Answering Today’s Power Challenges 13-3 HMT / Zig-Zag 13

13Power QualityAnswering Today’s Power ChallengesJefferson Electric is continually updating its product lineto remain on the forefront of transformer technology.Electrical harmonics have become a real world problemto many of our customers, especially those with highenergy usage and very stable voltage needs. For thesecustomers, we have a solution.This section of our catalog contains our products linedeveloped to mitigate harmonics.13-313-7HMT / Zig-ZagHarmonic Suppression SystemsFor further information, contact an Application Engineer at800-892-3755, technical services@jeffersonelectric.comWhy Your Existing TransformerMay Be InadequateTraditional transformers were designed to handle thepurely linear electrical loads created by standard lightingand motors. The currents drawn by these loads aresinusoidal in shape, as is the waveshape of the supplyvoltage. When loads are linear and balanced, as in atypical three-phase system, the neutral current flowis zero. This is because the three-phase currents are120 degrees out of phase with each other and cancelin the neutral. The sinusoidal current waveshape is thefoundation for wire-size calculations, determining how tobalance loads to reduce neutral currents, and reducing thesize of neutral conductors to reduce material costs.The Phenomenon of Odd HarmonicsElectronic equipment today is powered by SMSPs (switchmode power supplies) that convert AC current to DCcurrent. SMSPs use rectifiers and capacitors drawingcurrent in sharps bursts which distorts the sinusoidalwaveform. It is now non-linear.Non-linear loads, are rich in odd harmonics (3, 5, 7,etc.), which are multiples of the fundamental 60 Hertzfrequency. The major components of harmonic currentsin switched mode power supplies are the third and fifthharmonics. The 3rd harmonic current (180Hz) due to thedesign of the 3-phase system, is additive in the neutraland can result in a neutral current twice the phase current,even in a balanced system.How Harmonics Affect TransformersWhen odd-harmonic currents are present, winding lossesincrease. The I2R, conductor losses, are higher becauseharmonics increase the current. Stray losses in windingsalso increase losses due to additional eddy currentscirculating within the conductors. The combination ofthese additional losses generate excess heat in thetransformer coils. Transformer insulation systems aredesigned to accommodate temperature increases due tonormal stray losses. However, when required to carry nonlinear loads, the heat generated may exceed the designedrating, reducing the life of the transformer and creating thepossibility of premature failure.De-rating is Not the AnswerDe-rating a traditional linear transformer to compensatefor heat build-up requires higher installation costs andprovide poor energy efficiency due to increased corelosses.13-1

13-2Power QualityK-Factor Type of LoadHarmonic SuppressionK-1 Resistance heatingIncandescent lightingMotorsTransformers Control DistributionInstead of filtering third harmonic currents from theline after they are generated, our patented HarmonicsSuppression System (HSS ) works at the source toprevent the generation of these currents.K-4 WeldersInduction heatersHID lightingFluorescent lightingSolid state controlsK-13 TelecommunicationsequipmentBranch circuits in classrooms and healthcare facilitiesK-20 Mainframe computersVariable speed drivesBranch circuits with exclusive loads of data processingequipmentHarmonic MitigationHarmonic Mitigating Transformers (HMT/Zig-Zag) andK-rate transformers accommodate the flow of the thirdharmonic current. They dissipate the extra current as heat(I2R loses) in the transformer.Because they are so common to our product line, weincluded K-rated transformers (Chapter 3, Non-LinearTransformers) in our standard catalog.The Harmonic Mitigating Transformer (HMT / Zig-Zag) lineis defined in on the following pages.The HSS is extremely reliable, is UL certified, and is fullycompliant with the National Electrical Code. It is the onlyharmonic mitigation system that “prevents” the formationof third harmonic currents throughout the electricaldistribution system, rather than just “accommodating”these currents after they are formed. It is the onlyharmonic mitigation system that reduces wasted energyand has an energy payback. It is clearly the technologyof choice for solving third harmonic current problemsin electrical systems that power multiple computer andelectronic loads.SysteMax is a stand alone third harmonic suppressionfilter that installs on the neutral of an existing distributiontransformer. It is sized to the transformer (15 to 1,000 kVA).Enclosure type is UL/NEMA Type 1, steel with ANSI–61gray paint.While SysteMax can be installed on any transformer,Harmonics Limited recommends it be placed on at least ahigh efficiency DOE compliant transformer. If the existingtransformer does not meet DOE-2016 specifications thenreplacement with a TransMax is advised.TransMax is harmonic suppression technologyincorporated in a single enclosure with a high efficiencytransformer. The basic transformer has a 480V primary,208Y/120V secondary, with copper or aluminum windings,115 C rise and electrostatic shielding. Standard sizesrange from 30 kVA to 500 kVA. More information can befound in on page 13-7.GenMax addresses issues arising when multiplegenerators of different pitch are paralleled. Each pitch hasa slight variation in the voltage waveform which can causeexcessive 3rd harmonic current to flow in the system.Jefferson Electric Dry-Type Transformers jeffersonelectric.com 800-892-3755

