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Here I try to show you the actual magnetic fields rotating by 3 phase AC.
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By: Mehdi Sadaghdar

Hi today, i want to actually try and show you the rotating magnetic fields in an ac motor like this. This is an actual clip from the end of my video, where i was able to successfully visualize the rotating fields. Is there anything because seeing is believing? I could throw theories and equations at you, but when you see it, you know that's why i got this power supply thanks to circuit specialists who, provided it make sure to check them out for a ton of parts and equipment. This baby can do from 0 to 400 volt dc or 300 volt rms ac up to 3 amps, and it does a bunch of critical measurements too, and it's loud it does between 45 to 1000 hertz and makes different waveforms too, and the output is somewhere on The back right and it's pretty sturdy 32, for when you throw your power supplies, you must always remember to turn off the high voltage supply output before fiddling with the output, and that's not the only thing i got.

I also bought this piece of sheet. That is a magnetic field. Visualization sheet see. If i place a magnet under this sheet, you can see the magnetic fields.

The black areas are the north and south poles, and the white line between them is where one pole transitions to the other. Now, to create the rotating magnetic fields in a three-phase ac, motor or brushless dc motor, which is basically a three-phase ac motor. We need three phases: each phase 120 degrees apart. Soft circuit specialists send me these three babies that i can stack and when they are connected properly well, they sound like a starship, but they also provide three phases.

Oh my god. So now we dismantle our motor to see the coil arrangements and we wrap the piece of sheet around the coils and with the three phases connected, we turn on the power supply and oh the over current protection tripped. I guess the coil is like a short circuit. So i lowered the voltage to avoid over current, really a short circuit eh.

I have an idea, i put 10 ohm resistors series with each line that will limit the current. So now i can run it from a higher voltage like 20 volts and that will send around 2 amps of sine wave into each line. Now, if we look at the sheets, well, that's underwhelming! Oh i know. Maybe the 45 hertz is still too fast to see with eyes.

Maybe i can do a slow-mo with my phone here. We go yeah, nothing is moving. Is there i put all these together and i still wasn't able to get any visuals? Why the hell? Oh now it's on fire, the resistors get super hot. Now, how would you believe in rotating magnetic fields see we need three electromagnets for three phases and on the surface of each one it looks like an alternating north and south, and we know this piece of sheet shows solid, dark for both north and south and doesn't Blink so having this sheath on the surface of electromagnets, looks like you have fixed magnets in space only further in air when the magnetic fields mix or when they combine inside the metal to create eddy currents is where you have rotating fields.

Unfortunately, if i put this sheet further away, the fields become too weak to make an impression on this magnetic sheet. I would have to have much stronger magnetic fields that my power supplies can't handle like 100 amps. Through these coils, i even tried to wrap my rotor stature in thick amounts of aluminum foil, but see there. It still shows up solid, i think, because the combined eddy current created in it may not be strong enough to make an appearance and be visible.

I even try to put a piece of steel on the stator, but still just shorts out the magnetic fields, but i'm sure the rotating fields are there. Let's just snap the rotor back on the motor, i should be able to run this motor at 45 hertz there. You go, although it's a synchronous, motor and needs proper communication and won't work right at a fixed frequency, see if i run it at a higher frequency, it gets stuck and such, but anyway, as the fields of the three phases rotate, it turns the rotors permanent magnets Stupid resistors, which reminds me: do you remember this failure of an induction motor i made a while back, but wasn't able to turn it now with the proper power supply. I should be able to turn it.

Of course, an induction motor doesn't have permanent magnets. It is the changing fields from the coils that create eddy current inside the metal body of the rotor that creates its own magnetic field that is pushed around by the rotating field. This is an asynchronous motor that doesn't need commutation like this. I have a copper pipe here that if i move a magnet beside it, i can move it around it's freely.

Turning, let's run it at 45 hertz. Oh, it wants to turn 45 hertz might be too slow. Here goes 300 hertz! Oh! Oh! Oh look at that. My motor is turning finally and, of course, at higher frequencies, we create greater eddy currents in the rotor.

That's why it's turning easier nice, so the rotating fields are real and, of course, to flip the rotation in these motors. All you need to do is to flip the connection of two phases. Only there now tesla would be really proud. Well, i failed to show you the actual rotating magnetic fields there might be a way, but for now i have an idea to show you the concept using led lights.

I connect three leds and resistors in a y configuration like this connect three phases and neutral at the center and when the led lights mix, you shall believe. Of course, the leds only turn on in the positive cycle of their phases, going full bright and back dim and turn off. So you can assume the bright cycle is north and the dark cycle is the south of the magnetic fields. Here are the leds: let's turn them on, yes, but actually, no, i think it's blinking too fast.

