CA1188765A - Electrical transformer - Google Patents

Abstract

TITLE : ELECTRICAL TRANSFORMER
INVENTOR : AURELE J. BLAIN

ABSTRACT OF DISCLOSURE

An electrical transformer having a maximum frequency limit of 500 Hertz, comprising of a closed iron channel which surrounds the windings and said channel constitutes the core, and said channel and windings extend to form a square ring. Means are provided to prevent eddy current from flowing length wise in the channel. Said channel is free of lamination. To increase the efficiency of the transformer a capacitor is connected across a secondary winding producing an oscillating flux in the said channel or core that drives the channel below saturation; causing an oscillating flux in the channel that induces an opposing voltage in the primary, thereby, increasing the impedance of the primary winding.

Description

~8~7~S

BACK5ROUND OF INVEiJTION
' ~
The devlce or electrical trans~ormer, as usually referred to, can~ists of a primary and seco~dary winding which ls wound on a core; the core extends around the coil to form a closed loop to provide a low reluctance path for the magnetic flux. The primary Windlllg C0118i9tS of many turn6 of wi~e wound around the core. The secondary also consi~ts of many turns uround around the core and u~ually on top o~ the pr~ary. This type of transformer is knowm as the shell transformer. When an alternatin~ ~oltage ls applied to the primary currenk flows in the primary and this causes a magnetic flux i~ the core; the flug cuts the wires of the seeondary winding and and induces a volta~e in them. Also, the flux cuts the wires o~ the Primary and causes a counter volta~e which tends to ~ppose the voltage applied to the pri~ary and this causes the primary to have a high impedance which is very desirable. ~'7hen a load ~s applied across the secondary current flows in the secondary producing ~ flux Ylhich reduces the flux produced by the primary. This lowers the primary lmpedance and more current flo~ which increa~es the flu~ in the core.
These transformers are rated according to the number of turns in the winding and the cross sectional area of the core.
This typ~ of transformer is very well knouln~, howe~er there are several problems associated with the design and operation of the transformer. For example, wheu the size o the primary winding is increased The section of the core which surrounds the Winding will havs to be increased and this will increase the~ re~luct~nce of the core, because the reluctance of the core varies directly proportional with it~ length, that iS1 increasin~ the len~th of the core incrcases the reluct~nce of the core proportion~lly. Incrcasing the nurnber of turn~ in the primary wlndin~ will increase thc impedance of the w$nding, however, a l~nger core will be required and tnis will result in a hi~her relnctance.

7~;5 .
Since thc ef~i~cicncy Or tho transfor~ner decreases a~ the relUctanco of the core increasesl therefore9 lncrea6ina the number of turn~ in the winding and maintaining the same cros~ sectional area of the core ~ill not increase the effi~clency of the transformer much due to the increase in reluctance of the core~ Increasin~ the cross sectional area of the core will decrease the reluctance~ since the reluctance i~ directly proportional to the cross sectional area of the core.
Thi~ will increase the impedance of the primary winding and the efficiency of the transformer, however, this will increase the weight of the transformer. Al~o, to prevent eddy ' currents, currents which are induced in the core as the magnetic flux penetrates the core, the core must be made of laminated steel and sometimes the lamination becomeS looose and rattles. Another problern is the dissipation of heat When the coil is wound around the core it forms a large mass and it is difficult to cool the centre of the core. Furthnore, due to the size of the core these ~ransformers are always heavy.
To describe my invention fully it is necessary to introduce tne discoveries, which I found, relating to magnetic fields around conductors. In the followin~ the term 90 degrees, which is used to indicate the phase relations between current and volta~e in electrical circuits9 will indicate a value slightly less than 90 degrees. Sirnilarly the term one quarter cycle will mean slightly ~less than one quarter cycle. Also, the term "line Or force" will mean magnetic fields which occur in space or in air and it is also used as A term to measure the strength of ma~netic fields.
I have proven that when a conductor carrying an electric current is surrounded by iron the electroma~netic field around the conductor will exi~t and it w~ e uniform through the entire .. . .
len~th of the conductor that is surrounded by iron. Furthermore, I have proven that the magnetic field around a conductor carrying current wlll remain perpendicular to the conductor and it will not bend frorn this position to pass through iron.

