AMVACTM Vacuum Circuit Breaker with MagneticActuator Mechanism

AAMMVVAACCUniversal applications:• Medium voltage motor starting

applications• Capacitor switching• Retrofit applications to replace

existing circuit breakers in repetitive duty applications

• Mining applications where high reliability and resistance to dust and humidity are critical

AMVAC circuit breakers have beenfully tested to the most recent versions of ANSI C37.04, C37.06,and C37.09. Using "k" factor equals1 as the test criteria, the AMVAC isthe first ANSI medium voltage circuit breaker to successfully complete standard and definite purpose capacitor switching tests asdescribed in the revised standards.

Available for 5, 15, and 27 kV applications, in stationary and drawout forms, this next generationcircuit breaker offers solutions formany applications.

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AMVAC. The circuit breaker.

Although many refinements have been made throughout the 80-90 yearhistory of the medium voltage circuit breaker, there have been only four generations of circuit breaker design. Early circuit breakers were springcharged units with separate close and trip springs. These units were used forolder air-magnetic breakers. The second generation used the same mechanism modified for use with a vacuum bottle. The new generation ofcircuit breakers, such as the ADVAC breaker with a torroidal spring, weredesigned specifically for use with vacuum technology.

Each generation reflects the best technology available at the time of theirintroduction, building on the strengths of previous designs, yet adding newinnovations, marking true turning points.

Although it is well established that vacuum interrupters are capable of morethan 10,000 operations, conventional stored energy circuit breakers seldomoperate beyond 10,000 operations without teardown, re-lubrication, and/orreplacement of parts. More than 300 parts are required to perform springcharging, closing, anti-pumping and tripping functions. Conventional storedenergy breakers also place limitations on the types of control voltagesallowed. Vacuum interrupters were mounted in open moldings, making themsusceptible to dust, moisture, and corrosive atmospheres.

The AMVAC is truly the next generation in medium voltage vacuum technology. With the AMVAC, ABB is the first to combine the unique requirements of vacuum interrupter technology to a stored energy mechanism designed to exploit these capabilities. Using a flux-shiftingdevice with integral permanent magnets, the AMVAC mechanism has justone moving part. Having only open and close coils, an electronic controller,and capacitors for energy storage, the AMVAC circuit breaker mechanism iscapable of 100,000 operations. Vacuum interrupters are embedded in a pro-prietary epoxy material, achieving excellent dielectric and thermal capabilities.Eliminating mechanism operated cell switches, the AMVAC breaker packagesall auxiliary control contacts on the circuit breaker. These are just a few ofthe features that mark a departure from the conventional stored energybreaker and introduce new capabilities and benefits for the modern power systems.

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AAMMVVAACCSummary of benefits:• Simple mechanical operation• Fewer than 10 moving parts• Manual opening capability• Capable of open-close-open after loss

of control power• High reliability

Emergency manual breaking mechanism

Electronic controller

Magnetic actuator

Electrical energy storage

Sensor for switching position detection

Auxiliary contacts

The magnetic actuator,encapsulated vacuum interrupterpole assemblies, electronic controller, capacitors, and pushbutton/capacitor discharge assembly are the key componentsfor this next generation product.The magnetic actuator has a magnetic frame assembly, two identical operating coils, two rareearth magnets, and a single movingarmature. Instead of mechanicalassemblies for armature positionsensing, proximity sensors detectarmature position for the electronic controller. The rare earthmagnets are especially encapsulatedto eliminate the corrosion normallyassociated with this type ofmagnet. Evaluation confirms thatthese permanent magnets willretain 99% of their flux density forover 100 years.

Similar projections find that thecapacitors used for stored energyhave lifetimes up to 10 years.These special capacitors charge inas little as seven seconds after control power is available and areperiodically "topped off" by theelectronic controller as needed.Covers over the capacitor terminalsprevent accidental contact. Thecapacitors are discharged by aunique discharge assembly whenthe circuit breaker is moved to the"Out" position and the rackingtruck handles are moved inward tounlock the circuit breaker from thebreaker compartment.

The AMVAC circuit breaker isdesigned to provide many years oftrouble free service for the enduser.

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AMVAC. Qualities that convince.

