vector group of

8/12/2019 Vector Group Of

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Vector Group of Transformer

MAY 23, 2012 43 COMMENTS

Introduction:

Three phase transformer consists of three sets of primary winin!s, one for each phase, an threesets of seconary winin!s wo"n on the same iron core# Separate sin!$e%phase transformers can

&e "se an e'terna$$y interconnecte to yie$ the same res"$ts as a 3%phase "nit#

The primary winin!s are connecte in one of se(era$ ways# The two most commonconfi!"rations are the e$ta, in which the po$arity en of one winin! is connecte to the non%

po$arity en of the ne't, an the star, in which a$$ three non%po$arities )or po$arity* ens are

connecte to!ether# The seconary winin!s are connecte simi$ar$y# This means that a 3%phasetransformer can ha(e its primary an seconary winin!s connecte the same )e$ta%e$ta or star%

star*, or ifferent$y )e$ta%star or star%e$ta*#

+ts important to remem&er that the seconary (o$ta!e wa(eforms are in phase with the primarywa(eforms when the primary an seconary winin!s are connecte the same way# This

conition is ca$$e -no phase shift#. /"t when the primary an seconary winin!s are connecteifferent$y, the seconary (o$ta!e wa(eforms wi$$ iffer from the corresponin! primary (o$ta!e

wa(eforms &y 30 e$ectrica$ e!rees# This is ca$$e a 30 e!ree phase shift# hen twotransformers are connecte in para$$e$, their phase shifts m"st &e ientica$ if not, a short circ"it

wi$$ occ"r when the transformers are ener!ie#.

Basic Idea of Winding:

An ac (o$ta!e app$ie to a coi$ wi$$ in"ce a (o$ta!e in a secon coi$ where the two are

$ine &y a ma!netic path# The phase re$ationship of the two (o$ta!es epens "pon whichways ro"n the coi$s are connecte# The (o$ta!es wi$$ either &e in%phase or isp$ace &y 10

e!

hen 3 coi$s are "se in a 3 phase transformer winin! a n"m&er of options e'ist# Thecoi$ (o$ta!es can &e in phase or isp$ace as a&o(e with the coi$s connecte in star or e$ta

an, in the case of a star winin!, ha(e the star point )ne"tra$* &ro"!ht o"t to an e'terna$

termina$ or not#

Six Ways to wire Star Winding:
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Six Ways to wire Delta Winding:
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Polarity:

An ac (o$ta!e app$ie to a coi$ wi$$ in"ce a (o$ta!e in a secon coi$ where the two are

$ine &y a ma!netic path# The phase re$ationship of the two (o$ta!es epens "pon whichway ro"n the coi$s are connecte# The (o$ta!es wi$$ either &e in%phase or isp$ace &y 10

e!#

hen 3 coi$s are "se in a 3 phase transformer winin! a n"m&er of options e'ist# Thecoi$ (o$ta!es can &e in phase or isp$ace as a&o(e with the coi$s connecte in star or e$ta

an, in the case of a star winin!, ha(e the star point )ne"tra$* &ro"!ht o"t to an e'terna$

termina$ or not#
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hen 5air of Coi$ of Transformer ha(e same irection than (o$ta!e in"ce in &oth coi$

are in same irection from one en to other en# hen two coi$ ha(e opposite winin! irection than 6o$ta!e in"ce in &oth coi$ are in

opposite irection#

Winding connection designations:

First Symbol:for High Voltage7 A$ways capita$ $etters#

898e$ta, Y9Star, :9+nterconnecte star, N9Ne"tra$ Second Symbol: forLow voltage7 A$ways Sma$$ $etters#

98e$ta, y9Star, 9+nterconnecte star, n9Ne"tra$#

Third Symbol:5hase isp$acement e'presse as the c$oc ho"r n"m&er )1,;,11* Example Dyn!!

