All these comments criticising this video is somewhat right but as the ma'am said there is a catch so she meant that there is an exception and it is giving pulse D.C. to a pulse transformer and one more point to all my commentators - yes a pulse D.C exists . if u don't believe then go and google it. so we conclude that- 1. heading of this video is totally correct 2. Information given in this video is totally true because if it is wrong , then i would not be able to charge my mobile in train and could not comment. 3. Dear cameraman please focus on the circuits made by ma'am rather than her face because we are here to learn something from her not to see her face. 4. ma'am keep uploading ur videos we are here to learn and grow.
Dc is dc because it's not pulsating They using converters U are directly ignoring basics DC generates a standard magnetic field Some may be criticize because they know dc convert. Transformer to a magnet But still some people there don't understand few things they may thought dc can run transformer They may lose marks bcoz of these Just my point of view
Dont say it is DC...you may call it as pulsed DC or Half sine wave which has frequency component in it. Hence, it still obeys faraday's law (time varying flux requires frequency component in it)....Pure DC does not have frequency component, will not work and burn after some time. Use correct terms in your title.
I can also take the output of a Variable Frequency Drive (VFD) and feed it into an induction transformer and have it work the same. The output of a VFD is a Pulse Width Modulated DC voltage, that can be made to imitate an AC signal.
Please do not pollute the fundamental principles of physics by saying transformers will work on DC. Leave the topic of pulse transformers for power engineers only. These types of things occur when engineers are recruited as teachers where the fundamental concept gets lost and students gets confused.
you are absolutely wrong sir. we have to teach him fundamental principle as well as this principle. then only stuent will start thinking and approach the teacher and start asking the doubts or start searching in internet.
I am very happy that you teached very nice practical concept which is very less explained in day today classes. You explain the pwm hft concept of smps.great ma'am.
Good to hear that dear, but confirm with an expert once whether what you think is right or wrong. Otherwise, ...... , let me not say. You know it better.😊 On a lighter note: 😊😊 The purpose of this video is to bust the myths you have. If you still want to be in the same myth, sure carry on.
Who in this entire multiverse taught you that an pulsating signal is DC. And if we could make a transformer which is working on DC why aren't we not using in transmitting electrical energy hence DC has less power loss comparing AC.
AC power can be stepped up or down by windings to limit transmission loses due to resistance loses in the wire by Power Lose = Voltage*Current = Wire resistance * (Current)^2. This is why long transmission lines are high voltage.
@@antonsv2195 You are exactly correct but that lady in that video tells DC power can be used to make a transformer work. If they could step up and step down DC power everyone would be gone for DC power.
Pulsating waveforms that are unipolar (of either only positive or negative polarity) usually are treated as dc signals. The video clearly states that transformers won't work with steady DC but only pulsating dc signals. Also HVDC transmission is a very real thing. We can increase or decrease dc voltages pretty conveniently using power electronic converters but are usually restricted to low power applications, typically from around a few watts in your cellphone chargers to about 100kW in electric vehicle fast chargers.
When you rectified AC u get pulsating DC....it works on specially designed pulse transformer. She is taking abt pulsating transformer but for views she has given wrong TITLE.
Dear sir/ mam I got some question in my mind .. i tried every where search on net .. but dint get.. plz help Q1) how to find any capacitor value of any single phase motor with the help of Given data *winding value resistance Voltage RLA current SPEED MULTY OR SINGLE RPM WATT Q2) And also how to knw abt watts /HP / KW ... with help of motor resistance any single phase or 3 phase Because on field we face lott of issue with Motor name plate... missing
connect motor to supply, if there is any capacitor on yhe motor than connect to 1 phase otherwise in case of 3 phase motor connect to 440 volt supply and measure the current of motor in case of three phase motor current will be ~1.5 times of rated HP of motor. Now you can calculate the HP of motor without its nameplate
@@udhayarajan_m Yes that is how it was done earlier. But it has a serious drawback: The size and weight of the transformer. If you use a transformer to step down 220V 50Hz AC to a lower value in the first stage, the size of the transfomer will be very large. Nowadays what is done is that the 220V AC is rectified direclty to produce close to 300V DC and then this DC voltage is chopped using semiconductor swtiches at very high frequencies (tens of kilohertz). As the working frequency of the transformer increases, we can decrease the size and weight of the transformer. Hence this high freqency pulse train in fed to the pulse transfomer which is smaller in size to step down the voltage. An output rectifier along with filter caps help smooth out the pulsating waveform at the output of the transfomer to produce the required DC voltage. Most such circuits are regulated circuits ie, they maintain the value of the output constant in normal operating conditions through feedback.
