

2.1—General This section contains a description of the PowerVac® vacuum

circuit breaker. It also describes the functions of the electricaland mechanical systems.

2.2—Summary Description The PowerVac®vacuum circuit breaker uses sealed vacuumpower interrupters to establish and interrupt a primary circuit.Primary connections to the associated metalclad switchgear aremade by horizontal bars and disconnect fingers, electrically andmechanically connected to the vacuum interrupters. Moldedinterrupter supports, one per phase on a three-phase circuit

breaker, provide mountings for the primary bars, interrupters,current transfer fingers, and heat dissipation fins (where used). The operating mechanism provides direct motion at each phaselocation in order to move the movable contact of the vacuuminterrupters from an open position to a spring-loaded closedposition and then back to the open position on command.

The ML-20 mechanism is of the stored-egear motor to charge a closing spring. Du

the energy stored in the closing spring is vacuum interrupter contacts, compress tload the contacts, charge the opening spbearing and other friction forces, The enewipe springs and opening springs will opeopening operation.

Closing and opening operations are contrmetalclad switchgear or remote relaying.provided by manual close and trip button The closing spring may be manually char

slow-closing the primary contacts is availoperate at the ac or dc voltage indicated nameplate.

Mechanical and electrical interlocks are pdescribed in para 4.2, Interlocks

SECTION 3—Receiving, Handling and Storage

3.1—ReceivingA. Equipment Packages Every package leaving the factory is plainly marked with the casenumber, requisition number, and customer’s order number. If theequipment has been split for shipment, the section numbers ofthe equipment enclosed in each shipping package are identified.

NOTE: To avoid loss of any parts when unpacking, the contents

of each container should be carefully checked against the packinglist before discarding the packing material.

Contents of each shipping package are listed on the MasterPacking List. In addition, this list includes the number of theshipping crate in which miscellaneous parts needed to install andoperate equipment (such as hardware, contact lubricant, touch-uppaint, breaker closing devices, etc.) are located. Normally, suchdevices are packed in a cardboard carton.

B. Inspecting for Damage All equipment leaving the factory is carefully inspected and

packed by personnel experienced in the proper handling andpacking of electrical equipment. Upon receipt of any equipment,immediately perform a visual inspection to ascertain if anydamage has been sustained in shipping or if there are any looseparts.

C. Filing a Claim If any damage is evident, or indication of rough handling is

3.2—HandlingWhen lifting the breaker, use of the specrecommended. If it is necessary to lift thefour 1/2 inch diameter hooks rated at leasLifting holes are provided in the four cornmembers. (See figure 2) Use a spreader to prevent slings from contacting the inte

3.3—StorageIt is recommended that the breaker be pu

permanent location. If this is not possibleprecautions must be taken to assure prop

1. The breaker should be protected agpreferably by storing it in a warm drytemperature such as 40° - 100°F. Cmetalclad switchgear should be storwhen power is available and the heaprevent condensation.

2. The breaker should be stored in a clecorrosive gases or fumes; particular should be taken to protect the equipcement dust, as this combination is psites and has a very corrosive effect

3. Rollers, latches, etc., of the operatbe coated with 0282A2048P009 grusting.


8/78

SECTION 4—Features

4.1—Safety Precautions This circuit breaker uses powerful springs for energy storage.

WARNING: DO NOT WORK ON THE INTERRUPTERS OR

THE MECHANISM UNLESS THE CIRCUIT BREAKER IS IN THE“OPEN” POSITION AND BOTH THE CLOSING AND OPENINGSPRINGS ARE EITHER DISCHARGED OR GAGGED AND ALLELECTRICAL POWER IS REMOVED.

These precautions are required to prevent accidentaloperation. Anyone working on the circuit breaker should be

familiar with the contents of this instruction book.

Figure 1 Front view of PowerVac breakerwith front cover

1. Front cover 6. Manual charge lever2. Cover mounting bolts 7. Counter3. Manual trip button 8. Spring charge indication4. Manual close button 9. Closing spring gag access

5. Nameplate 10. Open/Close indicator

The circuit breaker has been shipped in the CLOSED position.After removing packing material, open the breaker by pushingin firmly on the manual trip button (3, Figure 1), while keepinghands away from moving parts, and verify that the operationcounter advances one count.

4.2—InterlocksEach PowerVac® vacuum circuit breake

following interlocks:

4.2.1 Rating Interference Plat This interlock (1, Figure 2) permits onlymatching continuous current, voltage abe inserted into a metalclad compartm

Figure 2 Rating interf

1. Rating interference plate2. Lifting locations (3/4” dia. hole

4.2.2 Closing Spring Interlock This racking-track operated interlock (4racking into or out of the metalclad comthat has the closing spring charged. Thaccomplished by a roller on the right simechanism which contacts the racking

discharges the closing spring, unless th“DISCONNECT/TEST” position or the “Cthe metalclad compartment. This interCL/MS switch in the motor circuit to prcharging of the closing spring when ththe “DISCONNECT/TEST” and “CONNEmetalclad compartment.

1

10

6

7

2

4

8

3

2

5

9


9/78

4.2.3 Negative Interlock The function of this racking-track operated interlock (5, Figure17) is to remove the trip latch from the trip roller therebypreventing a closing operation. The interlock also opens theLCS switch in the closing circuit thereby removing the close

circuit power. The negative trip interlock is functional whilethe breaker is being moved between the“DISCONNECT/TEST” and “CONNECT” position and uponwithdrawal from the metalclad compartment.

4.2.4 Positive Interlock Bar This interlock will prevent the racking of a closed breaker intoor out of a metalclad compartment. A linkage connected tothe cross shaft extends a détente angle (3, Figure 17) outthrough the left side of the mechanism frame when the

breaker contacts are in the closed posithe “CONNECT” or “DISCONNECT/TESTmetalclad the détente angle locks into to prevent access to the hex section of

4.2.5 Closing Spring Gag Inte The interlock is provided to prevent a bgagged closing spring from entering a function is accomplished by projecting out of the left front side of the mechanspring is gagged. This angle will interfemechanism and block entry into the mClosing Spring Gag Access Door is ope


10/78

SECTION 5—Operation

5.1—General The PowerVac® vacuum circuit breaker uses sealed vacuum

power interrupters to establish and interrupt a primary circuit.Primary connections to the associated metalclad switchgearare made by horizontal bars and disconnect fingers, electricallyand mechanically connected to the vacuum interrupters.Molded interrupter supports, one per phase on a three-phasecircuit breaker, provide mountings for the primary bars,interrupters, current transfer fingers, and heat dissipation fins(where used). The operating mechanism provides directmotion at each phase location in order to move the lowercontact of the vacuum interrupters from an open position to a

spring-loaded closed position and then back to the openposition on command.