Also, it is l~no~rn -that wherl two windingrs, such as the windin~ of a transformer, are iden-tic~l and if -the current flowing in the~n is opposite the magnetic fields will be opposite and oppose each other and cancel each other so that the resultant flux in the core ~ill be zero. Furtherrnore, if a current flowJing through a conductor and, for example, if the conductor forms a loop so that the conduc-tor will be parallel to each other and the space hetween -the conductors is non magnetic such as air -the current flowing through one half of the loop will be ln one direction and it will return in the other half of the loop in the opposite direction this will produce two magnetic fields around the conductor which are equal in magnitude and opposite in polarity and, therefore, they will cancel each o-ther resulting in no magnetic field. However, in the preceding example, if an iron plate of low reluctance were placed between the conductors the magnetic field would pass through the plate and they would not completely cancel each other. Also, in the precedin~ e~ample in order for the fields to cancel each other the current flowing in the conduc-tor must be in phase with the voltage. For example, if the current is in the form of a high frequency there would be inductance and capacitance and the fields would not always oppo.se each other and magnetic fields around the conductor would exist~
Furtherthermore, if a conductor, carrying electric current, forms a loop and if the loop is a circle and if in the centre or axis of the circle an iron core is place it would seem that all of the magnetic field around the conductor would be directed to the core and would pass through the core, howe~er, this is i)mPossible because as the field approaches the core it would be crowded and since like fields repel each other most of the field would be repelled so that it would not exist and o~ly some of the field would reach the core.
This same condition would exist if a large transformer winding is wound on a small core only part of th`~ field from the outer section of the winding would reach the core.

I have found that in the daai~n o~ a transformer the pri~ary wlnding i~ the ma~or factor in determi~i~g the ~ize of the coreO It is very important that the primary ~indi~g have enough reactance to oppo~e the voltage applied to it ~o that the trans~ormer will be efficiant. In a~ electric tran~former the current induced 1 the 6econd~ry ~ill produce a magnetic field which uill very nearly cancsl a proportional amou~t of the primary mag~etic ~ield. The reaS~n that a complete proportional amou~t i~ not ca~celled i8 due to.log6es in the tran6~0rmer. Al~ov if thesecondary ~ ing i6 shorted a large ~ield would exi~t that would almo6t cancel all the field produced by the primary, the rea&on it would not c~ncel it ~11 is due to lo~e~ in the tran~for~er. Fro~ the foregoing it ca~ be seen that o~ly a small core i~ required to tran~orm an electrlc current. ~owev0r, ~here mus~ be en~h glu~ in the core to produce the primary wi~ding impedance ~d tha Recoudary ~indi~g voltage.
I ha~e ~oun~ that the problems ~ith the design oi the tran~ormer that were re~erred to ~n the ~oregoing carl be improved.
In the new embodl~e~t the~i~di~g are placed in a clo~ed ~h~n~el a~d the 5ald cha~nel e~ætitut~ the core o~ the tra~rermer and Raid cha~nel extendg to ~orm a loop or a ~q~are ri~ the le~Bth of the ch~
~ creased the length Or the ~i~di~g ~ill a:L~o be increa~ed and this wll~ l~creased t~ ~agnetic ~ield pro~ortiorally.
I~ t~e ~eu o~bodi~ent kh~ ~0re i8 ~olid~ that i8 ~ there arc no lami~ation#. Thl6 can bs achiered by ~ieparati~g the loop ~ormed by the ch~nnel 80 that curr9~t6, i~duc0d ~ the core by the vary~g ~agn~ic field, ca~n~t ilo~ around through the core.

Furthermore~ b~c~luse the ~i2ldl~gs are in~ide the core and the core i~spread out ~ore the di~ pat10n of h~at, produced by the~
core, ~will ba muc~h higher. Furthermora, b~ increasirl~ the number of turn~ the cros~ l~ectional area og ~he cera can be decrea~ed more and still mai~tain the ef flcie~cy o~ the tr~or~er .
Further~ore, it i~ po~ible to decreasç the size of the core by connectl:ng a capacitor acro~6 th0 ~eco3~dary ~rindi~g.

7~5 The value o~ ~ha capaeitor ~u~t be cho~e~ ~o it will oscillate wlth the secondar r windlng ~d pxoduce a~ oscillatin~ curren'c in the wind~g.
T~e o~ci.llatln~5 curreII~t ~ill have the same frequency as that applied to ~he pri~ary ~nd it will be out o.~ pha~e arld it ~rill cau~e ~ ~oltage to be lnduGed ir~ tha pri~ary ~Rhich e~ill terld to oppo~o the curre~t ~lo~ i~ the prl~r~. ~!hi~ crea~e ths primar~ impeda~c0 greAtly, The curre~t llhic~ ~.11 flo~ 1~ the pri~ary will ba the current vhich i~ requ:lre~ to ~ustalD. o~cillatio~ ln th~3 ~3eco~dary, ~he~l ~o load i8 applied to th~ ~eco~dar~ wi~dlng.