I have to do a slow-mo here we are wow. Now you can clearly see the rotating pattern of lights, a mixture of three sine waves of light and that's similar to how magnetic fields mix and create a magnetic flow that can move and rotate things. And if we flip the connections between the two phases. Now the magnetic fields flow in reverse.

I hope you finally believe in the rotating fields, beyond the theories and formulas not like this information was blocking your way to salvation or anything, but i personally learn better when i can imagine things in my head and again thanks to circuit specialists for providing these babies High voltage supplies are always welcome and thank you for watching pay.

15 thoughts on “Trying to see rotating magnetic fields”
  1. Avataaar/Circle Created with python_avatars Pexi The Builder says:

    I'm doing something wrong, I rarely get smoke out of my electronics? They just get hot and stop working. Maybe I need bigger power supply?

  2. Avataaar/Circle Created with python_avatars Just1ofGod says:

    Another great video can't wait for the next one but I guess I will.

  3. Avataaar/Circle Created with python_avatars Ryan Jardina says:

    There are LEDs with two pins that have two colors. If you reverse the polarity on the LEDs it switches the colors. Most places online call them "dual color LEDs". Probably would have looked pretty cool. In a WYE with no center. Wish I could have sent you some.

  4. Avataaar/Circle Created with python_avatars Bruce Weborg says:

    Hey come on , now you really really should get some installated alligator clips๐ŸŠ๐ŸŠ๐ŸŠthey're not that expensive ,๐Ÿ’ฐ๐Ÿ’ฒyou might be showing some youngsters ๐Ÿ‘จโ€๐Ÿ‘ฉโ€๐Ÿ‘งโ€๐Ÿ‘ฆ๐Ÿ‘จโ€๐Ÿ‘ฉโ€๐Ÿ‘งโ€๐Ÿ‘ฆthe wrong way ๐Ÿˆต๏ธ๐Ÿ“›๐Ÿดโ€โ˜ ๏ธ๐Ÿ‡ฏ๐Ÿ‡ต๐Ÿšซโ˜ขโ†ฉโ†ชโ†”๏ธโ†•๏ธ you really should not be doing this and somebody may get hurt really really badโ˜  anyway I still enjoy your show I really don't like seeing you get zapped๐Ÿ˜ด๐Ÿ˜œ๐Ÿ˜›๐Ÿ˜œ๐Ÿคช๐Ÿ˜๐Ÿคฏโ›‘ anyway PS Happy Thanksgiving if you celebrate Merry Christmas but I don't know if you do may your God bless you

  5. Avataaar/Circle Created with python_avatars Keith Sherry says:

    So now you've done the motor mehdimation, you need to do a… FULL BRIDGE RECTIFIER!!!

  6. Avataaar/Circle Created with python_avatars Keith Sherry says:

    Brilliant finish. Can't be unseen. Best visualisation of a motor yet! ๐Ÿ˜‚๐Ÿ‘๐Ÿ‘๐Ÿ‘๐Ÿ‘

  7. Avataaar/Circle Created with python_avatars Yuppi says:

    That freaking piece of SHEET. Being the guest for EEVblog was great, learned a lot about the world in that short video.

  8. Avataaar/Circle Created with python_avatars John Berkers says:

    So essentially an induction motor is like a 3 cylinder rotary engine, but with electricity/magnetic fields doing the pushing

  9. Avataaar/Circle Created with python_avatars Fun Guy says:

    Thanks so much for all of your entertaining and informative videos. I did not know that Mehdi is responsible for all of the light being shined out through our cells. Very interesting.

  10. Avataaar/Circle Created with python_avatars Vitor de Souza says:

    Is it possible generate a 3 phase wave using just one source supply with one output signal with some components (like some capacitor or IC)? Something that be able to create a delay in an wave signal

  11. Avataaar/Circle Created with python_avatars SAHM says:

    Mehdi, I think in the DC motor, the shape of the magnetic field between those poles does not change, it just oscillates in its amplitude, and that's why your magnetic sheet doesn't show anything.

  12. Avataaar/Circle Created with python_avatars MR. Moh says:

    This is a test to see if a shitstick with a certain inappropriate profile picture comments some random shot. Just you wait

  13. Avataaar/Circle Created with python_avatars Norrotaku says:

    swap the fans for noctua ones
    so you can muffle the scream of the beast

  14. Avataaar/Circle Created with python_avatars Pescado Tejano says:

    Have you seen the effect of holding a magnet to the screen of a TV? Maybe you could use that to show the movement. Some of them are really sensitive to magnets. ๐Ÿคทโ€โ™‚๏ธ idk maybe that will help.

  15. Avataaar/Circle Created with python_avatars NoSuchThing says:

    Sheeet hysteresis is to blame? I bet it is very lazy… How about some lower frequencies? 5Hz?

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