Transformer has a e$ta connecte primary winin! )D* a star connecte seconary )y* with

the star point &ro"!ht o"t )n* an a phase shift of 30 e! $eain! )!!*#

The point of conf"sion is occ"rrin! in notation in a step%"p transformer# As the+EC;006 in se?"ence# @or e'amp$e, a step%"p

transformer with a e$ta%connecte primary, an star%connecte seconary, is not written as

Y11B, &"t Y11B# The 11 inicates the >6 winin! $eas the =6 &y 30 e!rees# Transformers &"i$t to ANS+ stanars "s"a$$y o not ha(e the (ector !ro"p shown on

their namep$ate an instea a (ector ia!ram is !i(en to show the re$ationship &etween the

primary an other winin!s#

Vector Group of Transformer:

The three phase transformer winin!s can &e connecte se(era$ ways# /ase on the

winin!s connection, the (ector !ro"p of the transformer is etermine# The transformer (ector !ro"p is inicate on the Name 5$ate of transformer &y the

man"fact"rer#

The (ector !ro"p inicates the phase ifference &etween the primary an seconary sies,intro"ce "e to that partic"$ar confi!"ration of transformer winin!s connection#
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The 8etermination of (ector !ro"p of transformers is (ery important &efore connectin!

two or more transformers in para$$e$# +f two transformers of ifferent (ector !ro"ps are

connecte in para$$e$ then phase ifference e'ist &etween the seconary of the transformersan $ar!e circ"$atin! c"rrent f$ows &etween the two transformers which is (ery etrimenta$#

Phase Displacement between HV and V Windings:

The (ector for the hi!h (o$ta!e winin! is taen as the reference (ector# 8isp$acement of

the (ectors of other winin!s from the reference (ector, with antic$ocwise rotation, is

represente &y the "se of c$oc ho"r fi!"re# +S7 202; )5art 16*%16 phasor is in phase with the =6 phasor

8i!it 1 930D $a!!in! )>6 $a!s =6 with 30D* &eca"se rotation is anti%c$ocwise# 8i!it 11 9 330D $a!!in! or 30D $eain! )>6 $eas =6 with 30D*

8i!it H 9 1H0D $a!!in! )>6 $a!s =6 with 1H0D*

8i!it ; 9 10D $a!!in! )>6 $a!s =6 with 10D*

hen transformers are operate in para$$e$ it is important that any phase shift is the samethro"!h each# 5ara$$e$in! typica$$y occ"rs when transformers are $ocate at one site an

connecte to a common &"s &ar )&ane* or $ocate at ifferent sites with the seconary

termina$s connecte (ia istri&"tion or transmission circ"its consistin! of ca&$es an o(erhea$ines#

$hase Shi%t &Deg' (onnection

0 Yy0 80 80

30 $a! Y1 8y1 Y1

;0 $a! 82 82


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120 $a! 84 84

1H0 $a! YH 8yH YH

10 $a! Yy; 8; 8;

1H0 $ea Y< 8y< Y6 $eain! =6

!loc" #otation: $
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Points to be consider while +electing of Vector Group:

6ector Iro"ps are the +EC metho of cate!oriin! the primary an seconary winin!

confi!"rations of 3%phase transformers# inin!s can &e connecte as e$ta, star, or

interconnecte%star )i!a!*# inin! po$arity is a$so important, since re(ersin! theconnections across a set of winin!s affects the phase%shift &etween primary an seconary#

6ector !ro"ps ientify the winin! connections an po$arities of the primary an seconary#

@rom a (ector !ro"p one can etermine the phase%shift &etween primary an seconary#

Transformer (ector !ro"p epens "pon

K .emoving harmonics:8y connection L y winin! n"$$ifies 3r harmonics,

pre(entin! it to &e ref$ecte on e$ta sie#

K $arallel operations:A$$ the transformers sho"$ ha(e same (ector !ro"p

po$arity of the winin!#K Earth %a*lt .elay:A 8 transformer oes not ha(e ne"tra$# to restrict the earth

fa"$ts in s"ch systems, we may "se i! a! wo"n transformer to create a ne"tra$ a$on!with the earth fa"$t re$ay##

K Type of Non >iner >oa7 systems ha(in! ifferent types of harmonics non

$inear Types of $oas e#!# f"rnace heaters ,6@8S etc for that we may "se 8yn11, 8yn21,8yn31 confi!"ration, wherein, 30 e!# shifts of (o$ta!es n"$$ifies the 3r harmonics to

ero in the s"pp$y system#
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K Type o% Trans%ormer /pplication:Ienera$$y for 5ower e'port transformer i#e#

