Rotating Magnetic Field & Synchronous Speed

[@zin360]

Wow, animation is the best method for teaching stuff like this. It is very hard to visualize this from the text for a beginner. Thanks for the video!

[@aamirmasoodabbasi9660]

thank you you summed it up in just 2:34 minutes

[@vrnshrma]

Thank you. It was quite hard to visualise this by just looking at the pictures in the book. Keep up the good work.

[@sandeshkhatri6846]

awesome video the engineering behind alternator is just amazing.

[@akaikangaroo]

So confusing yet so interesting!

[@bruno5601]

Okay, spend some do find this explanation, NEAT!

[@andrewdavis6191]

Great animation and description!

[@Chrazzari]

1:41 Finally found "the", it isn't missing

[@AJ-et3vf]

Awesome video! Thank you!

[@noseyknowsme]

Good video explaining rotating magnetic fields, but unfortunately your 3 phase waveforms are spaced 60 degrees apart not 120 degrees. One of the waveforms is 180 degrees out of phase.

[@SabinCivil]

They are placed 120 degree phase difference.

[@mickos19540]

Are You sure? bmtg.eu/data/pl/2.oferta/maszyny/budownictwo/pily_scienne_i_wiertnice_tractive/hf_czestotliwosc2.gif

[@nilshagness8055]

Learn Engineering It seams to me that you are wrong. I am teaching electrics in a technical college, and I have discussed this video with my colleges. Your diagram is not showing a three phase current with 120 degrees between the phases. Is a pity, because the rest of the video is great.

[@noseyknowsme]

You need to flip the red phase over (shift it 180 degrees)

[@SabinCivil]

Keith Evans Both the figures are right. You need not to compare with figures in text books. Thing logically. :)

[@akshaykapoor5679]

awesome work!

[@Carrierski]

Thank you so much for this.

[@belgicaYMario]

Thanks! very good explanation, all. Thanks!

[@SabinCivil]

Never, it will rotate at a speed slightly less than synchronous speed. The exact rotor speed will also depend upon load on the motor.

[@RahulPriyadarshi22]

Really helpful!

[@hunginh1202]

thanks you! I imagine 4 poles more difficultly than 2 poles.

[@thanos5432]

Can you explain why the stator's magnetic field frequency (synchronous freq) become smaller as the number of poles increases? Specifically fs = fe /2p. fs: synchronous freq fe: stator's voltages' freq 2p: number of poles per phase

[@chriscoleman2893]

kzbin.info/www/bejne/r6OsaYGsfa5niKc

[@MindTreeNexus]

Nicely described...thanks sir

[@angelacabyzhong8412]

Should the magnet polarity be reversed? I think the upper should be north and the bottom should be south by right hand rule.

[@jamelbrini-bb3kn]

Very nice

[@jacksonshaver809]

Nothing gets me going like a synchronous machine

[@Joshyfiji]

Thank you ! helped me so much :)

[@niklaskonberg8395]

I really like these videos, but the blue wire should be reversed and the red curve should be reversed also, since the currents sum will not be 0.

[@brianrios93]

Hey people, I have a doubt, in 2:00 it says that if you have more poles, the angular speed will decrease, but then, when you have 10 poles it says "magnetic field will rotate at this much angular velocity", and why? If you have more poles, velocity will decrease

[@motilalsuthar4048]

n=1/phi

[@brianrios93]

@@motilalsuthar4048 too late, at this time I forgot all about physics haha

[@DWattify]

Hey, I believe the North and South poles in your magnetic field diagrams are incorrectly labelled. They should be flipped

[@SabinCivil]

North and South poles are correctly marked.

[@DWattify]

Learn Engineering My bad, you are the master

[@sorestarbing3978]

Learn Engineering how about the rotating magnetic field of synchronous generator? as we know, for AC generator, rotor magnetic field (Br) produced from the rotor winding induces voltage in the stator winding. And this rotor magnetic field rotates because of the rotation of rotor. Could you please made a video of that. tq

[@nhungnguyen-wx3dm]

i hope somebody explain why poles correctly marked, i also think it should be flipped

[@nhungnguyen-wx3dm]

DWattify can you help me?

[@SirBalageG]

BME VIK elektrotechnika hozott ide

[@larobi998]

sok sikert a holnapi laborhoz :D én már túl vagyok rajta, nem lesz nehéz :)

[@solaimanhossain4933]

Why there are 10/12 poles in the induction motor? As we see from the equation. As the number of poles increases the synchronous speed decreases. Isn't it good if the number of poles stays minimum, As we're getting higher synchronous speed from it?