sDr~Elx or ~5,V~
It i3 the ob~e~t o~ thi~ rsntio~ to pro~ide an improved oloctrical trans~or~er.
A rurther ob Jee~ o~ thiE~ entio~ 1~ to pro~ide an elec -trical tr~s~or~er ~vlth the wi~dl~g ellclo~ed i~ a cha~el; the channel ~ormillg a loop a~d i~crea~i~g the lellgth o~ the loop and mal~taining the ~am~ le~g~h of Gol~.ducte~rg it ~qill bs pos~ible to decrease the Cha~el cro~ ection periDIater thil3 ~rill decrea~e the reluctance of the channel aIad i~ i8 then possible to decrea a the thickness of the chanrlel, maki~y; the tran~ormar lighter.
~ furtller ob jeclt o~ thi.~ in~e~tlon i3 to pro~ide a tra~sfor~er :in lrhich the cor3 eom ?r~:~es of a chan~el ~orml~g a loop a~d the oha~el may ~:0118i8t oi a tube or a ~qua~e closed eha~el.
A further ob~ect oi:` thi~ in~ention 1~ to pro~ida a tran6~0r-mer ~hi~h hag improved heat di8~31 pat~g qualitie~ because tha channel provideg more ~urface to diss~ pate hoat .
A ~urthor ob~oct of thi~3 in~entio~ i.8 to pro~ide a tra~sSormer in ~hich the cha~nal a:an be bullt a~ part of a Irame for Rome other apparatu~.
A Purthar obJact o~ thi~i in~enl;ion i6 to pro~lde a tran~3 ~ormer which doe~ ~ot have a laminated core" tha~ " the core or chanr~al i8 601id iron. Thi~ 1~ aceo~uplished b~ separat~ng the core ~o that i~ducad currerLts ir~ the core c~ot ~low around in the core.

'7~

~ f`urther ebject of thi~ ventio~ i.s to provide a tran~-former ~hich the pr~ary impedance carL be increa~3ed or the thlckne~s-of ~he channel or core can be decre,asad9 theroby, decreaslng the rei~ght o~ the trangformer. Thi~ i~ acco~plished by ha~ing a capaci~or at the ~;econdary ~i~diag output and the capacltor value i.8 such a~ to CaUBe a dampad o~clllakion that ~ill cau~a an o~t of~pha~e ~lux to induce an oppo~i~g volta~o in ~he p.rlmary that ~qill t~nd to oppose tha appl~ ed Yoltags.

n~ D~ 0l15'0 O~ O L~5 Ill the dra~ g~ ~hich illu~trato ~bodima~ts o~ the lnve~tion:
Figure 1 la a~ ometr$c view of the ~mbediment;
Flguro 2 i8 ~ cllt~ ray view o~ the ~aDIe e~bodime~t;
Figure 3 is an electrical ~mbol of ~lgure 1; the parallsl line~; 1 bei~g placed on the outside of the ~lndings 9 and l O
si~,i:~y that the ~inding~ aro enclo8ed i~ ~ channel;
Fi~ure 4 i8 the same embodiment ~ith the c~pacitor 16 connected acro~c th0 secondary output 10 to lncrease the impedance of the prlmary 9;
Fig~rs 5 i8 the ~ymbol ~or the embodi~ent of Fig~re 1 with an added seco~dary wi~dln~ lL~ ~ith ca~acltor 16 to lncrea~a the impedance o~ the primary 9;
Fi~ure 6 i~ an ele~trical symbol o~ a raactance coll;
the coil con8i~t8 of the embodiment of Flgure 1 with only one Winding ln the chan~el;
Figure 7 ~8 th~ embo~lment o~ Figure 1 wlth tha channel constructed in the ~or~ of a tu~eO