The ML-20 mechanism (Figure 15) is of the stored-energytype and uses a gearmotor to charge a closing spring. Duringa closing operation, the energy stored in the closing spring isused to close the vacuum interrupter contacts, compress thewipe springs which load the contacts, charge the openingspring, and overcome bearing and other friction forces, Theenergy then stored in the wipe springs and opening spring will

open the contacts during an opening operation.

Closing and opening operations are controlled electrically bythe metalclad switchgear or remote relaying. Mechanicalcontrol is provided by manual close and trip buttons on thecircuit breaker. The closing spring may be manually charged,and a method for slow-closing the primary contacts isavailable. The mechanism will operate at the ac or dc voltageindicated on the circuit breaker nameplate.

5.2—Close Spring ChargingFigure 15 shows a front view of the ML-20 in a schematicform. The primary contacts are open and the closing spring ischarged. The closing spring charging system consists of aclosing spring (1, view B) mounted on the left side of thebreaker and the electrical charging system mounted on theright side of the breaker. Both components are fastened tothe cam shaft (2, view B). A manual charging system (3, viewA) is provided so that the mechanism can be slow closed andthe closing spring can be charged without electrical controlpower.

Spring charging is accomplished electrically by a rotatingeccentric on the output shaft of the gear motor driving pivotedcharging arms (4, view C) which oscillate about the centerlineof a ratchet wheel (5, view C). A driving pawl (6, view C),mounted within the charging arms, oscillates with thecharging arms. Starting from its rear-most position, as the

that three missing teeth adjacent to the

motor overspin will not drive the ratchepreventing damage to the system.

When the spring is completely chargedretained in that position by the close lato close the circuit breaker.

The closing coil cannot be electrically eclosing spring is completely charged. Tby the 52/CHG switch in the closing ci

The manual charging system (3, view Acam shaft where a one-way clutch (7, manual handle, provides rotation of thepumping of the handle advances the raholding pawl prevents counter-rotationreturning for another stroke. Approximstrokes of the manual handle are requspring-charging operation. When the sp(9, Figure 3) shows “CHARGED”, MANBE DISCONTINUED TO AVOID MECHA

Figure 3 Front view of Powwithout front c

1. Upper interrupt connection 8. Co2. Interrupter support 9. Sp3. Operating rod 10. M4. Racking arm 11. M

13

9

6

97

5

4


11/78

the linkage to rise until the prop (11, view D) can slip underthe close roller (10, view D) and hold the linkage in place. Asthe linkage moves, the output crank (12, view D) rotates thecross shaft (13, view D) which in turn rotates the phase bellcranks and compresses the two opening springs (15, view E)

on poles 1 and 3, this closes the vacuum interrupters, andcompresses the three wipe springs (16, view E) on each pole. The rotation of the cross shaft (13, view D) also changes theauxiliary switch (7, view D) position. The position flag on thefront panel will then indicate “CLOSED”. After the breaker isclosed, the charging motor is again energized and the closingspring is charged as described under “CLOSE SPRINGCHARGING”. Spring charging is possible when the breaker isin the closed position because the linkage is held in place bythe prop.

5.4—Opening Operation (refer to Figure 15)By either energizing the trip solenoid or depressing themanual trip button (23, view B), the trip latch (19, view D) isrotated, permitting the linkage to collapse and the vacuum

interrupter contacts to open under thesprings (16, view E) and opening sprinend of the opening stroke, the center passembly hits a stop block on the framand rebound. Rotation of the cross sha

the open position operates the auxiliarwhich opens the trip coil circuit. If the crecharged, the linkage will be reset andplace on the trip roller, ready for anothe

5.5—Trip-free Operation The linkage is mechanically trip free inclosing stroke. Electrically energizing thwill, after the auxiliary switch contacts the trip latch and permit the circuit brea

The linkage will reset as in a normal opclosing spring will recharge as describeCHARGING.

SECTION 6—Electric Control circuitA typical PowerVac® circuit breaker ML-20 mechanism wiring

diagram is shown in Figure 16. Check the wiring diagramsupplied with the actual circuit breaker for its wiring.

The close spring-charging motor circuit is established throughthe CL/M S (close latch monitor switch) switch if the closelatch is reset the SM/LS (spring motor limit switch) if theclosing spring is discharged and the IL/MS (Negative InterlockMonitoring Switch). When the closing spring is charged, theSM/LS interrupts the circuit.

The close coil circuit is established through two normally

closed 52Y relay contacts, and the latch-checking switch LCS,if the trip latch is reset. An auxiliary switch contact 52b is alsoin series with the close coil and closes when the breaker is

open and opens when the breaker is c

operation, cam rotation closes the SM/52Y relay to be energized; opening its coil circuit and sealing itself in through to the close signal. This seal-in action psustained close command as the closeremoved to drop out the Y relay, and recircuit, thereby providing an anti-pump

Circuit breaker mounted auxiliary switcthe control circuit are bought out for cofunctions. The metalclad equipment moperated stationary auxiliary switch for(3, 6 or 10 stages are available).

SECTION 7—Mechanical Checking and Slow Closing

7.1—Visual InspectionVisually inspect the circuit breaker for any signs of damage or

loose hardware.

7.2—Closing Spring ChargingManually charge the breaker closing spring using the charginghandle provided (1, Figure 4). The closing spring is charged bya ratcheting mechanism that advances by one ratchet tooth ata time. When the spring is fully charged and the spring load isheld by the closing latch the spring indicator (3 Figure 1) will


12/78

Figure 5 Gag plate installation

1 Closing spring gag plate2 Manual charging lever

7.3—Closing Spring Gag Insert the closing spring gag plate (1, Figure 5) by opening the

closing spring gag hole cover and inserting the tip of the gagplate between the end of the spring and the spring guide andengaging the détentes on the gag plate into the slots in theclosing spring guide. Note that when the closing spring guideis exposed for gagging, an interference angle is exposed onthe left side of the breaker (1, Figure 17). With the closingspring in the gagged position, this angle will provide

interference preventing use of the lift tbreaker element. No attempt should bmade to alter, modify or otherwise masafety feature. With the gag plate in pomanual close button. This action will pa

closing spring and also partially close thcontacts. Do not energize the secondatime.

7.4—Slow Closing To manually slow close the breaker coclosing spring gag, as described aboveclose button (11, Figure 3). Then put thhandle on the manual charge lever andand down. The breaker will be fully clo

charge indicator shows “CHARGED”.

CAUTION: WITH THE GAG PLA

BREAKER CLOSED, AND OPENING SPBREAKER CAN BE TRIPPED AT FULL

7.5—Gag Plate Removal To remove the gag plate, the closing scharged. If the spring charge indicator “CHARGED” in the window, manually c

it does. Lift up and push in on the gag pdétentes on the gag plate from the sloguide. While holding the gag plate up, opening. Close the gag hole cover. Forbreaker by depressing the manual “CLOdepress the manual “TRIP” button. All sremoved from the breaker.

2

1

8

7

6

5

4

3

1


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SECTION 8—Dimensional Checks

With the breaker closed and the gag plate installed, performthe following dimensional checks.