[@Dave_en]

As speed increases, torque decreases. Also higher the speed, more wear and tear of bearings. So speed is decided as per application. For water pump, maximum speed is required. For cooler, medium speed is required and for machinary which requires high torque and less rotation, low speed is needed. In case of ceiling fan, the speed is reduced for safety measures.

[@MrSculptedzoo]

Gyroscope 🥙 magnetic field?

[@hashiska.5358]

i think south and north poles are wrongly marked. correct me if i am wrong

[@WilsonPereira-um9gn]

Muito boa animação!

[@aerodynamico6427]

Baaco bachao!

[@shashankmore321]

In 2 pole winding i can see the net direction of the magnetic field. But in 4 pole winding what will be the direction of the net magnetic field?? I can only see the 4 pole rotate simultaneously but what will be the direction of net magnetic field created by adding the magnetic field of the 4 pole?

[@TankR]

The multi pole designs just mean there are, 2 N fields and 2 S fields for a 4 pole, 3N/S for a 6 pole, etc. Its just adding another coils per phase and splitting the separation in rotation. 1 coils per phase gives 3 coils placed 120 deg apart gives 2 poles 1N 1S, 2 coils per phase gives 6 coils total placed 60 deg apart (however, if you only look at, say the first coil of a given phase, they are still 120 deg apart. Its the second coils of the other phases that are 60 degrees either side of a given coil. imagine just taking another 1 coil per the 3 phases, flipping it over, and laying it back down perfectly offset, so phase 1 coil 1 is opposite phase 1 coil 2, and winding this flipped over copy so that coil 1 is N and coil 2 is S on the first half AC wave and flips for the second half. As the phases cycle with the AC current they create a N AND S pull on the rotor per phase as opposed to just the one field direction per cycle).

[@Integrelle]

Love the content, very good video, but man could there be worse grammar, the amount of "s" s missing hurts

[@marans5571]

How does magnetic field remain same when we have a sinusoidal current?

[@naveenearth2243]

How to calculate the speed of motor related to weight..

[@junaidqureshi8283]

Can u please explain how synchronous speed is promotional to no. of poles?

[@SabinCivil]

I hope its clear from video. Please watch it carefully :)

[@kreynolds1123]

First thing. Proportional, not promotional. Second thing: Proportional means a multiple, or is the product of. The equation for synchronous speed is (4 * pi * frequency) / (number of poles) . In this case, the more appropriate term to use would have been inversely proportional because its a dividend rather than a multiple of. The fact that you asked "how is how synchronous speed is promotional to no. of poles", and given the context that the video tells us what the equation is, but is short on why, makes me think you really want to know why, rather than what is the equation. It can be seen visually in the video, but the audio didn't cover it, so here goes. Say you have two poles. One full 360 degrees of rotation in the magnetic field might look like (North then South), and would take one full cycle of the electric field. But, if you have four poles, 360 degrees of of rotation in the magnetic field would look like (North South North South) thus require two full electrical cycles to complete. .

[@abdelhakimsaboundji1355]

Your 3 phase signal is fault... But thank you for your explanation!

[@devilliersduplessis7904]

The english needs some work but great video!

[@luigiionascu7056]

_yes your image_picture explication is good in realy __i knowledge rotating or translation field magnetic movie ellectron s and rotating or translation field ellectric creating or movie field magnetic__why?? i don t know ___archaicxn lord

[@naveenkumar-cj4ys]

what is reason it will not exceed synchronous speed??

[@MP-S-TG]

It actually can when working as a generator. In fact, it's always faster than the synchronous speed. As a motor, however, it will be always slower than that speed: The rotor in a motor rotates because of the relative speed between the magnetic field and itself. Thus, the rotor cannot operate at the magnetic field speed, cause there would not be any relative speed and, therefore, the magnetic field would not induce any EMF... So there would not be any current induced in the squirrel cage... So there would not be any torque... If the rotor reached the synchronous speed by any external means, then (as explaind above) the rotor would decrease its speed, reaching a stationary speed lower than the synchronous speed

[@Kevin-cy2dr]

How does magnetic field remain same when current varies?

[@marans5571]

yes i have the same question as well!

[@wiricelliams1442]

when current of one phase go down another get back up. total current remain constant. orientation changes ~~~ > rotating magnetic field

[@splodge69552]

so the speed of rotation can never be greater than synchronous speed in an induction machine?

[@kreynolds1123]

@splodge695523 "so the speed of rotation can never be greater than synchronous speed in an induction machine?" Depends on what you mean by speed of rotation. If your referring to the stator's magnetic field, its magnetic field speed of rotation IS the synchronous speed. On the other hand, if your referring the the rotor's rotation, then an induction machine has two modes of operation. One: as a motor where the rotor spins slower than then magnetic field because of load and or friction, and is described as having a positive slip. Secondly, the other mode of operation is as a generator where a prime mover spins the rotor faster than the magnetic field's rotation, and is described as having a negative slip. As a motor, an induction machine draws power from the grid, As a Generator it feeds power back to the grid.