Maintenance free vacuuminterrupter and currentcarrying parts in oneembedded assembly.

5 kV

15 kV27 kV

Innovation extends to the vacuum interrupterassembly, as well. For the first time in any vacuum circuit breaker, the interrupter and thecurrent carrying parts are completely embedded ina proprietary epoxy resin. Thermal performanceof the interrupter is improved as the epoxy resindraws heat away from hot spots for a more evenheat distribution. Moreover, the interrupter poleassembly is fully skirted so that push rod andother moving parts of the current transfer area areisolated and protected from external influences.As a result, accumulations of dust, dirt, and condensation do not increase tracking and partialdischarge as they do in non-embedded designs.

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AMVAC. Low maintenance permanent magnet technology. Instantaneous

representation ofmagnetic flux densitydistribution

Magnetic latching in alimit position.

Magnetic latching pluscurrent build up in onecoil.

Armature reaching theopposite limit position.

Following the advance of vacuum interruption in the field of medium voltagecircuit breakers in the last 20 years, a naturalteaming of technology has been achievedwith the addition of magnetic actuator technology. The requirements of one technology are optimally matched by theopportunities of the other. Magnetic actuatortechnology naturally provides the suitabletravel-time and force-travel characteristics forthe vacuum switching devices. All operatingmechanism functions are integrated in themagnetic actuator of the AMVAC circuitbreaker. The actuator is a bi-stable magnetsystem, in which armature change-of-state isaccomplished by the magnetic field of twoelectrically excited coils. The armature is heldmagnetically in the limit positions by thefields of two rare-earth permanent magnets.Switching operations are achieved by excitation of one of the two coils until theretaining force of the permanent magnets isexceeded. Even on complete failure ofauxiliary power, electrical operation is stillpossible for a period up to 200 seconds.When capacitor stored energy is no longersufficient to achieve tripping, the circuitbreaker can then be opened with the assistance of a manual trip handle.

The armature of the magnetic actuator islinked to an operating shaft connected viainsulated push rods to each of the vacuuminterrupters. The only points of lubricationfor this mechanism are at the union of thearmature to the operating shaft, the pivotpoints of the operating shaft, and the pivotpoints of the operating shaft to the pushrods. Long life synthetic lubricants areapplied during assembly to further reduce theneed for lubrication during the life of the circuit breaker. During circuit breaker rack-ing, mechanical interlocks from the rackingmechanism block the movement of the magnetic actuator armature so that the circuitcannot be closed in any racking position otherthan "Test" or "Connect".

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The electronic controller uses robust components and circuit board con-forming coatings to prolong the life of the device. The electronic con-troller will operate on AC or DC control power because it utilizes an ACto DC converter internally. Instead of selecting from a long list of con-trol power options, the user only needs to select a controller for low volt-age control power (24-60 VAC or VDC) or a controller for high voltagecontrol power (110-250 VAC or VDC). Inside these ranges, the user mayapply any value of direct current, or any value of 50 or 60 cycle alternat-ing current to achieve circuit breaker operation. The electronic controllerincorporates all capacitor charging, open/close coil switching, anti-pump-ing, interlocking, and armature position details. Self-monitoring functionsare programmed to monitor proximity sensors, the microprocessor, andother key functions with annunciation and/or circuit breaker opening pos-sible. Radio frequency and transient testing has been performed on theelectronic controller to ensure that it is resistant to such abnormal condi-tions. The electronic controller demands up to four amperes continuous,10 amperes peak during capacitor charging; only four watts of energy isneeded to maintain controller functions and capacitor full charge.

Proximity sensors provide highly reliablearmature position information to the electronic controller.

AMVAC. Circuit-breaker ofthe high tech generation.

AMVAC. Technical data.