!enerator sie is connecte in e$ta an $oa sie is connecte in star# @or 5ower e'port

import transformers i#e# in Transmission 5"rpose Transformer star star connection may &epreferre &y some since this a(ois a !ro"nin! transformer on !enerator sie an perhaps

sa(e on ne"tra$ ins"$ation# Most of systems are r"nnin! in this confi!"ration# May &e $ess

harmf"$ than operatin! e$ta system incorrect$y# Y or 8y connection is stanar for a$$"nit connecte !enerators#

K There are a n"m&er of factors associate with transformer connections an may

&e "sef"$ in esi!nin! a system, an the app$ication of the factors therefore etermines the&est se$ection of transformers# @or e'amp$e7

For selecting Star (onnection:

A star connection presents a ne"tra$# +f the transformer a$so inc$"es a e$ta winin!, that

ne"tra$ wi$$ &e sta&$e an can &e !ro"ne to &ecome a reference for the system# Atransformer with a star winin! that oes NOT inc$"e a e$ta oes not present a sta&$e

ne"tra$#

Star%star transformers are "se if there is a re?"irement to a(oi a 30e! phase shift, if

there is a esire to constr"ct the three%phase transformer &an from sin!$e%phase transformers,or if the transformer is !oin! to &e switche on a sin!$e%po$e &asis )ie, one phase at a time*,

perhaps "sin! man"a$ switches# Star%star transformers are typica$$y fo"n in istri&"tion app$ications, or in $ar!e sies

interconnectin! hi!h%(o$ta!e transmission systems# Some star%star transformers are e?"ippe

with a thir winin! connecte in e$ta to sta&i$ie the ne"tra$#

For selecting Delta (onnection:

A e$ta connection intro"ces a 30 e$ectrica$ e!ree phase shift#

A e$ta connection traps the f$ow of ero se?"ence c"rrents#

For selecting Delta0Star (onnection:

8e$ta%star transformers are the most common an most !enera$$y "sef"$ transformers#

8e$ta%e$ta transformers may &e chosen if there is no nee for a sta&$e ne"tra$, or if there

is a re?"irement to a(oi a 30 e$ectrica$ e!ree phase shift# The most common app$ication of ae$ta%e$ta transformer is as tan iso$ation transformer for a power con(erter#

For selecting 1ig 2ag (onnection:

The :i! :a! winin! re"ces (o$ta!e "n&a$ance in systems where the $oa is not e?"a$$yistri&"te &etween phases, an permits ne"tra$ c"rrent $oain! with inherent$y $ow ero%

se?"ence impeance# +t is therefore often "se for earthin! transformers#

5ro(ision of a ne"tra$ earth point or points, where the ne"tra$ is referre to earth either

irect$y or thro"!h impeance# Transformers are "se to !i(e the ne"tra$ point in the maorityof systems# The star or interconnecte star ):* winin! confi!"rations !i(e a ne"tra$ $ocation#

+f for (ario"s reasons, on$y e$ta winin!s are "se at a partic"$ar (o$ta!e $e(e$ on a partic"$ar

system, a ne"tra$ point can sti$$ &e pro(ie &y a p"rpose%mae transformer ca$$e a ne"tra$earthin!#

For selecting Distrib*tion Trans%ormer: The first criterion to consier in choosin! a (ector !ro"p for a istri&"tion transformer

for a faci$ity is to now whether we want a e$ta%star or star%star# Gti$ities often prefer star%

star transformers, &"t these re?"ire 4%wire inp"t feeers an 4%wire o"tp"t feeers )i#e#

incomin! an o"t!oin! ne"tra$ con"ctors*#


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@or istri&"tion transformers within a faci$ity, often e$ta%star are chosen &eca"se these

transformers o not re?"ire 4%wire inp"t a 3%wire primary feeer circ"it s"ffices to s"pp$y a

4%wire seconary circ"it# That is &eca"se any ero se?"ence c"rrent re?"ire &y the seconaryto s"pp$y earth fa"$ts or "n&a$ance $oas is s"pp$ie &y the e$ta primary winin!, an is not

re?"ire from the "pstream power so"rce# The metho of earthin! on the seconary is

inepenent of the primary for e$ta%star transformers# The secon criterion to consier is what phase%shift yo" want &etween primary an

seconary# @or e'amp$e, 8y11 an 8yH transformers are &oth e$ta%star# +f we ont care

a&o"t the phase%shift, then either transformer wi$$ o the o 5hase%shift is important whenwe are para$$e$in! so"rces# e want the phase%shifts of the so"rces to &e ientica$#

