Owner's manual

- 6-
4‐Introduction
Inputpowerisappliedacrossthemotordrivenvariabletransformerwhichhasa“centertap”that
dividesthevariabletransformerintobuckingandboostingvoltageareas.Thebuck‐boosttransformeris
afixedratioisolationtransformercapableofhighamperesatlowvoltage.Theratioofthebuck‐boost
transformerisdeterminedbytheamountofvoltageneededtobuckorboosttheinputlinevoltageto
maintainthespecifiedoutputlevel.Thebuck‐boosttransformersecondaryiswiredinserieswiththe
loadandtheprimaryisconnectedacrossthevariabletransformer’s“centertap”andbrush
terminals.Dependingonwhichsideofthe“centertap”thevariabletransformerbrushispositioned,
thevariable/buck‐boosttransformersystemwilladdto(boost)orsubtractfrom(buck)theinputline
voltage.Thefurtherthevariabletransformerbrushisfromthe“centertap”themorebuckingor
boostingofvoltagewilloccur.Thekeytotheprovenreliabilityandlongtroublefreeservicelifeofa
VoltageRegulatorisinthecombinationofamotordrivenvariabletransformerwithbuck‐boost
transformertechnology.
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InputOutput
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Figure1.Singlephaseregulatorblockdiagram
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Asshowninfigure1,theonlyactivecomponentinthemainpowerpathofthevoltageregulatoris
thesecondaryofthebuck‐boosttransformer.Thisgivestheregulatortheadvantageofbeingableto
withstandsubstantialcurrentoverloads.Thevariabletransformerbrushes,whicharethemost
vulnerablecomponentinany
variabletransformersystem,arecompletelyisolatedfromoverload
conditionsbythebuck‐boosttransformer.Duetotransformerinefficiencyaboverateddesign,the
amountofcurrentthatthebuck‐boosttransformercaninduceacrosstoitsprimarywindingandinto
thevariabletransformercircuitisdramaticallydecreasedasregulatoroverload
currentincreases.
 Thecontrollermonitorstheregulator’soutputvoltageandthenusesthesefeedbacksignalsto
determinedrivecommandsforthevariabletransformermotorinterfacecircuit.Thecontrolleris
designedtoadjustthemotorizedvariabletransformertoprovidea+/‐1~2%orbetteroutputvoltage
regulationovertheentireinputvoltagerange.
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5‐FunctionsIntroduction
M Controller
Buck-Boost transformer Variable transformer