Breaker Nominal Rated Rated Short Short Close and ImpulseType Voltage Voltage Circuit Time Latch Level

Class kV Current kA Current kA Peak (BIL) kVSym. (k=1) (2 secs.) Crest

5AMV25 5 4.76 25.0 25.0 65 605AMV31 5 4.76 31.5 31.5 82 605AMV40 5 4.76 40.0 40.0 104 60

15AMV25 15 15.00 25.0 25.0 65 9515AMV31 15 15.00 31.5 31.5 82 9515AMV40 15 15.00 40.0 40.0 104 9527AMV16 27 27.00 16.0 16.0 42 12527AMV25 27 27.00 25.0 25.0 65 125

Table 1-Short Circuit Ratings:

Rated Rated Short 1200 Ampere Continuous 2000 Ampere ContinuousVoltage Circuit Current Rating Current Rating

(kV RMS) (kA RMS) General Definite General Definite Purpose Purpose* Purpose Purpose*

4.76 25.0 400 630 400 6304.76 31.5 400 630 400 6304.76 40.0 400 - 400 -

15.00 25.0 400 630 400 63015.00 31.5 400 630 400 63015.00 40.0 400 - 400 -27.00 16.0 160 400 160 40027.00 25.0 160 400 160 400

Table 2-Capacitance Switching Ratings:

Parameter 5 kV 15 kV 27 kVMechanical operations-mechanism 100,000 100,000 100,000Mechanical operations-vacuum interrupter 30,000 30,000 30,000Operating cycles at rated current 30,000 30,000 30,000Operating cycles at short-circuit current 100 100 100Control power at rest

AMVAC. The modern circuit breaker.

1. Upper Primary Terminal

2. Vacuum Interrupter

3. Epoxy Potting Compound

4. Lower Primary Terminal

5. Flexible Connector

6. Wipe Springs

7. Insulated Pushrod

8. Jackshaft

9. Stroke Adjustment

10. Position Sensors

11. Close Coil

12. Permanent Magnets

13. Armature

14. Open Coil

15. Manual Opening Actuator

16. Mechanism Enclosure

The AMVAC is the firstvacuum circuit breakerto combine low maintenance embeddedvacuum interrupters, alow maintenance magnetic actuator, and amaintenance-free electronic controller.The result is a mediumvoltage circuit breakercapable of 100,000 operations.

AAMMVVAACCThe equipment specifications:• Interchangeable with ADVAC• Completely concealed moving parts• UL Labeling and CSA compliance• Low Power consumption• ANSI compliance at 5, 15, and 27 kV

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GeneralThe Circuit breaker shall be an ABB AMVAC or approved equal, three-pole,drawout (or stationary) type, electrically operated with stored energy magneticactuator operating mechanism. The circuit breaker is intended for use as ageneral purpose device in accordance with the latest revisions of thefollowing ANSI standards applying to 5, 15, or 27 kV applications: ANSI C37.04, C37.06, and C37.09.

Option: Definite purpose or non-standard ratings arerequired in accordance with project data sheets, and availability is confirmed in writing with the vendor.Definite purpose ratings shall be in accordance with thelatest revisions of the following ANSI standards: C37.04,C37.06, and C37.09. Circuit breakers of this same type,rating and control features shall be electrically and mechanically interchangeable.

Drawout Circuit Breaker Racking System andInterlocksThe circuit breaker shall be inserted and withdrawn bymeans of a breaker mounted racking system, whichcan be operated with the compartment door open orclosed. The racking system shall provide smoothconsistent racking, and shall secure the breakerfrom both sides of the cell in all racking positions. During racking, the breaker shallautomatically open and close cell-mountedsafety shutters to cover stationary primarycontacts when the breaker is not in the“Connected” position.

The racking system shall havethree distinct positions. Inaddition to the withdrawnposition (free movement):“Disconnected” (both primary and secondary contacts disengaged), “Test”(primary contacts disconnected andshutter closed), and “Connected” (primary andsecondary contacts engaged). Positive stops shall be provided for all three positions, with deliberate operator intervention required toenable continued insertion or withdrawal of the circuit breaker from any position. The racking system and all moving parts of the breaker-cell interface, including the secondary coupler, shutter actuator and ground contact, shall be capable of 500 complete rack-in/rack-out operations without maintenance.

It shall not be possible to insert or withdraw a closed breaker, and the breaker shall not be allowed to close within a cell unless it is in the“Connected”, “Test”, or “Disconnected” position. Electrical and mechanical blocking means shall be employed to preclude breaker contact closure in any position other than “Connected”, “Test”, or “Disconnected”. The stored energy capacitors shall be automaticallydischarged in the “Disconnected” position prior to removing the circuit breaker from the circuit breaker compartment.