7~5 DESCRIPTION OF T~IE P3~E~ERRED EMBODIM}~NT
~____ ~ eferrl~g to Figure 2 the core 1 con~3ists o~ two charl~e~ ~
5 and 6 and an in~er Recltion 2 to forii~ a clos0d ch~nel~ al~o re~err~d ~o-a~ loop. To a~ ble the tran~:~or~er the ~indin8~ 9 a~d 10 are placed over section 2 thell cha~el 5 ~d 6 ~re 81ipped over the dlug 9 a~d 10 ~o th~ core v~111 co~pletel~ ~urround ths wi~ding~
Tha hidden llno 4 i8 the ~ol~t b~tæesn tho k~qo channsl~ Tha s~ollar 3 i~ ce~ented or bolted to the core to make i.t rigld. Tllo hidden lina 8 r~prese~t~ the lnsulatlon that ~urrounds tha s~para~ion Jolnt 80 elec~rtc curr~s~t (kno~m a~3 eddy current~ ) cannot ~lo~ around the core, in the ~3arlle d:~rection aç~ the conductor~O The eellar 7 i~ Made oP iII{3ula~ing m~terial and i8 ceDD.e~ted o~ balted to the core 1 to make it rigi.d.. ~he lead 9 are the pri~ary ~ding and 10 the ~econdary wind:Lng lead~. The nu~bar t 1 r0preseIIt~ l~sulation ~or the lead~

I~ a tran~ormer, of the co~vantio~al type or the channel type a~ of the present inve:rltio~, the impedance o~ the prlmary windiD,g and the voltage i~dueed ln the ~eGondar~ winding will vary as the square of th~ numbeIc of tu3:~s in the ~ind~g, a~sumi~g the reluctance of the core doeli not chaage. For example, if tha priDlar;~
aDd secondary tur~s ar~ doubled and a~uming the reluctance of the core remain8 the same ~he impedanc e of the primary and voltage output or the 8econdary willd~g ~ill be increaf;ed four timel3. In the preceding 0xarnple whe~ the primar~ wiuding i8 doubled and a6~uming the same amount o:e currellk flo~s in the windin~ the ilux produced be doubled and t~o t~mo more flu~ utting tl7o tim~ more wire wlll i~nduce ~our tlme~3 more voltage in the ~ding . ~Iowever, due to the increa~e in reluct~nce o~ the core that results from a~ i~crease i~
the rlu~ber oi tu:r~s tha voltage and impodance of the wi.ndi~g~
~ot ~ary a~ tha l3quare of tkeincrea~e in the number of tur~, it will be le88 by an amount proportio~al to the i~cr2ase in reluctance.

The area oX a ~quara and a rectangle varles as the 6quare of i~B perime~ar, a~d simllarl~ ths area of a clrcl9 varle~ a~ the square of itB clrcumference, for e~ample, doubling the perlmeter w~ crea~e the area ~our ti~e~. The perimater of a recta~gle ~111 be greater than the peri~eter of a square which ha~ the sams area, and the perimetHr o~ a square ~ill be greater than the circu~ere~ce o~ a circle ~hich ha~ th0 ~ama area.
I~ th0 conv~ntienal shel:L type of tr~for~ar core khe ~indl~g area is rscta~gularp a~d by co~pari~ the ~ean flux path to the moa~ flu~ path o~ a ~qnare a~ in tha pre~t in~e~tion it i~
found that i~ the ~lndlng area of the ~h~nel i8 o~e~hal~ the wi~dlng area of the co~ve~tlonal tr~s~or~er, the me~-cross aection perimeter of the cha~el will be al~ost one half tho ~ea~ peri~eter of the conventio~al tranR~ormer wi~ding ~rea, a~d furthermora 3 iP khe cha~nel 1~ constructed i~ the form of a tube the mea~ perimeter wlll be le~5 ~han the 8quare channol by about ten per cent.
In the conve~tio~al shell type oi tran~Yormer th0 ~ g i8 wound around tho in~er ~ection of khe core and i~ the wlndi~g ha~
many ~r~ much of the wir6~ will ~ot be perpendicular to the lnner ~ection of the core and thereby ~uch ~ire will not produce a~y ~lu~.
Furthermore, ln the co~ventlo~al tran~or~er only one-halX oY the Winding i8 s~rrounded by tho core, and the cro~ ~ectional area Of tho c~re ior each hal~ ~ectio~ i8 one~half the eross ~ectionAl area Or the in~er ~ec~ o~ of the coro. This ~ill ha~e much the same effect a~ ~ one quarter o~ the winding were ~urrounded by a core having ~qual crog~ gectional aroa ag the inner æection area. I
8u~poc~ that o~l~ part of the magnekic field ~ill be e~ective in Producing flu~ i~ th0 coro9 that is, the ~ection o~ the winding that i8 surroundad bg ~he core, a~d in the other ~eGtion O~ the w~ding~

that i8 ~ot surrounded by the coro~ mo~t o~ the magnetic field will be repelled and it ~ill not exist.