8.1—Primary Contact ErosionIn the closed position, the erosion marker (1, Figure 6) belowthe bus bar is aligned with a reference mark on theinterrupter’s movable stem. As contact erosion occurs, theerosion mark will move upward away from the erosionpointer. When the seribed band on the interrupter’s movablestem is completely above the top surface of the pointer, 1/8inch erosion has occurred and the interrupter should bereplaced.

8.2—ML-20 Wipe Spring CompressionWith the breaker closed and the closing spring gagged,measure with a feeler gauge and record the distance betweenthe bellville washer and the trunion between the bell crankarms.

8.3—Contact Gap The method of measuring the contact gap is as follows: With

the breaker in the open position, the closing springs charged,and the closing spring gag plate installed, apply a piece ofmasking tape to the surface of the operating rod insulator asshown in Figure 7. Using a reference block, make a mark on

the tape near the top on all three polesput a reference mark on the tape to ide

tape is applied. Remove the closing spthe breaker. Using the same proceduretape. This new mark will be near the bthe breaker, remove the tapes and re-asurface. Measure the distance betweeA caliper will give an accurate reading

Dimension G: The gaps must be betwemaximum at the center pole and 0.595outer poles. It is not necessary that all

typically adjusted breaker will have mocenter pole than on the outside poles.

The close coil and trip coil plunger gapmade in the operating mechanism whithe bottom. To accommodate these chshould be turned on its right side restinblocks. DO NOT use the portable break

CAUTION: DO NOT ALLOW ANY

CONTACT WITH THE INTERLOCK RO THE RIGHT SIDE OF THE MECHANISM


14/78

8.4—Close Coil Plunger Gap The close coil plunger gap is shown in Figure 8. With theclosing spring discharged, operate the plunger to make certainthat the plunger moves freely over its full stroke in the coil. Tocheck the closing coil plunger gap the breaker should be open

and the closing spring charged and gagged. Depress the closeplunger button until resistance is felt. The gap between theplunger button and the coil housing should be as follows:

Figure 8 Close coil plunger gap

8.5—Trip Coil Plunger Gap The trip coil plunger gap is shown in Fibreaker in the open position and the clcharged position, make certain that theshaft move freely over the full plunger

coil plunger gap adjustment, the breakthe closing spring discharged. Dimensplunger button and the coil housing shand 0.25 inch. This dimension is obtainplunger button is depressed until resistbreaker is equipped with an optional sesame procedure.

Figure 9 Trip coil pl

8.6—Control Switch Adjust The breaker is to be in the open positioclosing springs discharged. This resultsplungers being in the depressed positiochecked are shown in Figure 10 On th


15/78

Figure 10 Control switches


16/78

SECTION 9—Electrical ChecksElectrical checking consists of electrical breaker operationprimary and secondary wiring high-potential testing (ifrequired), primary circuit resistance (if required). Interrupterhigh-potential testing, and insulation resistance to ground.

9.1—Electrical Operation To check the electrical operation, attach a secondary testcoupler to the circuit breaker connector. Check the controlvoltage on the nameplate and close and open the breakerseveral times.

CAUTION: REPEATED OPERATIONS AT A RATE EXCEED-

ING TWO PER MINUTE MAY CAUSE CHARGING MOTOROVERHEATING AND FAILURE.

9.2—High-Potential TestIf high potential tests to check the integrity of the primaryinsulation is required, the AC high potential test describedbelow is strongly recommended. DC high potential testing isnot recommended. The following procedure must be adheredto.

CAUTION: IF DC HIGH POTENTIAL TESTING IS REQUIRED,

THE DC HIGH POTENTIAL M ACHINE MUST NOT PRODUCEPEAK VOLTAGES EXCEEDING 50 KV.

NOTE: Always recheck with an AC tester if initial results are

questionable.

9.2.1 Primary Circuit The breaker should be hipotted in the closed breaker mode.An AC hipot machine capable of producing the test voltagesshown below may be used to hipot the breaker phase tophase and phase to ground.

BREAKER VOLTAGE AC TEST VOLTAGE

27.0 kV 45 kV

The machine should be connected with its output potential atzero and the voltage increased at 500 volts per second to thetest voltage and that voltage maintained for 60 seconds. Thevoltage should then be returned to zero and the test leadsremoved and the breaker discharged to ground. Do notexceed the test voltage indicated.

If the test should experience a failure, STOPSTOPSTOPSTOP, turn off the test

machine from this wire to ground. Incre1125 volts (rms) 60 Hz and maintain fothe voltage to zero and remove the hipcircuit. Remove the wire connecting thpins and reconnect the motor leads.

9.3—Primary Circuit ResistaA resistance check of the primary circuwith the breaker closed. Use a low resinstrument rated 100 amperes which m The 100 ampere reading should be 25 600/1200 or 2000 amp. Breaker, when

upper and lower primary bars on the bdisconnect fingers. Do not connect direfingers as errors may occur due to fing

9.4—Vacuum Interrupter In

NOTE: Use of a DC hipot is not reco

used for quick field checks only. Alwtester if initial results are questionable.vacuum interrupter integrity test,

surface) of the vacuum interrupters shany contaminates with a non-linting wiper. This is critical: the entire extcompletely free of all dirt, debris, dust,

CAUTION: X-RADIATION WILL B

ABNORMALLY HIGH VOLTAGE IS APOF ELECTRODES IN A VACUUM. INCREASE AS VOLTAGE INCREASES SEPARATION DECREASES. ONLY ADJ USTED CIRCUIT BREAKER.

DURING A HIGH POTENTIAL OR A TEST, ANY X-RADIATION WHICH MAYNOT BE HAZARDOUS AT A DISTAPOTENTIAL TESTING, IF THE TEST ISRECOMMENDED VOLTAGE AND WITCIRCUIT BREAKER GAP.

DO NOT APPLY VOLTAGE THAT IS

RECOM MENDED VALUE. DO NOT RATION THAT IS LESS THAN THE RPOSITION BREAKER CONTACT GAP.

The vacuum integrity test is performedpotential tester. A vacuum integrity tesrequired to insure that no loss of vacuutest of the vacuum interrupter will dete


17/78

ground of the test machine or by applying a grounded cable tothe phase bus bars.

If a failure of a vacuum bottle should incur during the integritytest, the test procedure should be reviewed and the pole

piece cleaned. Failure rates for vacuum bottles is 0.0007 perfield unit.

Note the voltage level at failure on the first test; then performa retest on the phase pole piece. If the pole piece passes theretest, the vacuum bottle is acceptable - STOPSTOPSTOPSTOP. If the test failsagain but at a higher voltage level than was observed in thefirst test. Clean the pole piece and retest. If a failure of theintegrity test occurs a third time, consider the vacuum bottleto have lost vacuum and replace the complete pole piece asdescribed under Repair of Interrupter Assembly.