nice explanation........cell phone charger is basically a "SMPS".after rectification of "AC to DC" the DC is fed to a high frequency switch which works by "PWM TECHNIQUE" after this it is connected to a "transformer" and the out of transformer is again connected to next stage rectifier THERE WE GET 5V ...........There should be a rectifier unless its "HIGH FREQUENCY SWITCHED SUPPLY" ...
Here if you applied dc.. (1). Ideal transformer ( only coil) (2). Practical Transformer ( coil with resistance). (1).Then Vl = L * di/dt =Vdc... From there we can calculate I(t) =( Vdc/L) * t... That means if we provide dc then current will increase and due to this the transformer core will go into deep saturation since flux is increasing. But constant voltage will induced in primary side as well as secondary side. (2). For practical case if we do transient analysis of RL ckt. then we will get I(t) =( Vdc/L) *(1-e^t/tau)... During transient period it will give time varrying induced emf in primary nd secondary side. But at steady state there will be no induced emf as flux become constant at steady state. So... Ideal transformer induced voltage under DC condition will be constant voltage but practical transformer at steady state there will be no induced emf. In case of pulse transformer whatever discusses it is right.
Dear Firstly even the positive pulse waveform cannot be applied directly to the transformer, else transformer will saturate. All that is required for the transformer is the volt sec balance should satisfy across the primary winding, i.e. average value should be zero , so that flux resetting happens. and why you shown transformer output as DC, there is a converter phase in between which does that. Please be precise while delivering such lectures.
Thanks for making it really clear but I do have a very weird doubt. This doubt may be weird and I am sorry if it seems like a meaningless one , The voltage induced is L di/dt , where di/dt is instantaneous change in current. Since pulses are obviously generated in time intervals does the output of the transformer also comes out to be in a pulsed form ? And if yes , how is it converted into continuous DC
Dear mam, I want to note that winding will be only damaged when you give rated dc to primary winding. If this voltage is less than rated dc, windings can sustain that voltage.
DC voltage less that rated can still damage the transformer. The dc voltage needs to be very low such that only rated current flows though the transformer. Such a dc voltage may be in the range of only a few volts or even tens of volts for most transformers.
In presence of dc current the inductive windings in primary coil is treated as short circuit More current will flow more power in form of heat will dissipate and boom your transformer is on fire
all rectifier circuits dont need transformer. u can see a chinese serial bulbs (adapter)working without a transformer!! for low power applications transformer is not necessary
Thank you for well scripted lecture.... we need to question the existence of all rules and terminologies......these rules r being made to question the boundaries .... all d best keep up the good teaching spirits
"we need to question the existence of all rules" There is no WE. Be sure to question THIS presentation while you are at it. Maybe there's an answer among the questions.
Madam you have said that you can open your cellphone. I just opened now but now it's not working and I can't know how to fix it I can't see any transformer in my cellphone
You said that AC will get converted into DC bcoz of rectifier but also our one terminal is of DC so what if we give directly DC then will it ignore the rectifier part??? What will happen if DC will get through rectifier for going ahead???
Dc voltage applied to a transformer will initially make it an open circuit and later on as the time progresses the current develops and increases gradually as per time constant L/R and attains it's maximum value after certain time and then it's behaves as short circuit and draws heavy current from supply mains and get damaged. In pulsed Dc the time constant of the circuit is making the delay in current increment rate and once the pulse downs to zero the decrement in current starts this pulses are making the current not to attain it's maximum value and time constant of the circuits is making gradual increase in its value.