~o I~ the pre~3e:llt inventlon the wlnding i~ in a c3iosed chalmel and the windi~g :~.8 comple~e:l;r 6urrolulded b~ the cha~nal, and by e:~t0nd1ng the ch~el more o:~ the; ~rl9~ will be perpe~dicular to the l~ner ~e6tion 2, and i.t ~ oæ~ e to lncrea3a the lerlgth of the ~13~ g and the nu~bor of tu:rus, thereby t :Increaslllg ths impsda;lce aIld induced ~olta~e mal1~g it po~ihlo to decrease the th:lLc~es~ o tbe chamlel and 81;111 ~ t~l~ the *~Rlclency o~ the trans~ormar .
In the pr0se~t irlve~tio~ lt 11 not practical to increaa~
the len~ th Or the ch~ l to a~ extent that .the n~ber o~ conductor3 i~ the channel become~ to ~all. ~ rule to ~ol~ otY i.8 to ha~e as ma~y co~duc~or~ a~ po~obla wlthout l~lcrea~ing the resi~tance o~ the g too much9 a~d mairltainl~,g thecro6s t3ection perimeter o~ the ChaIlrel a~3 RD~all as pok~ibl~ 9 and }Qaintai~l~g the le~gth o~ the Channel 80 that a alr ~ount o~ the co~dllctor~ w~ll be perpe~dicular to the in~er sectlo~ 2 of the core.
The cro~s ~ecl;ional area of the co~e 1 i~3 fo~d by mult:~plylng th~ thlc}s~:Le8~; o~ the charmel ~all b~ the mea~ length of the inner section 2. The maan le~gth i~ ~ound by addin~ four time~
the thiskness of the chan~ol to the inner ~ur~ace length o~ inner section 2. That i~, thicknel3s of channel ~ 1ongth o~ mean 1nner sect1o~ 2 = cros~ ~ectio~al are1a~ Fro~ the ~oregoing it can be ~een that ~ the 1eng~h Or the loop i~ incxeased t~ice as lo~g the cro~6 sectlo~al area o~ core 1 ~ill al~o be twics a~ Breat~ and be~ause the crog~ gectio~ per1meter of the core ha~ ~o~ bsen increa~ed the re1uct~ncO of the core will b~ docraa~ed by o~e-halX. Furtharmore, khe 10ngth of the conductors i~ the channe1 will have to be increased t~ice as much, and ~ihce the ~gnetic P1e1d i~ proportiona1 a10ng the le~gth of the conductors in thechanne1 the ma8natic fie1d wi11 al~o ba increase~d t~1ce as much, and the impedanc0 of the primaryj9 ~ill be doubled and the voltage output at the secondary 10 ~i11 al80 be Aoubled.

7~iS
1 ~

Re~erri~g to E'i~ure 2 the oiltsr conductorsg that i~, the Conductor~3 ~arthest from the l~ner ~ectio~ 29 ~or exaD~ple, a~ tha conductors ~alse the gO deKre~ corner or arc th~re will be ~om~ magnetic fleld whieh ~ill not bc able to pa~3 th:rough the inner section 2 an~
rurthermore the mag~atic ficld ~111 ba cro~ded in the cornar and lt opel aach other. Thi~ co~ Ltion ~ill be pra~0nt unly i~ the cor~er or ~here tho c~nduckors IDake ~ arc, or ~here th~ ma~etlc f~eld i8 ~able to pass throu~Sh the inne:r ~ection 2 becau~a it w:lll not ~hiit; iro~ itæ p~rpendlcular pOI3itiO~ ~lth the conductor~.
~ ai~errln~ to Fig~re 2 the wi~ g 9 i~ the priLmary ~:Lnding a~d 10 i~; the ~econdary ~ di~. The paper insulator 13 insulate~3 the t~o ~lDdings 9 and 10 ~rom each other al~o, if ne~e~Bary irl8ulation can ba u~ed bets~ea~ sach oach la~er o:~ ths ~din~s. The insulator 1~2 ial8~21at98 the two ~ g~ 9 and 10 ~rool the core lo ~l~o, the ~indtng~ ~ui3t have ~gid eupport ~ith re~peck to tha channel 80 that they will not mo~e by the ~orce~ o~ the magnet:Lc field.
When a~ alter~at~ g voltage i~ appli~d to the primary ~indi~ ~ current wlll ~lo~r throu~ the primary, howevar, as the current increases a ma~etic ~ield will ri~e around the conductor~
and thi~ ~ield ~ill cut t~e ad~acent conducltor~ oi~ the primary and ~nduce a voltage ~ tham which ~ll be i.n revarsa poarity to the applled voltage and it ~ilJ. telld to oppo~e it~ It i8 im~or~ant that the core bo ~ade larga enough B0 th~t ~u~X~eient m~grletic field is produced 80 the induced opposing voltage ~ill bo hi~h enough to almost completely oppo~e the applied ~oltage, this wlll make the transformer e~ric:iellt. The ~ag~etic Ileld wl ll al~o c~t the conductors of the secondary 10 a~d induce a voltage in them and r there i8 a load acro~ the secorL~ary current srill flo~ in the ~econdary and a ~a~etlc f~eld wlll r~e around the ~econdary that will be i~ direct oppo~ tloll, orone~halI cycle out of phase" to the field produced by the primary 9, a~d thi~ ~ield wi.ll oppo~e the ~ield o:~ the prizllar;y and it will cancel ~o~e o~ it the amount dep~nd~ on the current flowi~g 1~ the secondary 1 û.

