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Basicallythetransformerhastwowindings,whethertheyareoverlayedoralignedinanotherfashion,ontwosidesofatoroid.

Theratiobetweentheprimaryturns(theonetobeconnectedtothemains)andthesecondaryturnsistodeterminethetransformerperformance,i.e.thisratiodeterminestheoutputvoltage.

Atrasnformersupplied,say,with100Volts,100primaryturnsand50onthesecondary,hasaturnsratioof2:1whenweconsiderthesupplyvoltage.HoweverthisratiobecomesAlittlemorecomplicatedifweconsiderseveralthingslikethetypeofwirediameteramongothers....

Ionlymodifysecondarywindings,Idon'tcareabouttheprimarybecauseifyoudosoyou'relookingforproblems,themostcommonbeingtheexageratedheatgeneratedbytheiron,onaccountoftheexcessivemagneticflux....andtheotherproblemassociatedw/AnexcessiveACcurrentintheprimary.Bothcancauseproblemsandsometimesfire,themagneticironhasitslimits,itsaturates,andthemagneticsaturationpointsupposedtocausemoreenergyhasaconsequence,theblockingandthereturn....

Icountthesecondaryturnsofthetransformer,afterIremovethebladeshittin

gthemwithahammer,whileIholdthetransformeronthepalmofmylefthandtodampthehits,andtoavoidnicksontheiron.AtthesametimeI'mpullingthebladeswithapairofneedlepointpliers.Believeme,it'snoteasy,you'llhurtyourhandsbadevenusingathickragorapad,yourhandswillbecamebruisedwiththehitsofthehammer.Itisaveryunpleasantjob,theironbladesaregluedtogetherwiththevarnishandtheyneedtobehithardtobeabletobeungluedfromeachother.WhentheyareseparatedfromeachotherYoucanseetheyhavetwoshapes,anEcomplementedbyanI.TogethertheyresembleSomethingclosetoan8,thathassquareholesinsteadofroundones,inanotherwordsThe8doesn'tlookliketwoO'ssuperimposed,itlooksmoreliketwosquares,on

eontopoftheother.Themiddleisopenandisfilledwiththewirebobbinwhichisaplasticformwiththewirewindings.Theformonwhichthebobbin(windings)iswiredhasfirsttheprimarywindingandthanthesecondary(s)windings.Thiswillconstitutethenucleousofthetransformer.Theform,beingplasticisrelativelythinandwithtimeitcracksandsometimesgetscrambled.

Ontopoftheprimaryiswoundthesecondarywinding.Anotherwaytosayitis,theSecondaryisontopoftheprimarythusbeingtheoutsidewinding.Howeverthisisnotmandatory,theoppositesometimeshappens,beingtheprimarytheonethathasmore

Turnsthanthesecondary.It'sconnectedtothemains,110Vor220Vanditneedstohaveinductanceandalsoelectricresistance.Itcouldreach100metersinlengthandConsequentlythislengthshowsreasonableresistance,severalohmsalbeitthewireHaslowresistancewhichisinadequateenoughtothehomebuilder.ThewirecouldGettangledbeingsothinasahumanhairandobviouslycreatesproblems.ThisistheReasonwhyIonlymesswiththesecondarythathasbiggerdiameterwires,ismuc

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hMoremanageablebecausetheyareshorterandlessprontogettangled.Theyarealsoheavieranddon'thaveatendencytoformloopssoundesirableforthediyers.

TurningbacktoourtransformerItakeareadingatthevoltageonthesecondary(beforethedisassembling,ofcourse)afterIconnecctittothemains.Itakeanoteofthissecondaryvoltage,say,50volts.IfwhendisassembledIfoundthatthissecondaryhas50turns,eachoneisone(1)volt.Suppose(andallthisisjustanexample)thatIwanttohave25+25voltsonthissecondary,soit'seasy...I'lltakethatwireandBendittoexactlyahalfandwindtheturnsthatwillbeTWOparallelturnsrunningtogether.Theywillbe25countsincetheturnsratioisonepervolt,andIwant25volts.Multiplying1by25,theresultwillbe25,right?So,thesamespaceonthebobbinisocuppiedbythewire,wewillnothave50turnsanymore,only25,howevertheseareDOUBLEturns,andtheendswillhaveeach25Volts,beingthespotonthebendO(zero)volts.That'sit!