+f we are para$$e$in! transformers, then yo" want them to ha(e the same the same (ector

!ro"p# +f yo" are rep$acin! a transformer, "se the same (ector !ro"p for the new transformer,

otherwise the e'istin! 6Ts an CTs "se for protection an meterin! wi$$ not wor proper$y# There is no technica$ ifference &etween the one (ector !ro"ps )i#e# Y1* or another

(ector !ro"p )i#e# Y11* in terms of performance# The on$y factor affectin! the choice

&etween one or the other is system phasin!, ie whether parts of the networ fe from the

transformer nee to operate in para$$e$ with another so"rce# +t a$so matters if yo" ha(e ana"'i$iary transformer connecte to !enerator termina$s# 6ector matchin! at the a"'i$iary &"s

&ar

,pplication of Transformer according to Vector Group:

-%. -Dyn%%/ Dyn%/ 0#d%/ 0#d%%.

Common for istri&"tion transformers#

Norma$$y 8yn11 (ector !ro"p "sin! at istri&"tion system# /eca"se Ieneratin!Transformer are YN1 for ne"tra$iin! the $oa an!$e &etween 11 an 1#

e can "se 8yn1 at istri&"tion system, when we are "sin! Ienerator Transformer are

YN11#

+n some in"stries ; p"$se e$ectric ri(es are "sin! "e to this Hthharmonics wi$$ !enerateif we "se 8yn1 it wi$$ &e s"ppress the Hth harmonics#

Star point faci$itates mi'e $oain! of three phase an sin!$e phase cons"mer

connections# The e$ta winin! carry thir harmonics an sta&i$ies star point potentia$#

A e$ta%Star connection is "se for step%"p !eneratin! stations# +f =6 winin! is star

connecte there wi$$ &e sa(in! in cost of ins"$ation# /"t e$ta connecte =6 winin! is common in istri&"tion networ, for feein! motors

an $i!htin! $oas from >6 sie#

-&. +tar1+tar -0y$ or 0y).

Main$y "se for $ar!e system tie%"p Transformer#

Most economica$ connection in =6 power system to interconnect &etween two e$tasystems an to pro(ie ne"tra$ for !ro"nin! &oth of them#

Tertiary winin! sta&i$ies the ne"tra$ conitions# +n star connecte transformers, $oa

can &e connecte &etween $ine an ne"tra$, on$y if)a* the so"rce sie transformers is e$ta connecte or

)&* the so"rce sie is star connecte with ne"tra$ connecte &ac to the so"rce ne"tra$#

+n This Transformers# +ns"$ation cost is hi!h$y re"ce# Ne"tra$ wire can permit mi'e

$oain!#


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Trip$e harmonics are a&sent in the $ines# These trip$e harmonic c"rrents cannot f$ow,

"n$ess there is a ne"tra$ wire# This connection pro"ces osci$$atin! ne"tra$#

Three phase she$$ type "nits ha(e $ar!e trip$e harmonic phase (o$ta!e# =owe(er threephase core type transformers wor satisfactori$y#

A tertiary mesh connecte winin! may &e re?"ire to sta&i$ie the osci$$atin! ne"tra$

"e to thir harmonics in three phase &ans#-2. Delta 3 Delta -Dd $ or Dd ).

This is an economica$ connection for $ar!e $ow (o$ta!e transformers# >ar!e "n&a$ance of $oa can &e met witho"t iffic"$ty#

8e$ta permits a circ"$atin! path for trip$e harmonics th"s atten"ates the same#

+t is possi&$e to operate with one transformer remo(e in open e$ta or. 6. connectionmeetin! H percent of the &a$ance $oa#

Three phase "nits cannot ha(e this faci$ity# Mi'e sin!$e phase $oain! is not possi&$e

"e to the a&sence of ne"tra$#

-'. +tar14ig15ag or Delta14ig15ag -05 or D5.

