Sola HS20F750B 0.750KVA 120X240-16/32 BB
Buck–BoostTransformers
Buck-Boost transformersaresmall,singlephase,drytype distributiontransformersdesignedandshippedas insulating/isolatingtransformers.Theyhaveadualvoltage primaryandadualvoltagesecondary.Thesetransformers canbeconnected forawiderange ofvoltagecombinations. Themostcommonuseistobuck(lower)orboost (raise)
thesupplyvoltageasmallamount, usually 5to27%. Buck-boosttransformersareincompliancewithNEC Article210.9, Exception1whenfieldconnected as
anautotransformer.
Themajoradvantages ofBuck-boosttransformersaretheir lowcost, compactsizeandlightweight.Theyarealsomore efficientandcost lessthanequivalentisolationtransformers. Whenconnectedasanautotransformer,theycanhandle loadsupto20 timesthenameplaterating.Abuck-boost transformer istheidealsolutionforchanging linevoltageby smallamounts.
Whenabuck-boosthastheprimaryandsecondarywindings connected,perrecommendedinstructions,itbecomesan autotransformer.Now, onlythesecondarywindingsare transformingvoltageandcurrent.ThemajorityofthekVA
loadpassesdirectlyfromthesupplytotheload.Thisisthe
reasonbuck-boosttransformerscansupplyaloadwitha muchlargerkVAratingthanthenameplateindicates.
Lowvoltagelightingcontrolapplications
SolaHDbuck-boosttransformersaredesignedtosupply powertolow voltagelightingcircuits,controlpanels or othersystemsrequiring12, 16, 24, 32, or48 Volts.When connectedasaninsulatingtransformer(byfollowingthe wiringdiagramlocated afterthespecificationtables onthe insideofthetransformer case), thetransformer’scapacity matchesthenameplatekVA rating.
SolaHDbuck-boosttransformersarealsosuitedforlow voltagelandscape lighting.TheyareULListedforoutdoor serviceandtheircompact sizemakes themtheperfect solutionforprovidingpowertoaccentlightingapplications. ElectricalConnectiondiagramsareshownattheendof
thissection.
Usedimmersontheoutput ofthetransformerthatare designedandratedforusewithmagneticloads.Westrongly recommendcontactingthedimmermanufacturerforadvice onyourspecificlightingapplication.
CertificationsandCompliances
•Listed
-UL506
-CSAC22.2No.66
Accessories
•SurgeProtective Devices
•ActiveTracking®Filters
Threephase,buck-boostapplicationsrequiretwoorthree transformers.Checkthe“QuantityRequired”columnofthe ThreePhaseSelectionTablesfortheexactquantity.
FusingBuck-BoostTransformers
Fordeterminingthecorrect sizeofbreaker orfuseforagiven
rangeofinputoroutput ampereratings,refertoSection
450.4, oftheNationalElectricCode (NEC).
Whereanovercurrent protection deviceisrequired,the electricalconnectionsandselectiontableswillreference appropriately.
UsingtheSelectionTables
1. DetermineifyouaretryingtoBoost(raise)orBuck (lower)yourvoltage.Selectaninput/outputvoltage combinationthatcomesclosesttomatchingyour applicationfromtheappropriatesingleorthreephase chartsonthefollowingpages.
2. Moveacross yourselectedinput/outputvoltagerowto theamperageorkVAratingclosestto,butgreaterthan theratingrequiredbyyourload.
3. Readingthetopofthecolumnwillgiveyouthe catalognumberoftheexactbuck-boosttransformer youneed. SeetheSpecificationTablesonthe
nextpage.
4.Connectthetransformersaccordingtothediagram indicated.SeetheElectricalConnectionssectionatthe endofthissection.Connectiondiagramsarepacked witheachtransformer.
Selection Steps
1.InputLineVoltage
Measure thesupplyvoltagewithavoltmeter.
2.VoltageRequiredfortheLoad
Checktheloadequipmenttodetermine thevoltage
requirement.
3.kVAorAmpereRatingoftheLoad
FindeithertheloadkVAortheloadamperage requirements.Thisinformationislistedonthe nameplateoftheloadequipment.
4.Frequency
Either50 or60 Hz.The frequencyofthetransformer mustmatchthefrequencyoftheload.
5.NumberofPhases
Singleorthreephaselineandloadmustmatch.
(Atransformer cannot convertsingletothreephase.) A common applicationistomakeasinglephase connectionfromathreephasesupplybyusingone phaseofthethreephasesupplycircuit.Becarefulnot tooverloadthatphaseofthethreephasesupply.For buck-boost applications thesupplymustprovideload kVA–notjustthenameplateratingofthebuck-boost. RefertotheSelectionTablesonthefollowingpages.