CAUTION: MANY DC HIGH POTENTIAL MACHINES ARE

HALFWAVE RECTIFIERS. THIS TYPE OF HIPOT TESTERMUST NOTNOTNOTNOT BE USED TO TEST VACUUM INTERRUPTERS. THE CAPACITANCE OF THE POWERVAC BOTTLES IS VERYLOW AND THE LEAKAGE IN THE RECTIFIER AND ITS DCVOLTAGE MEASURING EQUIPMENT IS SUCH THAT THEPULSE FROM THE HALFWAVE RECTIFIER MAY BE IN THENEIGHBORHOOD OF 120 kV WHEN THE METER IS

ACTUALLY READING 40 kV. IN THIS CASE, SOME PER-FECTLY GOOD BOTTLES CAN SHOW A RELATIVELY HIGHLEAKAGE CURRENT SINCE IT IS THE PEAK VOLTAGE OF 120kv THAT IS PRODUCING ERRONEOUS BOTTLE LEAKAGECURRENT. IN ADDITION, ABNORMAL X-RADIATION WILLBE PRODUCED.

Although a AC hi-potential test is recommended for checkingthe vacuum integrity, a DC hi-potential test can also beconducted on the vacuum interrupters at 50 kV and held for 10

seconds with the restrictions noted as follows:

No attempt should be made to try to coof one vacuum interrupter with anothecondition of any interrupter to low valucurrent. There is no significant correlatpotential voltage is removed, discharge

that may be retained.

Acceptable AC high potential machinesHipotronics MoHipotronics Mo J ames G. Biddle CaPhoenix Mo

Acceptable DC high potential machinesHipotronics MoHipotronics Mo

9.5—Insulation Tests The primary circuit insulation on the brphase to phase and phase to ground uother suitable megohmeter.

Since definite limits cannot be given fovalues, a record should be kept of the as well as temperature and humidity reshould be used to detect any weakenin

one check period to the next. Generallyor exceed 10,000 megohms.

To measure the breaker secondary circresistance, disconnect the motor leadsconnecting together all secondary disc#24, the ground pin. The measuremenconnecting a 500 Volt megohmeter fro


18/78

SECTION 10—Checking and Installing Breakers

CAUTION: IF THE COMPARTMENT SECONDARY CON-

TROL CIRCUITS ARE ENERGIZED, THE FOLLOWING

PROCEDURE SHOULD BE FOLLOWED TO PREVENTARCING AND BURNING OF THE MOTOR CIRCUIT PINS IN THE SECONDARY CONTACT BLOCKS: EITHER CHARGE THECLOSING SPRING MANUALLY, OR PUSH IN AND HOLD THEMANUAL CLOSE BUTTON TO OPEN THE MOTOR CIRCUIT, THEN PULL DOWN THE HANDLE AND EXTEND THEBREAKER SECONDARY CONTROL CONTACT BLOCK TOFIRMLY ENGAGE WITH ITS MATING SECONDARY CONTROLCONTACT BLOCK IN THE COMPARTMENT. RELEASECLOSE BUTTON TO ACTIVATE SPRING CHARGING MOTOR.

Verify that spacing between the lower inside edges of thebreaker roller track in the metalclad compartment is 29.807”min. to 29.857” max. Check that the breaker is OPEN and thatthe closing spring is DISCHARGED. Install the PowerVac® circuit breaker into the DISCONNECT/TEST position in themetalclad compartment.

CAUTION: IF CONTROL POWER IS AVAILABLE, CLOSE

THE CIRCUIT BREAKER USING THE CONTROL SWITCH ON

THE COMPARTMENT DOOR. THIS OPERATION WILLCHECK THE ADJUSTMENT OF THE 52/LCS SWITCH. IF THEBREAKER WILL NOT CLOSE ELECTRICALLY, RECHECK THE52/LCS ADJ USTMENT. IF CONTROL POWER IS NOT AVAIL-ABLE, PUSH THE MANUAL CLOSE BUTTON ANDRECHARGE THE CLOSING SPRING MANUALLY. SPRINGCHARGING WILL OCCUR AUTOMATICALLY IF CONTROLPOWER IS CONNECTED.

With the breaker in the CLOSED conditthe racking crank. The racking crank shPOSITIVE INTERLOCK. Trip the breaker

crank and rack the breaker toward the spring discharge interlock will dischargduring the first five turns, usually betweif the closing spring is charged. The cobreaker should remain open. (If adjustmMECHANICAL ADJ USTMENTS sectionthe breaker into the CONNECTED positclosing spring. If secondary control powclosing spring will charge automaticallybreaker is in the OPEN condition.

Rack the breaker from the CONNECTEDISCONNECT position. During the first discharge interlock should discharge ththe breaker contacts should remain OPrequired see MECHANICAL ADJ USTM16.8.)


19/78

SECTION 11—Maintenance

WARNING: BEFORE ANY MAINTENANCE WORK IS

PERFORMED, MAKE CERTAIN THAT ALL CONTROL

CIRCUITS ARE DE-ENERGIZED AND THAT THE BREAKER ISREMOVED FROM THE METALCLAD UNIT. DO NOT WORKON THE BREAKER OR MECHANISM WHILE IT IS IN THECLOSED POSITION WITHOUT TAKING PRE- CAUTIONS TOPREVENT ACCIDENTAL TRIPPING. DO NOT WORK ON THEBREAKER WHILE THE CLOSING SPRING IS CHARGEDUNLESS IT IS SECURED IN THAT POSITION BY THECLOSING-SPRING GAG.

11.1—GeneralPowerVac® circuit breakers have been designed to be asmaintenance-free as practicable. They include features suchas sealed vacuum interrupters and long-life synthetic greaseswhich contribute to many years of trouble-free performancewith a minimum amount of maintenance.

11.1.1 Interrupter The interrupter used in this breaker is a reliable, cleaninterrupting element. Since the contacts are contained in a

vacuum chamber, they remain clean and require nomaintenance at any time. The metallic vapors eroded from thecontact surfaces during high current interruption remain in thechamber and are deposited on metal shields thus insuring ahigh dielectric value of the vacuum and the walls of theinterrupter.

11.1.2 Trouble ReportingAlthough all reputable manufacturers design their products toperform satisfactorily with a minimum of problems, the IEEESwitchgear Committee, an organization of both users andmanufacturers, recognize the need for a common troublereporting format. A reproducible copy of this form is includedinside the rear cover of this book and is recommended for usewith any manufacturer’s circuit breakers.

The intent is for each maintenance organization to keepspecific problem files with this information documented.If the problem is serious or repetitive, a summary should besent to the appropriate manufacturer for action. The level ofdetail included on the form is considered very desirable sothat the manufacturer’s investigator may more thoroughlyunderstand and solve the reported problem.