'7~5 As the ~iel~ of the ~0co~dary ea~cel~ some o~ the primary f~eld the i~pedance o~ theprimary wlll ba decrea~ad ~d more currsnt ~ill flow in the primary 9 cau~ing more mag~etlc field around the pri~ary and as a result electrical energy 1~ tra~sformed from the pr~mar~ to the econdary windln~.
~ iYhe~ the mag~e~iG ~ield :riaes around the pr~ary 9 it psnetrata~ ths cora 1 and lt ~nduce~ a ~mall curre~t in tha core, the directlo~ o~ the current i~ tha ~a~e a~ the current or voltage induced in the ~eco~dary 10, an~ i e thi~ curre~t i8 per~itted to ~low the magnotic field produced ~ro~ this current ~ill oppose the ~agnetic ~ield of the pri~ary cau~ing ~o.re current to ~lo~ 1~ tha primary a~d a~ a resalt th~ e~iic~o~cy of the tra~ormer ~111 be decrea~ed~ This eifect ~ill be ~ore noti¢able ~he~ no current i8 Plowi~g i~ the secondary because whe~ curre~t flows in the a~condary the field of the seconda~y ~111 te~d to canc~l or indur~ à ~oltage i~ the core 1 which ~ill oppo~e the voltage induced i~ the core by the pri~ary. To p~event the current ~rom flowi~ around in the core the core is ~eparated at 8 i~ Figure 2 ~o that current ca~ot ~low completely around ln the cor~. There 18 ~till a pos~ibility that a 8mall curre~t ~ould flo~in the core, for example, when tha fleld ri~es around the prlmary 9 and a~ lt penetrate~ the i~er ~all of the c~re 1 acurre~t could flow in the in~er wall and retu~n by the outer ~all, ho~ever, the curre~t flowing ln the inner wall ~ould produce .
a flold ~hat would te~d to oppo~e the fleld of the prlmar~ but the field produced by the current flowi~g bac~ in the outer~wall would produce a:field that ~ould add to.the field of the primary and the two fields in the core would be neutralized and the transformer efficie~cy ~ould not be decrea~sd~
Re~erri~g to ~igure 79the-tra~for~er functions the same a~ the tra~or~er d~ ~igure ~, except that the s~uare iro~ ch~n~el is i~ the ~orm of a tube.~~

There i~3 an advanta~ e ~o buildi~g the chAnnel a~ a tuba, due to the cro;~3 section p~rimeter of the tube lbei~g la~8 thaIl the cros~
6ection perimeter o~ of a 6quare havi~ag the same wiDdirlg area, the tran~;former charmel whe~ built as a tubo w~ 11 hav0 ~ lower reluctanoe becau~e the flux will not hava to travel as far a~ it would if the tube ~ere a ~quare. The tra;~Ior~o:~ o:e Flgure 7 i~ bullt by partlally cuttlng two half sectlo~a o~ kube and bendl~g them to form a ~quare rlng. The wlnding i~ placad ila~o hal~ ~actlorl 21 ~nd the other h~lf sectlon 20 is abutt~d to halI secl;lon 21 a~d 6ecured by cla~p~ 18.
Thel l~ne 17 r~pra~3ent3 t~Le joint botw0en the t~o half ~action~ 20 and 21. Tho cor~Lor~ oX th~ eore 1 ara onrLtted bacau~e only the part ~fthe wlnding which i~ perpe~d~cular to the inner ~ost sectlon Of core 1 wlll be e~ ctive ln producl~g flu~. B~ omittlnæ the corners the trans~ormer ~a~ bs made wit~ le88 iro~ re~ultl~g 1~ a trang~or~r co~iderably ligh~er. A gap-22 ia ~ai~tained te prevent the flow o~ iuduced curre~t (eddy curre~ts) around thxough the core 1 The clamp 18 can be made o~ metal or alumi~um of suf ficient thiG~ne~B
to secure the two half ~ec~ion~ 20 and 21 seGuraly. The in~ulator 19 assurja ~ha~ the cla~p 18 will not ~hort circ~it the core 1 and the gap 22 ~ill be maintained.
Where lt i8 de~irad to hava a trans~ormer that wlll be light or whore portability i8 desirod or ~here a ~ery high primary impeda~ce i8 deg~.red the arra~geme~t of ~lgure 4 will produce that e~ec~. The capacity o~ the capacitor 16 ~8 chosen 80 it will ~or~
an oscillatl~g circuit wlth the sccondary wl~di~g 10. The oBcillati~nR
will cau8a a vol1;ago to b~ i~duced in the primar~ 9 which ~ill oppo~e the applied voltage, that i8, the voltage applled acro~s the primary 9.
For every quarter cycle there i~ a change in the direction o~ the ~agnetic field, for axample, whes tha current in the primary is rising the ~ield will a:Lso be ri~ing and after the quarter sycle, when the curre~t ha~ reached maximum a~d is decrea~ing, the magnetic field will decrea~e and aSter the current ha~ reached zero and ri~e~ in the oppo~ite direction the magnetlG ~ield ~ill again be increasing in an oppo~ite directlo~.

