# EMF Equation of Transformer – Single Phase Transformer – Basic Electrical Engineering – First Year Hello friends in this video we are going to see and develop EMF equation of a transformer so we have seen working principle of a transformer you have got induced because of mutual induction and what is the concept band is is Faraday’s law of electromagnetic induction so let’s proceed so I am having a flux waveform like this a sinusoidally varying flux waveform I will get because I am applying AC voltage this is a maximum value of flux phi 0 pi 2 pi the equation of this waveform is Phi equal to Phi M sine Omega T now this flux waveform is changing with respect to time hence by Faraday’s law of electromagnetic induction EMF induced II equal to if I am considering windings have n number of tons and D Phi by DT but hold on this is just a magnitude Rho of e what about the direction what they mean by direction along with the Faraday’s law of electromagnetic induction one more law was there that is Lenz’s law what it says if voltage V is given I throw can I because of which flux waveform or flux is getting produced if this flux which is changing with respect to time linked with n number of tons EMF will get induced such a way that it will oppose the current which has produced the first five so by Lenz’s law this EMF e should be minus and D Phi by DT this is a generalized expression we are talking in terms of primary number of terms secondary number of terms with respect to transform one so that I can write over here EMF induced at the primary side II won equal to minus n1 D Phi by DT where n1 is nothing but number of tons of primary winding so let’s substitute Phi equal to Phi M sine Omega T over here I will get e 1 equal to minus n1 D by DT of Phi M sine Omega T so if I take a derivative I will get minus n over 5 is a constant sine Omega T derivative is cos Omega T multiplied by Omega now this e 1 I can write like this and 1 for M Omega bracket minus cos Omega T I want to write the equation of a 1 in terms of standard science or equation so for that purpose this minus cos theta is replaced with sine theta minus 90 degree so theta means Omega T over here so e 1 equal to Phi M Omega is 2 pi F multiplied by n 1 and minus cos Omega T I can write sine Omega t minus 90 degree so this is a standard equation can be compared with even equal to e m1 sine Omega T plus Phi I will not use the value Phi because that we have already used for a flux so this will be this simple sir so if I compare I will get e m1 equal to 2 pi F into 5 into n1 and psy equal to minus 90 degree we are dealing with rms value so rms value of EMF equal to maximum value divided by root 2 so this is equal to 2 pi F into Phi M into n 1 divided by root 2 if you see carefully this 2 pi by root 2 is a constant if we solve that will be 4 point 4 4 so finally what I can say primary EMF induced RMS value is 4 point 4 4 Phi M into frequency into number of primary terms similarly secondary side EMF can be considered as four point four four five M into F into n 2 because that will depends only on secondary number of turns flux Phi will be same because EMF induced over here is because of mutual induction and we’ve got angle minus 90 degree with respect to flux waveform so minus 90 means it’s a lagging so I can write a statement P 1 and E 2 Lac flux Phi by 90 degree or PI by 2 radians so if you draw phasor diagram it will be like this reference is flux phi and EMF induced because of this fight is even at the primary site that will lag behind this phi by 90 degree similarly same flux Phi is linking with secondary winding hence EMF 2 will also lagging behind this Phi by 90 degree so here we have seen EMF equation of a transformer and that is given by for a primary side four point four four Phi M F into N 1 where N 1 is a primary number of turns e 2 four point four go Phi M into F into n 2 and the secondary number of turns see or here frequency F will remain same on both sides moreover this e 1 and E 2 lag behind satisfied by 90 degree thank you

### 62 thoughts on “EMF Equation of Transformer – Single Phase Transformer – Basic Electrical Engineering – First Year”

• October 26, 2016 at 8:39 pm

it was really very helpful thanku 🙏🙏

• December 13, 2016 at 5:02 am

• December 16, 2016 at 6:54 am

why the emf lags? to flux?

• February 8, 2017 at 4:25 pm

excellent  , thank you from Thailand.

• February 11, 2017 at 1:39 am

can get a video about classification of transformer…

• March 5, 2017 at 7:04 pm

very clear

• April 4, 2017 at 4:40 pm

sir please do one video of torque equation of dc motor.

• April 5, 2017 at 6:45 am

we can get simply emf equation by using form factor and rms value

• April 26, 2017 at 10:11 am

thank you sir ….