11.2—Service Conditions The frequency of required maintenance depends on

Salt sprayChanges in temperature that prod

Conductive and/or abrasive dustDamaging chemicals and fumesVibration or mechanical shockHigh relative humidity (90%) Temperature extremes (below –3

11.3—Fault Interruptions The erosion rate of the primary contacinterrupters is very low for normal loadHowever, fault current interruptions at

rating may result in appreciable contacfault interruptions it is necessary to perbased on the number of interruptions. interruptions the following should be p

1. Contact erosion ch2. Wipe and gap chec3. Vacuum interrupte

11.4—Contact ErosionCheck in the breaker-closed condition pCONTACT EROSION section 8.1. When.125 inch, the interrupter should be rep

11.5—Transfer Finger WearWith the breaker open, examine the mprojecting below the transfer fingers (1off the lubricant in order to see the me The finger locations should present a b

without copper appearance at more thcopper is visible at more than one locasilver plating is torn, the interrupter assreplaced. Re-lubricate with 0282A2048

11.6—MechanismCheck all items covered in INSTALLATItighten hardware as required. Lubricateunder LUBRICATION.

11.7—Primary Insulation PaUsing dry, non-linting cloth or industriaaccessible insulation surfaces on the inand operating rod insulators. In servicecontamination is heavy or external flasduring interrupter high-potential testingi bli h d


20/78

11.8—LubricationProper lubrication is important for maintaining reliable circuitbreaker performance. The ML-20 mechanism uses bearingswhich have a synthetic lining in some locations. Thesebearings do not require lubrication to maintain low friction, but

lubrication does not harm them and oiling lightly isrecommended. Sleeve bearings are used in some linkagelocations and needle or roller bearings are used for low frictionon trip shaft and close shaft.

Bearings are lubricated during factory assembly with greaseand oil, but all lubricants have a tendency to deteriorate withage. Providing a fresh lubricant supply at periodic intervals isessential to proper breaker operation, especially wherefrequent operation may have forced lubricant out of the

bearing surfaces. Apply a few drops of light synthetic machineoil such as Mobile 1 at each bearing. Apply a coat of0282A2048P009 grease on the four corners of the closingspring guide where it enters inside the spring.

Metal-to-metal contact surfaces should be cleaned andlubricated with 0282A2048P009 grease to provide cleanlinessand prevent oxidation.

Electrical primary contact surfaces also require periodic

lubrication to inhibit oxidation and minimize friction. At eachinspection and maintenance interval, do the following:

1. Wipe clean and coat lightly with grease(0282A2048P009) all silvered primary contact surfacessuch as the movable contact rod of the interrupter andthe primary disconnect fingers.

2. Clean and coat lightly with grease the pins of thesecondary disconnect coupler.

11.9—Recommended Maint The following operations should be pemaintenance check:1. Perform a visual inspection of the

loose or damaged parts.

2. Perform slow closing operation deMECHANICAL CHECKING AND SL

3. Check the erosion indicator and thdescribed under DIMENSIONAL C

4. Perform the vacuum interrupter indescribed under ELECTRICAL CHE

5. Lubricate the breaker operating munder LUBRICATION.

6. Check the electrical operation usinavailable) or the test position in th

CAUTION: REPEATED OPERATIONS

TWO PER MINUTE MAY CAUSEOVERHEATING AND SUBSEQUENT M

7. Examine the movable contact rod interrupter. With the breaker openthe rod and examine the silver surhave a burnished appearance withthrough the silver. If copper is visiblocation per pole, or if the silver plainterrupter assembly should be repmovable contact rod with 0282A20

8. If desired, perform the additional ePrimary and Secondary High PotenResistance). See ELECTRICAL CH

Nominal Charge Motor Close Coil Trip CoilControl

Voltage Part No. Range Part No. Range

Part No.

(5 cycle)

Part No.

(3 cycle)

48 VDC 0177C5050G009 36-56 0209B8103G008 38-56 0209B8104G001 0209B8104G001

125 VDC 0177C5050G007 90-140 0209B8103G009 100-140 0209B8104G002 0209B8104G007

250 VDC 0177C5050G008 180 280 0209B8103G010 200 280 0209B8104G003 0209B8104G0


21/78

SECTION 12—Timing

Timing and speed checks are optional and also depend on thelevel of maintenance performed. Generally these tests are not

required for normal maintenance. If a new mechanism hasbeen installed or extensive repair, replacement or majordisassembly has been performed, it is recommended thatthese tests be performed.

To determine contact velocity, a travel recorder and or anoscillograph are required. Optional, travel recorder linkage canbe obtained through your local GE Sales Office by orderingpart number 0144D1235G002. A typical travel trace andinterpretation are shown in Figure 11.

Timing may be checked by monitoring control circuit voltageand using no more than six volts DC and one ampere throughthe vacuum interrupter contact to indicate closed or opencondition. Typical time ranges vary with coil voltage, butnominal values are:

Initiation of trip signal to contact parting5 Cycle Breaker 32-45Milliseconds2 Milliseconds Maximum Pole Spread

Initiation of close signal to contact 45-75 Milliseconds (DC Cont

35-65 Milliseconds (AC Contr2 Milliseconds maximum

Trip-free operation maybe checked by close and trip signal, and a minimum rebe checked by tripping a charged breamaintaining a close signal.

Instantaneous re-close time* 85-140 M

*Time from application of trip signal re-close.


22/78

SECTION 13—Opening and Closing Speed

The opening speed is modified by moving the spring adjustingnuts on the opening spring assemblies. A change in opening

speed affects the closing speed. Reference Figure 12.

The operating speeds for a 5 cycle bre

OperationOperationOperationOperation Feet Per SecoFeet Per SecoFeet Per SecoFeet Per Seco

Open 4.3 - 5.6

Close 2.6 – 3.9


23/78

SECTION 14—Repair and Replacement

14.1—General The following information covers in detail the proper method

of removing various parts of the breaker in order to make anynecessary repairs. This section includes only those repairs thatcan be made at the installation site on parts of the breakerthat are most subject to damage.

Important: Upon completion of any kind of repair work, allinterrupter and mechanism adjustments must be checked.

Refer as needed to sections on mechanical and electricaladjustments.

14.2—Replacement of Interrupter

AssembliesInterrupters are supplied in complete interrupter assemblieswhich include the vacuum interrupter mounted in theinterrupter support, the primary studs, and disconnect fingers.

CAUTION: DO NOT ATTEMPT TO REMOVE OR REINSERT

THE VACUUM INTERRUPTER IN THE INTERRUPTER

SUPPORT ASSEMBLY. SPECIAL TOOLS AVAILABLE AT THEFACTORY ARE REQUIRED.

1. Close the breaker and remove the coupling clamp, andclamp screws(8, 9, Figure 6). Hold hex projection (6,Figure 8) at the bottom of the operating rod insulator witha 1 inch wrench and loosen the adjacent lock nut with a3/4 inch wrench. Screw down the lock nut and theoperating rod insulator until clear of interrupter rod.Remove the four bolts holding the pole assembly to themechanism and remove the old pole assembly.

2. Set the new pole assembly in place and install the fourmounting bolts. Set the pole assembly so that thedistance between the primary studs and the studs on theadjacent pole is ten (10) inches center line to center line.