Nowwrapapieceofthincardboardorheavypaperaroundthewindingyoujustmade

Andtapeitifyou'dlikeinorderforthewindingnottobecameloose....

Incaseyouwantedtoreducethevoltage,saytoonly30voltsAConthesecondary,withThesametransformerthathas50turnsand50voltsontheoutput(thistransformerhasnotbeendisassembledyet)willbemodifiedtohave30volts.AsithasOneturnpervoltIneedtounwinditandwinditback30turnstogetthe30volts.Withtwowires.....HoweverIfindoutafterthatIhavesomesparespaceleft,soI'llremovethewirethatIWiredbackandwindothertypewithalmostdoublethediameter.ThiswayI'mgettingtwiceasmanyamperesofcurrent.

WhatdoIdo?I'llthrowawaytheoriginalmagnetwirekeepingasample.I'llgooutandbuyabiggerdiameterwire.

I'llwind30turnsofthisnewwireandtheresultwillbeabiggercurrent,increasingalsoThewattageofthefinaltransformer.BeforeIhad50volts/1amp,nowI'mgetting30V/3amps,inthefirstcaseIhad50WATTS,nowI'llgetalmost90watts,providedImaintainthesameprimary.

Sometimes,however,you'llobtainthesamepower,50watts,thiswaythecurrent

willbe1,66ampswithlessvolts,30.Thisisthemostcommontohappenbutinothercasestherewillsomegaininwattage....andtheoverheattoo...hehe

Nowsupposeyouwanttodoublethewinding,youwanttohave50V+50V,butthisWholewindingisnotgoingtofittheholeintheiron,soyou'llhavetoreducethediameterofthewiretoahalf,thewholetransformerisgoingtobelessincurrentand....biggerinvoltage.50V+50Vistwiceasmuchandthecurrentwhichwas1Abeforewillnowbe0,5A+0,5A.....

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Youshouldnowunwindthewire,measurethediameterandbuythesamelengthwhichThenmustbestretchedinsideyourhouse....AgoodwaytodoitistoholdthewiretoThedoorknobsandstartwindingbackthesame5turnsNOWDOUBLE,andbendtheSamewaywedidbefore.Thebentwillbethe0voltspoint.Onemorethingonthisisyoucanwindthewireeitherclockwiseorcounterclockwise,atyourwill.

Rememberthisimportantpoint,themagnetwirecannothavetoomuchtensioninordernottobreaktheprotectiveenamel,thecopperstretchesbuttheenameldoesn't,itcracksAndcausesshortswhichcancausethetensionofthewindingstobedifferentfromoneAnother.

Othermethodofdoingthisistowindthewireinasinglerowasopposedtodoublewire....howeverthiswaycancauseproblemsbecausethefirst50turnsaregoingtotakeasmallerdiameterportionofthewinding.So,incaseyouwantthesamevoltageinbothhalvesjustdothemethodofthetwowiresDescribedbefore,thedifferencesaregoingtobeminute,perhaps100milivolts,atthemost.Incasewewanttohaveothervoltagesinthesamebobbin,forexample2-0-2

volts,taketwowiresandusethesamemethod,runthemtogetherthroughthehouseanddoTWOturnsoverthe50Vwinding,tietogetherthepointwherethetwowiresbendandsolderthemafterremovingtheenamelabout1cm...(Themagnetwiredoesn'tsolderIfyoudon'tremovetheenamel)...Breakthepointofbending,thiswillbethe0Vpoint

You'llnowhave50V+50Vand2V+2V,ifyouwantothervoltagesyoucanalwaysusethesamemethodtakinginconsiderationthespaceyouhaveinthebobbintodoso....

Rememberyou'llhavetoisolateeachdifferentvoltagewindingswithsomeformofinsulatingpaperorthincardboardandtapeit.

Thistechniquenotbeingamisteryhoweverittakesalotofworkandhurtsyourhands,....always!

TranslatedtoEnglish,checked,correctedandadaptedbyMr.JohnMateus,fromfredon,NewJersey.USAThebasictextbyDestroyerX