All these comments criticising this video is somewhat right but as the ma'am said there is a catch so she meant that there is an exception and it is giving pulse D.C. to a pulse transformer and one more point to all my commentators - yes a pulse D.C exists . if u don't believe then go and google it. so we conclude that-
1. heading of this video is totally correct
2. Information given in this video is totally true because if it is wrong , then i would not be able to charge my mobile in train and could not comment.
3. Dear cameraman please focus on the circuits made by ma'am rather than her face because we are here to learn something from her not to see her face.
4. ma'am keep uploading ur videos we are here to learn and grow.
nikhil singh
@@dharmrajpatel4057 yaa bro?
ruclips.net/video/WNRzU5DLA0I/видео.html
www.quora.com/Charging-points-in-Indian-trains-are-110V-D-C-but-my-mobile-charger-and-laptop-charger-needs-110-V-A-C-Still-both-the-chargers-are-working-properly-How-is-it-possible
Dc is dc because it's not pulsating
They using converters
U are directly ignoring basics
DC generates a standard magnetic field
Some may be criticize because they know dc convert. Transformer to a magnet
But still some people there don't understand few things they may thought dc can run transformer
They may lose marks bcoz of these
Just my point of view
her friendly up beat teaching style is very refreshing i dont think i would start to drift off to sleep in her class
Dont say it is DC...you may call it as pulsed DC or Half sine wave which has frequency component in it. Hence, it still obeys faraday's law (time varying flux requires frequency component in it)....Pure DC does not have frequency component, will not work and burn after some time. Use correct terms in your title.
I think she is dumb. Who is she ? Teaching wrong information.
Fluctuating voltage*
Really, she has lack of practical knowledge.
I understand perfectly thanks lot this question confusing since from 3yrs when I travelling in train once again tq madam
Madam incomplete information is injurious to health .
Don't make fool to the students
Glt explanation diya he
Galat to Nahi kah shakte ,
Incomplete word better Hoga use karna
Thanks for clearing my doubt, the video was very informative. And yes I'll not forget to mention that you got really beautiful smile.
I can also take the output of a Variable Frequency Drive (VFD) and feed it into an induction transformer and have it work the same. The output of a VFD is a Pulse Width Modulated DC voltage, that can be made to imitate an AC signal.
THANK YOU that was VERY well explained and makes SENSE! GREAT job!
Please do not pollute the fundamental principles of physics by saying transformers will work on DC. Leave the topic of pulse transformers for power engineers only. These types of things occur when engineers are recruited as teachers where the fundamental concept gets lost and students gets confused.
she should have told about the SMPS.
you are absolutely wrong sir. we have to teach him fundamental principle as well as this principle. then only stuent will start thinking and approach the teacher and start asking the doubts or start searching in internet.
Before every conclusion.... There are a lot of wrong concept..
@@sadmadkab This shows how good you are at the subject. Donot put our students at shame in front of the world .
I am very happy that you teached very nice practical concept which is very less explained in day today classes. You explain the pwm hft concept of smps.great ma'am.
Nice video mam. The intention u have to let us know such tricky questions is really great. Go ahead
Pulse is not dc , it also time varing V or i that means it AC , i think
Good to hear that dear, but confirm with an expert once whether what you think is right or wrong. Otherwise, ...... , let me not say. You know it better.😊
On a lighter note: 😊😊
The purpose of this video is to bust the myths you have. If you still want to be in the same myth, sure carry on.
Who in this entire multiverse taught you that an pulsating signal is DC. And if we could make a transformer which is working on DC why aren't we not using in transmitting electrical energy hence DC has less power loss comparing AC.
Nice questions
AC power can be stepped up or down by windings to limit transmission loses due to resistance loses in the wire by Power Lose = Voltage*Current = Wire resistance * (Current)^2.
This is why long transmission lines are high voltage.
@@antonsv2195 You are exactly correct but that lady in that video tells DC power can be used to make a transformer work. If they could step up and step down DC power everyone would be gone for DC power.