t~
1~

When the curren~ in the pri~ar~ 3 rislr~g the ~ield o:e the prlmary will ~duce a curre~t in the secondary 1() lthat wlll be 180 degrses or one half cycle out of phase with ~he pri~ar~r currell~;, and the field of the secondary will be ln a poeition to ir~duce a voltage i~, the primary that ~ill add to the appliad voltage~, Now, ~ the phase Q~ the currexl~ ln tha ~aeondary 10 i~ caused to lsad or la~ by 90 degrees or one quarter cycle the field o~ ths ~eco~dary w~ Lduce a ~olta~e i~ kha pri.~ary th~Lt ~ill oppo~e the applled voltage. Thi~
1~ poæsible becallse ~or e~rer~r quarter cycle 1;here i~ a reYer~al o~
magne~,ic ~ield . I~ aD. oscill~ting cirG ait the currsnt i8 ln pha~e with the volta~e ) and the ~urrent that sU~taill8 the o~Gillation l~U~3t A1RO be in phase. Ix~ Figure 4 the current that ~u~tain~ the oscillat~
lo~ 13 induced i}l the seco3~dary by the prl~ary magnetic ~iald and th0 08Cillati~lg cllrre~t in the secondary Hrill leed thl.s curre~t by about o~e qu~i~t~r cyele o~ . 90 degrees . A1~;0D the osclllating current in the aeco~dary will produc~ a flux in the cora that will ~aintain the ~;ecolldalry output ~oltag~. The o~cillation~ in the secondar~
Circu:Lt are a dalaped o~cillation, that 159 lf the ircuit o~cillated fully the voltage across the ~condary and capac~tor would be ver~
high; this is ~mpossible because as the Yoltage ri8e8 higher than the output voltage o:e the s0colldary the opposing voltage induced in the primary would be h:Lghe~ than the Applied voltage and no current ~r Wou3.d ~low, and there would be no cura~ent ~o ~ustai~ the o~cillation.

.

In Fig~lre 5 the capacltor 16 i~ co~ected acro~ a separate windirlg and the same result i obta:i~ed~
With the 0~3cillating circuit it is possibls to reduce the weight o~ the core and ~till maintain a hlgh primary impedarlce, or by maintaini~g the~ e æ~ ze of core and U8~D.g the o~cillati~g circuit to greatly increla~0 the prlmary lmped~ceO
To deGrea~;e the ~eight of the core the wallæ are m~ule thiImer so tha~ the tra~sforJner will still function without drivi~g the cora to sa~lratio~, this will cause the primar~ curre~t to be l~creaRed ,.