ControlsOpening and closing speed shall be independent of the operator or of the control voltage within the rated control voltage range. Circuitbreaker charge, close, and trip circuits shall be electrically separated, and control voltage for each circuit shall be independently selectablefrom the full range of ANSI preferred control voltages. Manual provisions shall be provided for tripping the circuit breaker. These provisions shall be installed and easily accessible at the front of the breaker.

AMVAC. Circuit breaker specifier's guide.

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On drawout circuit breakers, a self-aligning,fully automatic secondary coupling systemshall be used to connect and disconnect allcontrol wiring during circuit breaker insertionand withdrawal. The secondary disconnectshall require no manual intervention to attainproper position when the breaker is racked tothe “Connected”, “Test”, or “Disconnected”positions. Secondary contacts shall use a corrosion inhibiting contact finish. The circuitbreaker shall include eight on-board auxiliarycontacts (four normally open "a" and fournormally closed "b") for customer use, wiredthrough the secondary disconnect. All break-er-mounted contacts shall operate in both the“Connected” and “Test” positions.

Option: Nine additional contacts (for a totalof nine normally open "a" and eight normallyclosed "b") shall be installed on the circuitbreaker and wired through the secondary disconnect, for a total of 17 on-board contacts.

The circuit breaker shall have a flag to indicate open or closed position. An indicating light will illuminate when the stored energy systemhas sufficient energy for circuit breaker change of state. During the capacitor charging function, the indicator blinks green illuminationuntil full capacitor charge when solid green illumination is provided. Capacitors shall store sufficient energy to provide and open-close-open function even after loss of control power. Capacitors shall hold their charge for up to 200 seconds after loss of control power. Aloss of control power trip function shall be user selectable.

The circuit breaker shall have a five-digit, non-resetting operation counter clearly visible from the front of the breaker. The operationcounter shall advance when the breaker opens. An electronic controller shall be provided for controlling capacitor charging, switchingcapacitor energy to the closing or opening coils, and providing the anti-pumping feature. The electronic controller shall also incorporateundervoltage and remote monitoring functions. Electronic controllers shall be universal AC/DC devices allowing either 24 - 60 VAC orVDC or 110 - 250 VAC or VDC control power flexibility. All control components shall be front-accessible for quick inspection aftereasy removal of the circuit breaker front cover. Proximity sensors shall be used to sense magnetic actuator armature position.

Option: Electronic controller shall have (instantaneous) (time delay) undervoltage function that shall cause the circuit breaker to openwhen the control power falls to a value which is 30-60% of nominal voltage.

Option: Electronic controller shall be equipped with Close Blocker and Close Locker features to electronically prevent local or remoteactuation of close function.

Current PathEach primary lead assembly shall consist of a vacuum interrupter completely embedded in an epoxy resin casting. The epoxy castingshall encapsulate not only the vacuum interrupter, but also the upper and lower current carrying parts and brush-type current transferassembly. The epoxy casting shall limit access to any moving parts, protecting them from dirt and debris. Epoxy encapsulation shall beused on all 630, 1200, or 2000 ampere circuit breakers. Connecting directly to embedded pole pads, silver-plated copper upper and lowerleads shall use tulip-type self-aligning primary disconnects. A dedicated ground contact shall be provided to engage the stationary groundcontact in the circuit breaker compartment to ground the circuit breaker in all positions from “Disconnected” through “Connected”.

Maintenance and HandlingThe magnetic actuator mechanism shall be front-accessible. No routine lubrication of the magnetic actuator shall be required. Routineinspections shall be performed with the breaker in the upright position. Interrupters shall have a contact wear indication for evaluationby contact measurement tools. Circuit breakers shall have self-contained wheels designed for easy insertion, removal and transport onflat indoor surfaces.

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ABB Inc.655 Century PointLake Mary, FL 32746 U.S.A.For sales & marketing contact your localrepresentative or:Tel: +1-407-732-2000

1-800-929-7947 Fax: +1-407-732-2161www.abb.com/mediumvoltage