Pulsating waveforms that are unipolar (of either only positive or negative polarity) usually are treated as dc signals. The video clearly states that transformers won't work with steady DC but only pulsating dc signals. Also HVDC transmission is a very real thing. We can increase or decrease dc voltages pretty conveniently using power electronic converters but are usually restricted to low power applications, typically from around a few watts in your cellphone chargers to about 100kW in electric vehicle fast chargers.
When you rectified AC u get pulsating DC....it works on specially designed pulse transformer.
She is taking abt pulsating transformer but for views she has given wrong TITLE.
Thank You So Much Ma'am I Got My Doubt Clarified Which Was A Doubt For Years ..
Thank you mam...very well explained..bhaut dino se doubt tha..clear hogaya...🤗🤗
Better use the word SMPS technology if u face this kind of question in interview
Very interesting topic..I was really like this video
Very corect what you are saying - thanks for a corect course of electrical engineering
Dear sir/ mam
I got some question in my mind .. i tried every where search on net .. but dint get.. plz help
Q1) how to find any capacitor value of any single phase motor with the help of
Given data
*winding value resistance
Voltage
RLA current
SPEED MULTY OR SINGLE
RPM
WATT
Q2) And also how to knw abt watts /HP / KW ... with help of motor resistance any single phase or 3 phase
Because on field we face lott of issue with Motor name plate... missing
calculation is there for specific torque output. follow that type numerical
1 you can get from P.S. bhimra generalized theory of machine
connect motor to supply, if there is any capacitor on yhe motor than connect to 1 phase otherwise in case of 3 phase motor connect to 440 volt supply and measure the current of motor in case of three phase motor current will be ~1.5 times of rated HP of motor. Now you can calculate the HP of motor without its nameplate
the way of teaching and writing is excellent....
Nicely explain.....well done
ruclips.net/video/ygzss6mYlZs/видео.html
Ah!!❤️ Snehalika Maam!! Is love❤️😌😍😌
I always watch your videos for the last almost 2 years but this is first time ever I'm doing comment on your upload!. Best wishes!
Very informative
👌👍👍
Way of teaching is good
Nice info mam..thanks ...nd ur looking so attractive during the teaching
How that last stage transformer giving DC of 5V????
Same doubt First there should be a transformer then only retifiers are placed,Am I right?
Induced current is only in one direction
@@udhayarajan_m Yes that is how it was done earlier. But it has a serious drawback: The size and weight of the transformer. If you use a transformer to step down 220V 50Hz AC to a lower value in the first stage, the size of the transfomer will be very large. Nowadays what is done is that the 220V AC is rectified direclty to produce close to 300V DC and then this DC voltage is chopped using semiconductor swtiches at very high frequencies (tens of kilohertz). As the working frequency of the transformer increases, we can decrease the size and weight of the transformer. Hence this high freqency pulse train in fed to the pulse transfomer which is smaller in size to step down the voltage. An output rectifier along with filter caps help smooth out the pulsating waveform at the output of the transfomer to produce the required DC voltage. Most such circuits are regulated circuits ie, they maintain the value of the output constant in normal operating conditions through feedback.
By vtg regulator ic
@@manjunathvishnumoorthy7479 Thanks u VERY MUCH 😊😊😊 FOR information
Great video.....get good knowledge of the basic topics
Your way of teaching is very good and ur smile omg ,i falling to you.
Nice explanation please make vedio on pulse DC transformer, Thanks.
Today you clear the my doubts,thank you
inverting and non inverting ABOUT one video plz madam
Excellent video. I have a question to you Madam. Is the automotive ignition coil a pulse type transformer?
Bingo, you are absolutely correct 😍
nice explanation........cell phone charger is basically a "SMPS".after rectification of "AC to DC" the DC is fed to a high frequency switch which works by "PWM TECHNIQUE" after this it is connected to a "transformer" and the out of transformer is again connected to next stage rectifier THERE WE GET 5V ...........There should be a rectifier unless its "HIGH FREQUENCY SWITCHED SUPPLY" ...
Rectified dc given to high frequency switch(transistor or mosfet) and this output fed to transformer
Here if you applied dc.. (1). Ideal transformer ( only coil) (2). Practical Transformer ( coil with resistance).