3. Screw the operating rod insulator up to mate with thebase of the interrupter rod. Install coupling clamp. Tightencoupling clamp capscrews, then loosen them 1-2 turns.

a. With continuity indicator across the contacts, back offthe operating rod until the contacts separate,(continuity indicator off).

b. Advance operating rod until contacts touch,( ti it i di t )

e. Check contact wipe - must be

all three phases before measunecessary that all three poles measurement as long as all thspecified limits.

f. Check contact gap - must be 0Adjust if needed per CONTACin MECHANICAL ADJUSTMEN

4. If a new interrupter assembly is inadjust the wipe indicator (2, Figurereference arm (11, Figure 6) to lin

5. Perform the VACUUM INTERRUPTas described in ELECTRICAL CHEC

WARNING: PRIMARY DISCONNECT

CHECKED WHEN THE SWITCHGEAR

14.3—Primary Disconnect F The primary disconnect finger assembby removing two roll pins which hold thprimary studs. Finger contact surfaces 0282A2048P009 lubricant.

14.4—MechanismPin Retaining Rings - These rings are wML-20 mechanism to retain pins. Theyremoved with a pair of standard pliers.

recommended. To remove, slowly squpulling. To install, position in the pin groinstallation ears closed leaving no morebetween ears. Retaining rings can be oGE Sales Office by ordering part numbe

14.5—Control SwitchesControl switches may be removed frombrackets by disconnecting the wires anmounting hardware. When replacing th

the correct type normally open or normReinstall, wire, and adjust per DIMENSCONTROL SWITCH ADJ USTMENT.

14.6—Trip Coil Replacemen TOOLS REQUIRED5/16” All h


24/78

Perform the operation in the following sequence:

1. Charge closing spring and install gag plate.2. Depress the close and then the trip buttons.3. Pump the manual close handle 3 - 4 times.4. With the 5/16” Allen wrench, remove the pivot bolt

(10, Figure 21) on the closing spring (1, Figure 21).5. Remove the closing spring.6. Disconnect the trip linkage tension spring.7. Loosen the interlock bracket (11, Figure 21).8. Remove the 4 bolts from the coil bracket leaving the two

bolts nearest the front of the breaker in place in themechanism frame.

9. Cut coil leads and remove the coil and armature.

To install the new coil, reverse the above procedure and

connect leads with insulated butt connectors. See TRIP COILPLUNGER in MECHANICAL ADJUSTMENTS section forsetting the stroke of the armature. Apply Loctite to thethreads of the pivot bolt (10, Figure 21) when it is replaced.Charge the breaker and electrically close and trip it to makecertain it has been reassembled correctly.

14.7—Closing Coil ReplacementDisconnect the close linkage tension spring then remove the

retaining ring from the close linkage pivot pin (17, Figure 21)and disconnect the linkage. Remove the closing coil andhousing (6, Figure 21). Cut the leads to the closing coil andremove the coil. Reassemble the coil and housing witharmature and butt-splice the new coil into the wiring harness.Reassemble linkage and spring. Readjust the closing coilarmature travel in accordance with instructions inMECHANICAL ADJ USTMENTS section under CLOSE COILPLUNGER.

14.8—Auxiliary Switch ReplacementWith the breaker open and the closing spring discharged,remove retaining clip from auxiliary switch shaft. Observe andmake of the

direction of the index mark on the end position of the operating link in relationRemove mounting hardware securing mechanism plate. Slide auxiliary switchoperating link. Before removing any wterminals, make sure they are properlyterminal numbers to assure proper plaRemove wires.

To install new switch, attach leads theswitch shaft in operating link with indexabove. Reverse above procedure to co

14.9—Motor ReplacementWith the breaker open and the closing

remove auxiliary switch as described adisconnect leads. Move switch towardenough to clear motor and tie there temmotor leads. Remove the long bolt andmotor to the mechanism mid-plate. Rehead cap screws securing the motor toplate using a 5/16” Allen socket and a 2Disengage the motor output shaft fromarms and withdraw motor.

To install the new motor, reverse the a

14.10—“Y” Relay ReplacemBefore removing the “Y” relay, make suwith terminal locations. Next, disconnethe two fasteners securing the “Y” relamounting bracket to the mechanism rerelay and bracket. Remove fasteners smounting bracket.

Reverse the above procedure to instal


25/78

SECTION 15—Renewal PartsIt is recommended that sufficient renewal parts be carried instock to enable the prompt replacement of any worn, brokenor damaged parts. A stock of such parts minimizes serviceinterruptions caused by breakdowns, and saves time andexpense. When continuous operation is a primaryconsideration, more renewal parts should be carried, theamount depending upon the severity of the service and thetime required to secure replacements.

Renewal parts which are furnished may not be identical to theoriginal parts, but they will be interchangeable.

Renewal Part numbers are available frooffice.

15.1—Ordering Instructions1. Always specify the complete nam

breaker and mechanism.

2. Specify the quantity, catalog numbnumber (if listed), and description and the parts bulletin number.

3. Standard hardware, such as screwetc., should be purchased locally.

SECTION 16—Mechanical Adjustments16.1—General The ML-20 Mechanism has been designed for extendedintervals between maintenance. In most cases only the wipeand gap adjustments will require re-setting throughout the lifeof the circuit breaker.

16.2—Wipe Adjustment

Wipe is the additional compression of a preloaded spring,used to apply force to the vacuum interrupter contacts andto provide opening kick-off force.

The contact wipe adjustment should always be made beforemaking the contact gap adjustment.

ML-20 The wipe measurement is made with the breakerclosed and the closing spring gagged. Measure with a feelergauge the distance between the bellville washer and the

trunion between the bell cranks arms. Adjustment is notrequired if wipe is more than 0.100 inch. After adjustment thewipe should be 0.160 – 0.185 inch.

To adjust the primary contact wipe, close the breaker andproceed as follows:

1. Loosen, but do not remove, the two capscrews (9, Figure8) holding the interrupter clamp.

2. Check that the interrupter clamp is loose. A light pry at

the clamp half-junction may be required to loosen thewedging action of the clamp.

3. Hold the hexagon projection (6, Figure 6) at the bottomof the operating rod insulator (1 inch wrench) and loosenthe adjacent locknut (3/4 inch wrench). (Refer to 4,Figure 6). Adjust by rotating the operating rod insulator.The thread is 1/213andeachturnwill give about0 076

the wipe springs and forcing relativthe clamp interface.

After adjustment, remeasure the wipe settings are within the required limits, tcontact closing relationship between th

16.3—Contact Gap Adjustm The gap adjustment refers to the sepathe primary contacts within the vacuumattempting to measure or set the gap athe wipe settings are within acceptablethe wipe settings will affect the gap se

1. Adjust the center phases first. The0.595 – 0.655. The adjustment of taffects the center phase measurein the open position and the closinlocate the gap adjusting nuts on th

connected to the outer phase bellLoosen the jam nut on both rods. bolt on the center phase VI stop (F

2. Advance or retard the adjusting nuway you want to change the gap. same amount.

3. Lock the jam nuts after setting theOperate the breaker a few times afollowing the procedure described

CHECKS, item 3.