These connections are emp$oye where e$ta connections are wea# +nterconnection ofphases in i!a! winin! effects a re"ction of thir harmonic (o$ta!es an at the same time

permits "n&a$ance $oain!#

This connection may &e "se with either e$ta connecte or star connecte winin! eitherfor step%"p or step%own transformers# +n either case, the i!a! winin! pro"ces the same

an!"$ar isp$acement as a e$ta winin!, an at the same time pro(ies a ne"tra$ for earthin!

p"rposes#

The amo"nt of copper re?"ire from a i!a! winin! in 1H more than a corresponin!star or e$ta winin!# This is e'tensi(e$y "se for earthin! transformer#

8"e to 2ig2ag connection )interconnection &etween phases*, thir harmonic (o$ta!es are

re"ce# +t a$so a$$ows "n&a$ance $oain!# The i!a! connection is emp$oye for >6winin!# @or a !i(en tota$ (o$ta!e per phase, the i!a! sie re?"ires 1H more t"rns as

compare to norma$ phase connection# +n cases where e$ta connections are wea "e to $ar!e

n"m&er of t"rns an sma$$ cross sections, then i!a! star connection is preferre# +t is a$so"se in rectifiers#

-(. 4ig1 5ag6 star -40% or 4y%%.

:i!a! connection is o&taine &y inter connection of phases#4%wire system is possi&$e on

&oth sies# Gn&a$ance $oain! is a$so possi&$e# Osci$$atin! ne"tra$ pro&$em is a&sent in this

connection# This connection re?"ires 1H more t"rns for the same (o$ta!e on the i!a! sie an

hence costs more# =ence a &an of three sin!$e phase transformers cost a&o"t 1H more than

their 3%phase co"nterpart# A$so, they occ"py more space# /"t the spare capacity cost wi$$ &e

$ess an sin!$e phase "nits are easier to transport# Gn&a$ance operation of the transformer with $ar!e ero se?"ence f"namenta$ mmf

content a$so oes not affect its performance# E(en with Yy type of po$y phase connection

witho"t ne"tra$ connection the osci$$atin! ne"tra$ oes not occ"r with these cores# @ina$$y,three phase cores themse$(es cost $ess than three sin!$e phase "nits "e to compactness#

-). 0d(:

Main$y "se for machine an main Transformer in $ar!e 5ower Station an Transmission

S"&station#


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The Ne"tra$ point can &e $oae with rate C"rrent#

-*. 051(

@or 8istri&"tion Transformer "p to 2H0M6A for $oca$ istri&"tion system#

The Ne"tra$ point can &e $oae with rate C"rrent#

,pplication of Transformer according according to 7ses:

Step *p Trans%ormer:+t sho"$ &e Y1 or Y11#

Step down Trans%ormer:+t sho"$ &e 8y1 or 8y11# )ro*nding p*rpose Trans%ormer:+t sho"$ &e Y1 or 811#

Distrib*tion Trans%ormer:e can consier (ector !ro"p of 8n0 which re"ce the

6*# The con(entiona$ metho is to connect the re phase on AFa, Ye$$ow phase on /F&, an

the /$"e phase on CFc#

Other phase isp$acements are possi&$e with "ncon(entiona$ connections )for instance reon &, ye$$ow on c an &$"e on a* /y oin! some "ncon(entiona$ connections e'terna$$y on

one sie of the Transformer, an interna$ connecte 80 transformer can &e chan!e either to a

84)%120D* or 8)J120D* connection# The same is tr"e for interna$ connecte 84 or 8

transformers#

&4' )ro*p 33: E'amp$e7 8; )10D isp$acement &etween =6 an >6*#

/y oin! some "ncon(entiona$ connections e'terna$$y on one sie of the Transformer, an

interna$ connecte 8; transformer can &e chan!e either to a 82)%;0D* or 810)J;0D*connection#

&5' )ro*p 333: E'amp$e7 8yn1 )%30D isp$acement &etween =6 an >6*#

/y oin! some "ncon(entiona$ connections e'terna$$y on one sie of the Transformer, aninterna$ connecte 8yn1 transformer can &e chan!e either to a 8ynH)%1H0D* or 8yn)J0D*

connection#

&6' )ro*p 3V: E'amp$e7 8yn11 )J30D isp$acement &etween =6 an >6*# /y oin! some "ncon(entiona$ connections e'terna$$y on one sie of the Transformer, an

interna$ connecte 8yn11 transformer can &e chan!e either to a 8yn


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Why 2$6 Sie or the !enerator sie of the IT is connecte in Star, with the Star sie

ne"tra$ &ro"!ht o"t#

The >6 sie (o$ta!e wi$$ -$a!. the =6 sie (o$ta!e &y 30 e!rees#
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Th"s, in a !eneratin! station we create a 30 e!rees $a!!in! (o$ta!e for transmission,

with respect to the !enerator (o$ta!e#

As we ha(e create a 30 e!rees $a!!in! connection in the !eneratin! station, it isa(isa&$e to create a 30 e!rees $eain! connection in istri&"tion so that the "ser (o$ta!e is