(1).Then Vl = L * di/dt =Vdc... From there we can calculate I(t) =( Vdc/L) * t... That means if we provide dc then current will increase and due to this the transformer core will go into deep saturation since flux is increasing. But constant voltage will induced in primary side as well as secondary side.
(2). For practical case if we do transient analysis of RL ckt. then we will get I(t) =( Vdc/L) *(1-e^t/tau)... During transient period it will give time varrying induced emf in primary nd secondary side. But at steady state there will be no induced emf as flux become constant at steady state.
So... Ideal transformer induced voltage under DC condition will be constant voltage but practical transformer at steady state there will be no induced emf.
In case of pulse transformer whatever discusses it is right.
Aap mujhe bahut pasand aaye accha video tha explain accha kiye,😍
Can we use thyristor for pulse dc??
I like your teaching style
Thanks, Mam.
It was really confusing question. Now i have clear concept about it.....
Ur voice is crystal clear.
Thank u for every thing this channel made me clear my Meo class 4
Really? What question surveyor asked??
What question surveyor asked? This video came yesterday only..??
Dear Firstly even the positive pulse waveform cannot be applied directly to the transformer, else transformer will saturate. All that is required for the transformer is the volt sec balance should satisfy across the primary winding, i.e. average value should be zero , so that flux resetting happens. and why you shown transformer output as DC, there is a converter phase in between which does that. Please be precise while delivering such lectures.
Excellent...
Aripichav anna.
Pulse dc is not pure dc, it is different, pulse dc means mixed with dc
Have a look at this NCS thotakura shekar
But in our no where it is mentioned that it is dc voltage. It gets only 100-240V ac.
Thanks mam . Way of explanation is very interesting.
Thanks for making it really clear but I do have a very weird doubt.
This doubt may be weird and I am sorry if it seems like a meaningless one ,
The voltage induced is L di/dt , where di/dt is instantaneous change in current.
Since pulses are obviously generated in time intervals does the output of the transformer also comes out to be in a pulsed form ? And if yes , how is it converted into continuous DC
Same pulse in output too. We HV to use a rectifier again in output stage ie; Schottky diode or a fast recovery diode to get pulse less dc.
Yes of course. The transformer output will be AC. The pulse shape depends on several factors.
I did not understand how the puls transformers works. The rest was very good. Thanks.
We understand it English
Please more videos
Thanks a lot
Good way to explain mem so plz continue to make complete series of electrical machines
Through snehalika mam I thoroughly understood the meaning of "lovable education".😊 😍
Particularly in 10:10.😘😘😘😘😘
"EDUCATE WITH LOVE"😃😃😃😃
One small question if transformer winding damages for DC supply then how can we use DC in rotor of synchronous machine
Mam really mja aa gya plz aise topic post karte rhiyega
Excellent described.Thanks
Well explained... Keep sharing...
Fantastic inputs.
Dear mam,
I want to note that winding will be only damaged when you give rated dc to primary winding. If this voltage is less than rated dc, windings can sustain that voltage.
K N Rao jindabad
DC voltage less that rated can still damage the transformer. The dc voltage needs to be very low such that only rated current flows though the transformer. Such a dc voltage may be in the range of only a few volts or even tens of volts for most transformers.
In presence of dc current the inductive windings in primary coil is treated as short circuit
More current will flow more power in form of heat will dissipate and boom your transformer is on fire
It is also the case that DC will saturate the core and the AC component will cease going *through* the transformer.
Nicely explained
Thank you
Camera man,please don't shoot her face by zooming we can't see the back circuit diagram
Ull get short circuit ed if u see that
🤣🤣🤣
Yours all of videos are very interesting, Shekhar sir also teach very good.
In charger circuit you have drawn rectifier block so question is that rectifier also have transformer how it will works on dc ?
all rectifier circuits dont need transformer. u can see a chinese serial bulbs (adapter)working without a transformer!! for low power applications transformer is not necessary
you have cleared my 15 years old question
zulfiquar ali .....મુ
Mam yyyyy the AC supply used in 🚆 trains?????