[@tatvanishant8961]

Good explen but nat a 120 angal the 60 angal

[@militaryforces4441]

best

[@syedyaseen8719]

how 1-phase alternator works

[@HamzasaeedKhan]

I download the video and upload at my facebook page but you complain at me to facebook, kindly tell me the legal process of sharing this huge knowledge of electrical engineering as an electrical engineering student on facebook? I hope you will understand.

[@sachitapathak]

You can share youtube link of any video but downloading and uploading from other's id makes illegal 😉

[@nirbhaythacker6662]

Could've been explained better.

[@LuxySopMg]

Guys sorry.. i still don’t understand, which is the cause that make the magnetic field rotate? :s

[@TankR]

In a single coil, powered by AC, as current flows in one direction, ie the first half of the AC wave, a magnetic field will develop in one orientation, raises in strength then dips back down before reversing orientation as the AC crosses the zero point and completes the second half of the wave for a full cycle. If you were to rectify the AC wave thus only getting positive waves you would see the magnetic field maintain orientation as the strength bobs up and down (ignoring the inductor like effects that would oppose changes in voltage slightly), ie instead of N S N S the field orientation would be N N N N for each wave voltage 'hump'. The rectified bit isnt important, just hammering home how voltage and more importantly current direction determines field orientation. Now, if instead of a single phase of AC, we used 3 coils connected to 3 phases of AC, 120 degrees apart in rotation, then the N and S orientated fields would appear to 'rotate' around the stator. Its not physically rotating, per se. Its the magnetic field is being built, dipping, and flipping in time with the current in each given phase. It simply appears to 'slide' across which ever coil is in the N or S orientation based on the direction of the phase current in the coil, effectively dragging the field flux density along for the ride. The multi pole designs imply instead of using 3 coils (one per phase, each coil covering 120 degrees of the rotors circumference, or 120 degrees apart in rotation) youd use 6 (2 per phase, 60 degrees apart in rotation) for a 4 pole motor, or 9 coils (3 per phase, 30deg apart) for 6 pole, etc.They then overlap the coils with a slight offset for various magnetic field motive force voodoo reasons (Look at the motor casing in the last bit, see how the coils seem to come out of one runner, cross a few, then go down another? They also share runners with other coils, in a specific sequence which maintain the smoothly 'sliding' or 'rotating' magnetic field peaks).

[@ForcefighterX2]

Amp up the voltage, rotate the fields very fast and you built yourself a first class electrogravitic engine (aka "anti gravity"). Just don't tell anyone or some nice men will come visit you. The last part was no joke - do some research and you will find it has happened before (outside of the Matrix of course).

[@filipkavcic664]

voltage has nothing to do with the speed od rotation. only frequency of aplied voltage

[@TankR]

You mean like how they levitated that frog? Yeah, thats not how that worked, son. Why dont you 'do some research' into the university experiment that achieved the levitating frog? Or is that too much reality for your brain to cope with? Or by 'do some research', do you mean go to those parts of the internet where schizophrenics make shit up to feel special? Because, yeah most of them are just making shit up to feel special, and need to take their meds. The rest of them just need to stop making shit up and take a physics class. Those nice men arent from the government, they're from the psyche ward. You can tell by the coat color. Black = government, blue or white = psyche ward. And before you lay into me with your insults (because if there is one thing the truth needs to be believed is being belittled into accepting it. Fuck math!) or vane attempt at appearing blase about having your headcanon shot down (like cool guys not looking at explosions, not addressing your rehashed conspiracy theory being blown apart is cool, right?), please, do explain how this high energy rotating magnetic field negates mass, and how that magically does not create eddy currents in the matter the mass is made of? Better yet, explain to the class how space time curvature causes mass to gather at a central point in the first place. If you do the latter, when you're done, you can call the Nobel committee, they'll have some money for you! Now, wow us with your theories on over unity devices that be definition would mean if one would place a bar on a rotor in an over unity configuration sitting on the bar would cause it to throw you through the ceiling....you know, since it is creating more energy than your mass is putting into the system therefore opposing said mass with more force than it can apply....BTW, if that sounds silly, congratulations, you understand why overunity isnt a thing.

[@박푸랭]

there is something wrong. 3phase waveforms are spaced 60 degrees apart not 120 degrees.

[@sashatallyse539]

Coolasf

[@Divine91147]

rainbow

[@cichildtinfoil1743]

Nikola tesla was very good