.i5 Now,~hen the capacltor i~ connected acros~ the secondary the oscillati~g ~lux ~111 c~u~ed the primary current to decrease appro~imAtely to its original ~alua, and the tr~n~for~er will fu~ctlon ~uch the same a~ be~ore the walls of the ch~nnel ~ere ~ade thinner.
In the rOregoi~g it 1~ a~su~ed that, be~ore the ~all~ o~ khe channel ~ere made thinner, the transfor~er had a high effici~ncy and the core wa~ not driven clo~e to 3aturatlon. ~180 ~ ~h9n the capaci~or i8 U~ed to decroa~e the weight of the eors, a6 in the foregoing, tha thickness o~ the chaarel mus~ ba thlck enough ~o th~t khe oscillating cirCuit does not ~riYe tha core t~ saturation.
The embodi~e~t Or Figure 1 ca~ be u~ad a8 a reactance Coil, The reactacG0 of the coil will depend upon the 8ize 0~ the core 1 and the la~gth of çon~uctor~ in the ch~nnel. I~ an air gap i8 requlred the width of the inner section 2 could be d~creased 80 that an air gap tlrould ~xi~t bstween the inner ~ec tion 2 and the Channel 5 and 6. The parallel lines 1 l~dicate that the winding 15 ide the channal.
I halro rou~d that adding a capacitor to the æecondary output o:~ a convantlon~l electri c transformer a~d lf the capacitor uch that it ~111 cau~s an oscillation ~ith the ~econdary windirlg the primar~ impedanc~ Or that krasrormer ~ill be greatly increa~ed.
It is k~o~ that ~ome conve~tlonal ~hell type OI core tranaformero ha~e b~en b~ilt ~ith an efficiency of 99 per cent.
I ~uspect thal; thi~ would be under full load co~dl tion a~ it could not po~a~bly be under no load condition becau~e o~ the prlmary curren~ By adtin~ a capacitor acro~ the ~eco~dary ~inding of ~uch a tran~formar the efficiency ~rould be i~crt-~ased for no load c onditio~ and f or small load c ondition~ .

Claims (12)

The embodiments of the invention in which an exclusive property or privilage is claimed are defined as follows:

1. An electrical transformer having a maximum frequency limit of 500 Hertz, comprising of a primary and secondary winding which are surrounded by the walls of a square closed iron channel, and the said channel is made of solid iron, and the walls of the said channel constitutes the core of the transformer, and the said primary and secondary winding and said channel are extended to form a square ring.

2. A device as claimed in claim 1, in which the channel is constructed in three main parts,a flat iron strip which forms the inner most section of the said channel, and two sections of channel are abutted with the flat strip to form a square ring, and the channel section and the flat strip are secured together by at least two collars.

3. A device as claimed in claim 1, in which the walls of the square channel are cut perpendicular to the windings and separated slightly to prevent eddy currents from flowing lengthwise in the said channel, and said channel being free of lamination.

4. A device as claimed in claim 1, in which means are provided to decrease the reluctance of the channel, said means comprising of constructing the cross section of the said channel round as a tube.

5. A device as claimed in claim 4, in which the channel of the transformer comprises of two half sections of a tube which forms a square ring, the winding are placed in one half section of the tube and the other half section is abutted to the former section to form a tube, and the two half sections of tube are secured together with collars, and said collars being part of a cover that covers the corners of the said windings.

6. A device as claimed in claim 4 and 5, in which means are provided to decrease the weight of the channel, said means comprising of omitting the corner sections of the said channel, thereby, maintaining only the section of the said channel in which the inner most part of the said channel is perpendicular to the windings.

7. A device as claimed in claim 1 and 4, in which improved heat dissipation of the transformer is provided as compared to a conventional transformer where the windings surround the core, because the channel surrounds the primary and secondary windings, thereby, providing a greater surface area for the dissipation of heat.

8. A device as claimed in claim 1 and 4, having a maximum frequency limit of 500 Herzt, in which means are provided to convert the electric transformer to an inductive reactance coil, said means comprising of using the primary and secondary windings to act a the windings or a reactance coil.

9. An electrical transformer comprising of a primary and secondary winding and an iron core and having a maximium frequency limit of 500 Herz, in which means are provided to increase the efficiency of the transformer, said means comprising of a capacitor connected across the secondary winding, and the capacity of the capacitor boing of such value that it will form an oscillating circuit with the secondary winding, and produce an oscillating flux in the core and said flux being of Such magnitude that the core will not be driven into saturation by said oscillating flux.

10. A device as claimed in claim 9, in which the oscillating flux in the core induces a voltage in the primary winding which tends to oppose the applied voltage of the primary and increase the impedance of the primary winding, thereby, increasing the efficiency of the transformer.

11. A device as claimed in claim 9 and 10, in which the capacitor can be connected across any one of the secondary windings where the transformer has more than one secondary winding

12. A device as claimed in claim 1 and 4, in which means are provided to decrease the weight of the channel, said means comprising of the oscillating flux in the core produced by the capacitor across the secondary winding, causing the efficiency of the transformer to be increased, thereby, making it possible to decrease the thickness of the said channel walls, and the said channel walls being decreased to all extent that the said channel will not be driven into saturation.