EE403.15 1Name: A. Siva Sankar Designation: lecturerBranch :Electrical and Electronics Engg.Institution : Govt. Polytechnic, ProddaturSemester :I!a"or #o$ic :Single Phase #rans%ormersSu&to$ic : $hase diagrams and $ro&lems on e'uivalent resistance and reactanceSu&.(ode)#itle : EE*+,+ ) A( !achines*IDuration :-, min.#eaching Aids :PP#, AnimationsDEPA.#!EN# /0 #E(1NNI(A2 ED3(A#I/N AND1.A P.ADES1 EE403.15 2.eca$ In $revious $eriod, 4e learnt a&out 5Ideal #605#rans%erring resistance %rom one slide to another slide 5#rans%erring reactance and Im$edance %rom one slide to another slide EE403.15 3/&"ective:/n com$letion o% this $eriod, you 4ould &e a&le to understand5 #he $hasor diagrams o% real trans%ormer %or various load $o4er %actors5 Solve $ro&lems on %inding e'uivalent resistances orreactance or im$edances o% a trans%ormerEE403.15 4D3.A#I/N #/ (/E. EA(1 /B7E(#IE5#he $hasor diagrams o% real trans%ormer %or various load $o4er %actors 8,!in51o4 to solve $ro&lems on %inding e'uivalent resistances or reactance or im$edances o% a trans%ormer8-!in5Summary ) 'uestionsSummary ) 'uestions,-!in ,-!inEE403.15 5Phasor diagrams o% $ractical trans%ormer5As the $hasor diagrams are re$resentations o% e'uations o% &oth current and voltage, the e'uations re$resenting trans%ormers are given &elo4 : 1 1 11 1 1 112 0 10jX R Z whereZ I E VI I II I Iw+ =+ =+ =+ =EE403.15 6 , 90. . :,02 12'22 2 22 2 2 2flux mutual the to lagging areE and E fs m e induced The NoteKI IandjX R Z WhereZ I E V=+ = =9EE403.15 7Note:5:hile dra4ing $hasor diagrams, the vectors %or resistive dro$s ; < are dra4n $arallel to current vectors and the reactive dro$s;< are $er$endicular to the current vectors as $er the vector e'uations o% $rimary 4inding and secondary 4indings.IRIXEE403.15 8Phasor diagramsI2V2I2R2E2I012I1E I1R11I01V1Fig: Phasor diagram for resistive loadI2X2I1X1EE403.15 9Phasor diagramsI2V2I2R2E2I012I1E I1R11I01V1Fig 2: Phasor diagram for inductive loadI2X2I1X12EE403.15 10Phasor diagramsI2V2I2R2E2I012I1E I1R11I01V1Fig 3: Phasor diagram for capacitive loadI2X2I1X12EE403.15 11#he %ollo4ing $oints are noted %rom the a&ove $hasor diagrams:5In case o% resistive load the terminal voltage is less than the induced e.m.%. and it %alls 4ith increase in load or secondary current .5In case o% inductive load =.*2 load>, the terminal voltage is less than the induced e.m.%.In this case the %all in terminal voltage is more.5 In case o% ca$acitive load =.*( load>, the terminal voltage is more than the induced e.m.%EE403.15 12A 8?,6+9,, single*$hase trans%ormer has a $rimary resistance o% ,.8@ and leakage reactance o% ,.-@ and the corres$onding values %or the secondary are ,.A-@ and B.C@ res$ectively. 0ind the secondary terminal voltage 4hen su$$lying B,A at ,.C $o4er %actor laggingEDam$le B:EE403.15 13Solution:5Given Data:( )22304608 . 0 cos8 . 175 . 0 5 . 02 . 01222211= = == = = = =EEKlagXRXREE403.15 14 =+ =+ = == = 55 . 12 . 0 4 75 . 0resistance86 . 36 1086 . 36 ) 8 . ( cos02122 02020 12x RR K R RSecondary to referredeui!alent that "now We# I$Solution:EE403.15 15E'uivalent reactance re%erred to secondary, #otal im$edance re%erred to secondary, =+ =+ =8 . 35 . 0 4 8 . 12122 02x XX K X X$ =+ =+ =00202 02 28 . 67 1 . 48 . 3 55 . 1 j ZX R Z$Solution:EE403.15 16Secondary terminal voltage,{ }{ }{ }Vjj jjx VZ I E V000 0 022 2 2 284 . 2 35 . 425079 . 21 8 . 424079 . 21 165 . 35 0 46094 . 30 41 0 4608 . 67 1 . 4 86 . 36 10 0 460 = =+ + = + = = =Solution:EE403.15 17Summary In this $eriod, you learnt a&out 5Phase diagram5Solve some $ro&lemsEE403.15 18B. #he secondary terminal voltage 8 is ********that o% secondary induced e.m.%. in case o% ca$acitive load.A> 2ess thanB> !ore than(> E'ual toD> 2ess than or more than

E3IFE3IFEE403.15 19?. :hich o% the$rimary and secondary loo$ e'uations o% a trans%ormer are correctG2 2 22 11 11) R I E V and R I E V # + = + =2 2 2 2 1 1 1 1) Z I E V and Z I E V % + = + =2 2 2 2 1 1 1 1) Z I E V and Z I E V & = + =02 2 2 2 01 1 1 1) Z I E V and Z I E V ' = + =E3IFE3IFEE403.15 200re'uently asked 'uestions:B. Dra4 the vector diagrams o% a trans%ormer considering &oth 4inding resistances and leakage %luDes %or the %ollo4ing loads.A> .esistive loadB> Inductive load(> (a$acitive load:hat are the salient $oints o&served in each caseGEE403.15 218>. A ??HA 88,,688,, -,1I single $hase trans%ormer has the %ollo4ing $arameters.BJ8.+ ohmsK LBJ9 ohmsK .8J,.,? ohmsK L8J,.,A ohmsa>0ind the $rimary resistance and leakage reactance re%erred to secondary&>0ind the secondary resistance and leakage reactance re%erred to $rimaryc>0ind the e'uivalent resistance and leakage reactance re%erred to i> $rimary and ii> secondaryEE403.15 22Thank youThank you