Good teaching method...but how come the flux reversals is archived
So nice of you and for your kind information I tell you , this is not a dc it is a smooth dc or puls ok
Whare is feed bake CKT and comparitor and pulse generator or freqency genrator
Great video. Thank you ma'am!
Sir stepped core in transformer means
Thank you for well scripted lecture.... we need to question the existence of all rules and terminologies......these rules r being made to question the boundaries .... all d best keep up the good teaching spirits
"we need to question the existence of all rules"
There is no WE.
Be sure to question THIS presentation while you are at it.
Maybe there's an answer among the questions.
Thanks a lot for this very much usefull information..
Good explanation .
Hi madam, nice info video, can u tell which pulse transformer is used in mobile charger. There are two type of pulse transformer is there.
Thank you ma'am for sharing this
Excellent explanation.
Whether pulse and flyback transformers are same?
Beautifully explained...
Nice information ma'am
Thank you
Dear....mam please explain about power factor
Then y don't we use dc in Transmission and impulse transformer
By this concept is it possible to produce RMF?
Yes in transmission dc voltage only flowing to reduce the losses,high voltage less current
Transmitting DC will cost more
But less losses
@@khabyofficial49 Setup cost is more in dc while operational cost is considerably less
Nice vedio and very useful
ruclips.net/video/ygzss6mYlZs/видео.html
If you give pulse dc to transformer... output of transformer will be a pulse dc...then how can we get a pure dc to our mobile phones....
May be by equipping rectifiers at cell phone end
Yes how mam please tell us
Switching components like diode or MOSFET s are using secondary of tf
@@malleshd4763could you pls tell me the function of diode....
@@VinayKumar-po4zo u r not like my answer I got it k ,diode can convert bidirectional waveform into uni directional waveform.
So Nice of you...
Kuch samajh nahi aaya per sun kar bahut achha lga
Mam led tube light driver has sm transformer works on dc is it pulse transformer
Please explain Telugu Aldo. It is useful to others like iti and diploma students.
u got a new subscriber here..
Thanx mam ... for this special session...
On special pulse transformer ....😎🤟
Thanks.its very useful.
It's really very Interesting.. Thank you mam 😊
would the dc output from transformer be harmonic free?
Amazing... Excellent one... Mind blowing explanation
What about the converter In the charger?
Great work! Keep it Up!
Madam you have said that you can open your cellphone. I just opened now but now it's not working and I can't know how to fix it I can't see any transformer in my cellphone
Reply please mam
change your topic to "How transformer works on Pulsated DC".
may be she is talking about chopper transformer which is design for high frequency, and she called it pi-transformer.
Firstly, I would like to say you have a beautiful voice.
Okay, now to the point- "WHAT WAS THIS VIDEO? " 🤔
Call me medam thamil 9524420027
@@ganeshganesh7583 Hatt vc
ruclips.net/video/ygzss6mYlZs/видео.html
Mam please make a video for magnetising current test in txf
What the need of pulse tra. In charger..? I mean we can make ckt with normal tra also..
This is an. Informative video.. Thank you
ruclips.net/video/ygzss6mYlZs/видео.html
Hey can you please explain why power dissipation may be considered in transistor for any project
You said that AC will get converted into DC bcoz of rectifier but also our one terminal is of DC so what if we give directly DC then will it ignore the rectifier part??? What will happen if DC will get through rectifier for going ahead???
Do the output be pulsating or fixed.if it is pulsating then why? Do fixed dc is not capable to charge
Pulsating get,by using switching components fixed dc will get
Dc voltage applied to a transformer will initially make it an open circuit and later on as the time progresses the current develops and increases gradually as per time constant L/R and attains it's maximum value after certain time and then it's behaves as short circuit and draws heavy current from supply mains and get damaged.
In pulsed Dc the time constant of the circuit is making the delay in current increment rate and once the pulse downs to zero the decrement in current starts this pulses are making the current not to attain it's maximum value and time constant of the circuits is making gradual increase in its value.
How we got same o/p(5v) 240v ac or 110 v dc
How large your transformer core area ?