• May 7, 2017 at 2:16 am

Thanku Thanku Thanku sir

• May 9, 2017 at 11:30 am

maja aa gyaaa

• May 29, 2017 at 5:49 am

useful

• August 31, 2017 at 10:47 am

excellent work

• October 8, 2017 at 4:29 pm

make a video of measuring instrument,,,, 3phase induction machine,, single phase induction machine

• October 8, 2017 at 4:31 pm

sir make a video of poly-phase circuit

• November 26, 2017 at 7:28 am

Thanks sir

• December 15, 2017 at 5:33 pm

It was very helpful. Thank you sir

• January 29, 2018 at 6:31 pm

explanation was good but very slowly it should be better to hear your lecture videos in speed of 1.25 at youtube settings
and later all is fine

• February 20, 2018 at 1:36 pm

What is denoted by the Em1? And form where you get the equation e1=Em1sin(wt+¥)??

• March 10, 2018 at 6:46 am

Sir aap be omega Ki jagah 2πf. Kyun likha

• March 30, 2018 at 3:20 am

Konsa software use Krtey ho sir video k lyr

• April 3, 2018 at 5:32 pm

your way of explaining is far better
being in IIT also never seen any teacher explaining concepts in an easy way like your's
just there is a problem in hearing by headphone audiable through only left ear.

• April 9, 2018 at 12:24 pm

Sir hindi me chahiye

• April 9, 2018 at 12:25 pm

Please sir i want in hindi

• April 16, 2018 at 1:04 pm

doing foc.. anyone?

• April 25, 2018 at 8:02 pm

bahut sshi b…thnk u sir

• July 7, 2018 at 8:13 am

Thank u sir it's is very useful

• July 23, 2018 at 6:08 pm

I live in Pakistan how can i buy the whole course??

• July 28, 2018 at 11:54 am

Ekeeda is the best study channel this is very helpful for every student who learned electrical engineering

• October 3, 2018 at 5:16 pm

Your way of explaining is excellent sir
But a cute slowly

• October 27, 2018 at 12:49 pm

What happened to sin(wt-90)….I don't get that part….

• November 25, 2018 at 1:32 pm

i dont like this man what the fuck he teaching doesn't understand

• November 28, 2018 at 7:32 pm

Thanks a lot…it is a lot helpful to us . It just helped me during my exam time . Lastly thanks a lot to siluch kind of channel helping us out😘

• December 1, 2018 at 2:09 pm

Thank u soooo much for ur great 👍 explanation

• December 2, 2018 at 6:10 pm

Love u sir great explanation

• December 12, 2018 at 3:37 pm

Thank you very much sir……The easiest way to learn

• January 9, 2019 at 10:48 am

• January 14, 2019 at 6:08 pm

Understood very well. Thankyou sir.

• February 1, 2019 at 8:28 pm

Good explanation👌

• February 20, 2019 at 1:09 pm

Thnku sir its Really Helpful Great Job

• February 21, 2019 at 11:09 am

Why is transformer called constant flux machine?

• March 16, 2019 at 6:25 am

Sir aapne shayd galat btaya hai..E1 and E2 leads the flux by 90

• March 19, 2019 at 9:09 pm

Thank you

• May 4, 2019 at 9:29 am

Sir aap Hindi me padahiye kyuki apka english acha nhi hai (kindly request🙏😊)

• May 5, 2019 at 3:55 pm

Hindi me batao

• May 8, 2019 at 5:16 pm

https://youtu.be/RzUr6uJpAtA

• May 20, 2019 at 4:20 am

Sir aapke notes bhut achhe..he.. well done sir

• May 20, 2019 at 12:08 pm

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• May 20, 2019 at 7:08 pm

EMF EQUATION LATEST VIDEO 2019
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https://youtu.be/Ye_MPLX6YrM

• May 29, 2019 at 2:07 am

Supper

• May 29, 2019 at 6:38 pm

Gyus listen carefully…It is a gta sa car driving background sound in this video

• June 7, 2019 at 8:51 am

Why AC line tester glows at secondary side even after rectification and filtration in a centre tap transformer ?

How it can be fixed ?

• July 22, 2019 at 2:56 pm

Thanks sir

• July 22, 2019 at 2:57 pm

Sir clearly understand

• September 5, 2019 at 11:13 am

v.good vedos

• September 20, 2019 at 10:19 am

• September 23, 2019 at 12:54 pm

I love this channel..good examplination.. students who are watching this video please visit my channel and subscribe..

• October 16, 2019 at 9:35 am

Nice sir

• November 3, 2019 at 8:21 pm

thanks sir

• November 19, 2019 at 8:31 am

thanks sir

• November 24, 2019 at 6:32 pm
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