Harmonic Mitigating (Zig-Zag)13-3HMT Three-Phase Zig-Zag TransformersThe HMT (Harmonic Mitigating Transformer) is a threephase transformer with 0 or -30 displacement betweenthe primary and the secondary.An HMT is used to reduce current harmonics on theprimary side of a transformer and voltage distortion onthe secondary. A single HMT reduces the flow of triplenharmonics, 3rd, 9th, 15th, 21st, etc into the transformerprimary. Used together on the same power line a 0 and-30 HMT will also reduce the 5th and 7th harmonics.These transformers are designed to reduce voltagedistortion when powering non-linear loads.Applicationsn For use in environments with non-linear loads suchas computers, printers and communication equipmentwhere stable load and operation is necessaryn Medical facilities including hospitalsn Data centersn Office buildingsStandardsn Built in accordance with NEMA, ANSI, UL and CSAstandardsn UL and CSA Listedn SchoolsOptions and AccessoriesSpecificationsConsult factory for more informationn K-13 standardn DOE-2016 efficiencyn NEMA3R enclosuren 3 phase, 60 Hzn 480V primaryn 50 Hzn Other sizes, voltages and temperature rises availablen Copper windingsn K-4 and K-20n Dual electrostatic shieldsn Zig-Zag secondary design voltage 208Y/120Vn 115ºC, 80ºC temperature risen 0º and -30º phase shiftsApprovalsn 15 – 1,500 kVA rangen Aluminum windingsn 150ºC temperature risen 220ºC insulation classn Heat-cured ASA-61 gray powder coating finishn Electrostatic shieldn Cores of high quality electrical steel

13-4Power Quality – Harmonic Mitigation (Zig-Zag)Enclosure FiguresModel Numbers DefinedFigure 24424-TXXY-ABC3 Phase VentilatedNon-Linear Zig-ZagAll models with electrostatic shieldEnclosure TypeDOE-20169Mounting BracketsPart NumberDescriptionMax Unit Wgt (lbs)223-7008-030For 15 kVA units, 150 C rise250223-7008-075For 16 to 50 kVA units, 150 C rise750kVA Rating / Primary208240240480480Specials*Not assigned208600Part NumberkVAPrimary LugQtySecondary Lug15#14 - 22#2/0 - 624PT-2017-LUG25#14 - 22250MCM - e Rise150 C Rise0115 C Rise180 C Rise8Qty4PT-2008-LUG37.5#14 - 22350MCM - 624PT-2009-LUG50#2/0 - 62600MCM - 624PT-2018-LUG*75#2/0 - 62600MCM - 64* Must be ordered, not included on stock /277123456789Lugs4PT-2007-LUGkVA Rating / rd HarmonicK 4, Zig-Zag, -30 degrees4K 13, Zig-Zag, -30 degrees5K 20, Zig-Zag, -30 degrees6K 4, Zig-Zag, 0 degrees7K 13, Zig-Zag, 0 degrees8K 20, Zig-Zag, 0 degrees9* Suffix defined incrementallyJefferson Electric Dry-Type Transformers jeffersonelectric.com 800-892-3755

Power Quality – Harmonic Mitigation (Zig-Zag)Three-Phase Harmonic Mitigation (Zig-Zag) Transformers–DOE CompliantK-13 Electrostatic Shields 150 C Temperature Rise Aluminum Windings NEMA3R EnclosuresTaps: 2@2.5% FCAN, 2@2.5% FBCN480V Delta — 208Y/120VkVACatalog NumberEnclosureFigureHeight 2424242424252832384246526072Width (B)inches222527293335354852Depth 4242742Est ShipWgtMounting 0MThree-Phase Harmonic Mitigation (Zig-Zag) Transformers–C802 CompliantK-13 Electrostatic Shields 150 C Temperature Rise Aluminum Windings NEMA3R EnclosuresTaps: 2@2.5% FCAN, 2@2.5% FBCN600V Delta — /an/an/an/an/an/aSee website for additional kVA, copper windings and temperature options.Housing dimensions subject to change without notice. Consult website or factory where dimensions are critical.For further information, contact an Application Engineer at 800-892-3755, technical T600GT600GT600GT600GT600G13-5

13-6Power Quality – Harmonic Mitigation (Zig-Zag)Wiring DiagramsT480M Wiring Diagram & ConnectionsT600G Wiring Diagram & ConnectionsWiring DiagramWiring DiagramPrimary: 480 Volts DeltaSecondary: 208Y/120 VoltsPrimary: 600 Volts DeltaSecondary: 208Y/120 nnectionsOn Each CoilJumper Taps ToPrimary LinesConnect ToPrimary VoltsOn Each CoilJumper Taps ToPrimary LinesConnect To5041H1, H2, H36301H1, H2, H36152H1, H2, H3Primary Volts4922H1, H2, H34803H1, H2, H36003H1, H2, H34H1, H2, H354684H1, H2, H35854565H1, H2, H3570Secondary LinesConnect ToSecondary Volts208X1, X2, X3208X1, X2, X31201 phaseBetween X0 andX1 or X2 or X31201 phaseBetween X0 andX1 or X2 or X3Secondary VoltsH1, H2, H3Secondary LinesConnect ToMore wiring diagrams can be found in catalog’s appendix, section 15.For further information, contact an Application Engineer at 800-892-3755, technical services@jeffersonelectric.comJefferson Electric Dry-Type Transformers jeffersonelectric.com 800-892-3755