4. Readjust the center phase VI stopadjusting screw for no clearance bspring rod striker with the breaker

After adjustment of the left and right pcenter phase The center phase should


26/78

Reference DIMENSIONAL CHECKS for breaker position andspring status.

16.5—Close Coil Plunger To adjust the close coil plunger gap, Figure 8, lift locktab away

from adjusting nut. Turn adjusting nut until close latch actuatormakes contact with close latch while maintaining the correctplunger dimension. Bend locktab to secure adjusting nut.

Reference dimensional checks for required dimension andbreaker position and spring status.

16.6—Close Spring Discharge Interlock THIS INTERLOCK IS FACTORY SET AND SHOULD NOT BEROUTINELY ADJ USTED IN THE FIELD. The adjustment for

this interlock is as follows. (See Figure 13).

CAUTION: THIS IS A SAFETY FEATURENOT A ROUTINE MAINTENANCE ITEM

Figure 13 Spring Discharge Interlock

The breaker should be open with the c

1. Back off 1/4 inch linkage adjusting

2. While holding roller at 0.995 inch dadjusting screw to just touch inter

3. Check that spring discharges with minimum dimension.

4. Close latch must reset as indicate

16.7—Negative Interlock THIS INTERLOCK IS FACTORY-SET ANROUTINELY ADJ USTED IN THE FIELD

is adjusted with the breaker closed anddischarged. (See Figure 23).

1. Hold roller at 0.670 inch from mecAdjust linkage so the striker just mproperly adjusted trip linkage.

2. Lock in place with 1/4 inch hardwa

3. Check that breaker trips with rolle

dimension.

4. Check that linkage moves freely.


27/78

Figure 14 Toggle linkage positions of the ML-18 mechanism(Viewed from right side) Continued on next page

(A) Breaker open - spring discharged

1. Output crank2. J ackshaft3. Trip latch4. Trip roller5. Closing roller

6. Trip link7a. Closing toggle7b. Closing toggle8. Prop9. Closing cam

10. Prop spring11. Linkage return spring


28/78

Figure 14 Continued

(C) Breaker closed - spring discharged


29/78

Figure 15 Schematic of ML-20 mechanism

1. Close spring 12. Output crank2. Cam shaft 13. Cross shaft3. Manual charge 14. Bell cranks

4. Charging arms 15. Opening springs5. Ratchet wheel 16. Wipe springs6. Driving pawl 17. Auxiliary switch7. One-way clutch 18. Trip solenoid8. Close latch 19. Trip latch9. Close cam 20. Over-travel stop

10. Close roller 21. Latch check switch11. Prop 22. Gear motor

23. Manual trip button

(Continued on next page)


30/78

Figure 15 Continued

Partial View A Partial View B

Partial View C Partial View D

Partial View D


31/78

Figure 16 Typical wiring diagram for ML-20 mechanism


32/78

Figure 17 PowerVac® breaker left-front view

1. Gag interlock angle2. Track rollers3. Positive interlock bar4. Closing spring discharge roller5. Negative interlock roller6. Rating interference plate7. Front cover8. Racking engagement lever9. Secondary coupler

7

8

2

7

8

2

3

5

1


33/78

Figure 19 Trip coil and linkage

1. Trip coil2. Closing spring3. Trip linkage adjusting rod and nut

3 12


34/78

Figure 20 Close coil linkage

1. Close linkage adjusting nut2. Close linkage adjusting rod

1 2 3

Fi 21 B tt i f ML 18 h i


35/78

Figure 21 Bottom view of ML-18 mechanism

5

1. Closing spring 10. Pivot bolt2. Opening springs 11. Interlock bracket3. Auxiliary switch 12. SM/LS motor control switch4. Spring charging motor 13. LCS latch checking switch

5. Trip coil 14. CL/MS close latch monitor switch6. Close coil 15. Stationary auxiliary switch operato7. Ratchet wheel 16. Close latch adjustment screw8. Closing cam on -0, -1 & -2 breakers only9. 52Y relay 17. Close linkage pivot

3 4 6

1

11

10

9

2

12

8 16 13


36/78

*Install rivet in aligned holes with interlock roller, set at .670 and striker making contact with a

CAUTION: This is a safety feature not a routine maintenance ite

Figure 22 Negative interlock

A change in the setting of the close latch stop bolt willaffect the adjustment of the spring discharge interlock

TABLE 2 MEASUREMENTS


37/78

TABLE 2 MEASUREMENTS

ITEM BREAKER CL. SPRING OP. SPRING MEASUREME

CONTACTWIPE

OPENCLOSED

CHARGEDCHARGED

DISCHARGEDCHARGED

MEASURED BETWEENWASHER AND TRU

CONTACTGAP OPENCLOSED CHARGEDCHARGED DISCHARGEDCHARGED MEASURE THE TRAVEOPERATING ROD INS

CONTACTEROSION CLOSED DISCHARGED CHARGED INDICATION ON

TRIPCOIL CLOSED DISCHARGED CHARGED

MEASURE BETWEEN BUTTON AND COIL H

CLOSECOIL OPEN CHARGED DISCHARGED

MEASURE BETWEEN BUTTON AND COIL H

CONTROLSWITCHES OPEN DISCHARGED DISCHARGED

DEPENDS ON SWITSEE SECTION

TIMING SEE SECTION

CONTACTSPEEDS SEE SECTION

TABLE 3 ADJ USTMENTS

ITEM BREAKER CL. SPRING OP. SPRING MEASUREMECONTACT

WIPE CLOSED CHARGED CHARGEDADJ UST OPERATING

OBTAIN REQUIRED D

CONTACTGAP OPEN DISCHARGED DISCHARGED

ADVANCE OR RETAADJ USTING NUTS TO

CONTACTEROSION CLOSED DISCHARGED CHARGED

ALIGN REFERENCE TBAND ON INTERRUPT

NEW UNITS ON

TRIPCOIL CLOSED DISCHARGED CHARGED

TURN ADJ USTING NUTREQUIRED DIMEN

CLOSECOIL OPEN CHARGED DISCHARGED

TURN ADJ USTING NUTREQUIRED DIMEN

CONTROLSWITCHES OPEN DISCHARGED DISCHARGED

ADJ UST MOUNTING BOBTAIN REQUIRED D

OVER- TRAVEL

STOPOPEN DISCHARGED DISCHARGED SEE SECTION 16.3, IT

ADJ USTMEN

INDEX


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INDEX

A

Adjustments (Table 3) 35Auxiliary Switch Replacement 22

C

Close Coil Plunger 24Close Coil Plunger Gap 12, 24Close Latch Stop Bolt 24, 34Close Spring Charging 9Closing Coil Replacement 22Closing Operation 8Closing Spring Charging 8Closing Spring Discharge Interlock 24