-in phase. with the !enerate (o$ta!e# An, as the transmission sie is 8e$ta an the "ser

mi!ht nee three phase, fo"r%wire in the >6 sie for his sin!$e phase $oas, the istri&"tiontransformer is chosen as 8yn11#

There is ma!netic co"p$in! &etween =T an >T# hen the $oa sie )>T* s"ffers some

ip the >T c"rrent try to !o o"t of phase with =T c"rrent, so 30 e!ree phase shift in 8yn%11eeps the two c"rrents in phase when there is ip#

So the (ector !ro"p at the !eneratin! station is important whi$e se$ectin! istri&"tion

Transformer#

Vector Group in Generating1Transmission1Distribution +ystem:

Ieneratin! TC is Y1 transmitte power at 400Q6, for 400Q6 to 220Q6 Yy is "se an

&y "sin! "d&etween e#!# 220 an ;; 6, then Dyfrom ;; to 11 6 so that their phase shifts

can &e cance$$e o"t# An for >6 )400F2306* s"pp$ies at H0 = are "s"a$$y 3 phase, earthene"tra$, so a -8yn. >6 winin! is neee# =ere IT sie %30$a! )Y1* can &e n"$$ify J30 &y

"sin! istri&"tion Transformer of 8y11# A reason for "sin! "d&etween e#!# 220 an ;; 6, then Dyfrom ;; to 11 6 is that

their phase shifts can cance$ o"t an +t is then a$so possi&$e to para$$e$ a 220F11 6 YY

transformer, at 11 6, with the ;;F11 6 )a YY transformer often has a thir, e$ta, winin!to re"ce harmonics*# +f one went 8y11 L 8y11 from 220 to 11 6, there wo"$ &e a ;0

e!ree shift, which is not possi&$e in one transformer# The -stanar. transformer !ro"ps in

istri&"tion a(oi that in of $imitation, as a res"$t of tho"!ht an e'perience $eain! to

$owest cost o(er many years#

Generator T! is 0d%/ !an we use Distribution T! Dy( instead of

Dy%%>

ith re!ars to theory, there are no specia$ a(anta!es of 8yn11 o(er 8ynH#

3n 3solation /pplication:+n iso$ate app$ications there is no a(anta!e or isa(anta!e

&y "sin! 8yH or 8y11# +f howe(er we wish to interconnect the seconary sies of ifferent8ny transformers, we m"st ha(e compati&$e transformers, an that can &e achie(e if yo"

ha(e a 8yn11 amon! a !ro"p of 8ynHBs an (ice (ersa#

3n $arallel (onnection:5ractica$$y, the re$ati(e p$aces of the phases remain same in8yn11 compare to 8ynH#

+f we "se Y1 Transformer on Ieneratin! Sie an 8istri&"tion sie 8y11 transformer

than %30 $a! of !eneratin! sie )Y1* is n"$$ify &y J30 >ea at Pecei(in! sie 8y11* so no

phase ifference respect to !eneratin! Sie an if we are on the =6 sie of the Transformer,an if we enote the phases as P% Y%/ from $eft to ri!ht, the same phases on the >6 sie wi$$

&e P% Y %/, &"t from $eft to Pi!ht#

This wi$$ mae the Transmission $ines ha(e same co$or )for ientification* whether it isinp"t to or o"tp"t from the Transformer#

+f we "se Y1 Transformer on Ieneratin! Sie an 8istri&"tion sie 8yH transformer

than %30 $a! of !eneratin! sie )Y1* is more $a! &y %1H0 >a! at Pecei(in! sie )8yH* soTota$ phase ifference respect to !eneratin! Sie is 10 e! )%30J%1H09%10* an if we are on


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the =6 sie of the Transformer, an if we enote the phases as P% Y%/ from $eft to ri!ht, the

same phases on the >6 sie wi$$ &e P% Y %/, &"t from Pi!ht to >eft#

This wi$$ mae the Transmission $ines ha(e No same co$or )for ientification* whether itis inp"t to or o"tp"t from the Transformer#

The ifference in o"tp"t &etween the 8yn11 an 8nyH an is therefore 10 e!rees#

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