Closing Spring Gag 10Closing Spring Gag Interlock 23Contact Erosion 17Contact Gap 11Contact Gap Adjustment 23Control Circuit 9Control Switch Adjustment 12

D

Description 5Dimensional Checks 11

Close Coil Plunger Gap 12Close Coil Linkage 32Contact Gap 11Control Switch Adjustment 12Primary Contact Erosion 11Spring Wipe 11 Trip Coil Plunger Gap 12

E

Electrical Checks 14Electrical Operation 14High-Potential Test 14Insulation Test 15Primary Circuit 14Primary Circuit Resistance 14Secondary Circuit 14Interrupter Integrity Test 14

Electrical Operation 14

F Fault Interruptions 17Features 6

G

Gag Plate Removal 10

I

Install Front Cover 6Installation 16

Insulation Tests 15Interlock Functional Check 15Interlocks 6, 7

Spring Discharge Interlock 6Closing Spring Gag Interlock 7Negative Interlock Roller 7Positive Interlock Bar 7Rating Interference Plate 6

Introduction 4

L Lubrication 18

M

Maintenance 4, 17Contact Erosion 17Fault Interruptions 17General 17Lubrication 18Mechanism 17PowerVac Interrupter 17Primary Insulation Parts 17Service Conditions 17 Transfer Finger Wear 17

Measurements (Table 2) 35Mechanical Adjustments

Close Coil Plunger 24Close Latch Stop Bolt 24Contact Gap 23Negative Interlock 24

Spring Discharge Interlock 24 Trip Coil Plunger 24Wipe Adjustment 23

Mechanical Checking and SlowClosing 9, 10

Mechanism 17, 21, 33Motor Replacement 22

N

Negative Interlock 24, 34Negative Interlock Roller 7, 24

O

Opening and Closing Speed 19, 20Opening Operation 9Operation 8, 9

Primary Circuit Primary ContacPrimary Discon

Primary Insulat

R

Rating InterfereReceiving 5RecommendedRenewal Parts

Ordering InsRepair and Rep

“Y” Relay 22

Auxiliary SwiClosing Coil Control SwitcInterrupter AMotor 22

Primary Discon Trip Coil 21

S

Safety 4

Safety PrecautSecondary CircService ConditSlow Closing 9Spring DischarSpring Wipe 2Storage 5

T

Timing 19

Instantaneou Trip-Free Op

Transfer Finge Trip Coil & Link Trip Coil Plung Trip Coil Plunge Trip Coil Repla Trip-Free Oper Trouble Report Table 2 Measu

Table 3 Adjustm

V

Vacuum InterruVisual Inspectio

W

U


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FAILURE REPORTING FORM FOR POWER CIRCUIT BREAK

Check all appropriate blocks and provide information indicated. For major trouble provide additional informatio

page supplemented with additional pages if necessary.User Ident

EQUIPMENT: Station____________________________ of Breaker_Equipment Nameplate Mfgr._______________________________Type_______________ Serial #___

Information kV_______Inter Amps/MVA___________________Continuous Amps_________

Breaker Background: Shipped________, Installed________, Maintained_________, Modernized_______,(Mo/Yr) (Mo/Yr) (Mo/Yr) (Mo/Day/Yr

Operational Counter Reading _______________________________________________________________Location: ! Indoor ! Outdoor Enclosure: ! Non-metal Clad, ! Metalclad, ! GISInterrupter: ! Air Blast, ! Air Magnetic, ! Oil, ! SF6, ! Vacuum, Other__________________

ENVIRONMENT: General: ! Industrial, ! Urban, ! Suburban, ! Rural, ! Sea Coast, ! Above 3300', ! High C

Other______________________________________________________________________Weather Conditions: ! Dry, ! Rain, ! Lightning in Area, ! Snow, ! Fog, ! Freezing Rain, ! Fro

Temp. Trend ! Rising, ! Falling, ! Steady, ! Extreme Cold, Temperature_____ ° F,

Wind ! Calm, ! Light, ! Strong-Steady, ! Strong-GustyExternal Mechanical Stresses Involved: ! Normal, ! Earthquake, ! Wind, ! Abnormal Terminal Load

Other_________________________________________________________________________________Nominal System voltage __________________________

TROUBLE:

When Discovered: ! Installation, ! In Service, ! Maintenance, ! Test, Other ___________________Breaker Mode at Time of Trouble: ! De-energized, ! Closed, ! Open, ! Tripping, ! Closing, ! Recl

! Fault Interruption, ! Load Switching, ! Line SwitchingBreaker Response at Time of Trouble: ! Not Called Upon to Operate, ! Performed at Intended, ! Unsa

! Failed to OperateSubsystem in Trouble: ! External Insulation to Ground, ! Internal Insulation to Ground, ! Insulating ! Isolating Contact, ! Bushing, ! Interrupter, ! Seals-Gaskets, ! Air System, ! SF6 System, ! C.T

! Resistor Sw or Aux. Int., ! Voltage Grading Device, ! Line Terminals, ! Compressor, ! Heater, ! ! Wiring, ! Operating Mechanism, ! Mechanical Linkage, ! Other _____________________________

______________________________________________________________________________________

State Specifically What Failed (With Instr. Book Ref.): __________________________________________

______________________________________________________________________________________

Has it occurred before on this type of breaker? ! No, ! Yes, How many times____________________

State How Problem was Corrected: _________________________________________________________

______________________________________________________________________________________

POSSIBLE CAUSE: ! Design/Manufacture, ! Shipping, ! Storage, ! Installation, ! Instructions, ! Mai! Wear/Aging, ! Animal/Birds, ! Other, ! Not Obvious

Comments and Suggestions: _____________________________________________________________

______________________________________________________________________________________

______________________________________________________________________________________EFFECT:

Breaker Down Time: ! No Interruption, ! 30 Min. or Less, ! 1 Hr, ! 2 Hr, ! 6 Hr, ! 12 Hr, ! 24 Hr, ORepair Time: ! Less than 30 Min ! 1 Hr ! 2 Hr ! 6 Hr ! 1 Day ! 2 Days ! 3 Days ! 1 Week O

ADDITIONAL INFORMATION REQUIRED FOR ANALYSIS OF MAJO


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QSYSTEM RELATED FAILURE

(USE ADDITIONAL PAGES AS NECESSARY)

(1) Single line station diagram showing involved breakers

(2) Operation and timing sequence (including all alarms) of this and related breakersfrom last time that conditions were definitely normal

(3) Line conditions before, during, and after failure

Intentionally Left Blank


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These instructions do not purport to cover all details or variations in equipmprovide for every possible contingency to be met in connection with inoperation or maintenance. Should further information be desired or should

problems arise which are not covered sufficiently for the purchaser's purpmatter should be referred to the General Electric Company.

g


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Voltage Circuit Breaker

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