How To Make Invisible Gears With Eddy Currents

[@peglor]

Drag due to eddy currents from a spinning magnet used to be how car speedometers worked - the same spinning drive from the wheel that incremented the odometer was also used to spin a magnet near an aluminum disk attached to the speedometer needle. A spring pulled it back to zero so it couldn't spin, but the faster the magnet turned, the bigger the angle the needle moved. Modern cars are using the feed from the ABS sensors, converting it to distance for the odometer and to speed to tell a stepper motor how far to move the needle (Or where to draw the needle if a LCD display is used).

[@BalaMurugan-hk2gd]

Dude just induction motor is example

[@CanadaBud23]

I messed with a few of them and can say they are kind of neat to play with. Little hard to tune though but repining the needle while moving at a certain speed was usually good enough lol. Tend to stick and bounce when it's really cold though so I used to bang the dash till it moved again. I guess leaving it alone until the disc heated up could thaw it and move again.

[@flightmaster178]

I have always wondered a little how the old ones worked. Thank you!

[@louf7178]

Thx. If I'm picturing the same type (would have been GM), I recall thinking... I don't know how this works. Fluid-like coupling but no fluid; no friction. Hmm, put it back together.

[@tomg0]

old electricity meters also use eddy currents

[@verb5006]

Now I know why induction cooktops don't get hot to touch but can boil water

[@papercrowe8772]

Yo thanks so much for this! I’ve been trying to design a battle bot with a loosely connected weapon drive so that the motor doesn’t break during hits, and I think something like this but with both sides being magnet gears might be perfect

[@ninjahunterx7497]

Damn, that would be cool.

[@peglor]

A ball detent style breakaway mechanism would be much lighter and give you the same effect of limiting torque and shock transmission. You could also just use magnets of opposite poles in the two spinning parts to connect them so they spin together with far fewer magnets, less weight and no slip between the two parts until one is stalled. The benefit of using eddy currents would be that you could use a stationary set of coils being powered in the correct sequence to make an aluminum part spin, like in an AC induction motor and reduce the number of moving parts you have.

[@crackedemerald4930]

Now every battlebot sticks to you Maybe that's a good idea for a weapon, a magnet grapple

[@theirishaxe9405]

That would be super weak wouldn't it?

[@thecommenter578]

@@theirishaxe9405 I think so, if the weapon has a lot of mass it would give a hard hit, but since it's spinning just by magnets it would take a lot longer to catch speed again after every hit

[@XJWill1]

You should compare how much the spinning magnets heat up aluminum compared to steel. There is a reason the inductive cooktops specify that cookware should be magnetic.

[@westonding8953]

Good question. I know that copper responds better than aluminum. Steel would be attracted to the magnets so I don't know if that will work.

[@MascottDeepfriar]

I'm pretty sure that most induction cook tops use a sensor to switch off if there is nothing there. That sensor may be based on doing a magnetic check meaning that even though the material is conductive and technically could work it is invisible to the cooktop. This is also a way to protect things like phones and other electronics from the cooktop literally frying them.

[@XJWill1]

@@MascottDeepfriar No, that is not how induction cooktops work. They do not shut off "if there is nothing there". And iron or magnetic steel cookware heats up more than other metal cookware.

[@MascottDeepfriar]

@@XJWill1 both my cheap and expensive induction cook tops turn off if there is not a viable piece of cookware on it. So I'm not sure what you mean by that.

[@XJWill1]

@@MascottDeepfriar Some induction cooktops may have an additional circuit that checks for how much power is being consumed by the induction coupling and turns off if it is too low, but that is not a primary or necessary functionality for an induction cooktop. More to the point, your claim is simply false that the reason magnetic cookware is specified for induction cooktops is to enable a circuit that cuts power if there is no magnetic cookware on the cooktop.

[@ReneKnuvers74rk]

Nice video. Eddy currents are used in high speed trains as brakes. An alternating electromagnetic field induces an eddy current in the track which contactlessly pulls on the train, effectively applying a contactless brake force. Much like the oposite of the force that spins your disk Eddy current brakes are efficient for high speed braking because the track and not a piece on the train is warming up. At high velocities the energy to dissipate is high too (v-squared). At lower speeds the brake force is however not so high. Just like in your setup the torque is at its largest when the magnets were moving and the disk was not. When the ‘gears’ have an equal speed, torque is at its minimum. So when both the track and the train are at a stand still, the EC-brake provide no torque.

[@3nertia]

That is fucking cool! Thanks so much for sharing!

[@3nertia]

So how much torque could these sorts of "invisible gears" produce?

[@ReneKnuvers74rk]

@@3nertia lorentz’s laws will tell you

[@Eduardo_Espinoza]

Good point

[@NC_Isro_64]

Yes

[@FASTFASTmusic]

Every time you release a new video I learn something new. Such smart demonstrations. Thank you

[@flightmaster178]

Always learning something new from you. Pretty cool stuff! Eddy currents are also what allows metal detectors to work. Transmitting coil creates Eddy currents in metal which in turn give off their own magnetic field and thus a sensing coil picks up that magnetic field. Depending on how close that return signal matches the transmitted signal determines how conductive it is and shows a higher number on the target ID or higher on the discrimination level.

[@bsebire]

Wow, love this channel. You never seem to run out of amazing new things to show. Keep it up!

[@wavefuse]

great demo! I’ve always been interested in eddy currents induced by magnets. Another neat thing is to see how a neodymium magnet like the ones you are using will slide slowly down a nearly vertical piece of aluminum and not fall off,, but I’m not telling you anything new here! its just cool. Love your channel !

[@dannyhodson2525]

We just finished the magnetism topic for my gcse and was ashamed when eddy currents were only mentioned briefly not covered because they are very interesting and I wanted to learn more about them and their uses so thank you for covering them

[@jamiepritchard8179]

You'll be sad to hear that they barely get mentioned at alevel 😞

[@dannyhodson2525]

@@jamiepritchard8179 :(

[@55Ramius]

I remember back in 69, I took apart a speedometer from a 1961 -" Ninety Eight" Oldsmobile and saw an aluminum cup-shaped metal on one end and a magnet attached to the cable that ran from the transmission. I knew very little then about magnetic uses in things but once I saw this combination, it hit me how it worked.

[@netts2315]

Indeed. I took out a speedometer from a 96 mazda and only years later actually discovered how it worked. Neat stuff.

[@sereth7582]

This was actually the subject of my capstone design project. We used eddy current disk braking to construct a dynometer for small electric motors. The math behind those eddy currents and how they relate to torque is oh so fun.

[@Salted_Pizza]

"Look how the water instantly boils on the coin!" *proceeds to pick up coin with bare hands*

[@desmond-hawkins]

Cool demo! I'm a bit surprised that James didn't try this in a vacuum, since there will inevitably be comments asking how much of the energy being transferred to one gear to the next comes from the air current created by each spinning disk. Air currents are clearly not the main reason for this effect given how fast the wheels turning, but I could also see how they would add a measurable amount of force that gets passed to each disk from the previous one.

[@droam129]

Hm, interesting thought. You could be right, but when I imagine two metal disks spinning one above the other like in his setup (but not magnetic) my gut instinct is that the spinning one wouldn’t impart any meaningful amount of spinning force on the other due to air current. I could be wrong though. So it would definitely be interesting to see!

[@desmond-hawkins]

@@droam129 Yes I agree that given the shape of the discs he was using (relatively flat and not really "catching" the air around them) it's unlikely they would transfer much energy between them, certainly not as much as what was demonstrated here. But if their surface was more rough or even had raised tabs and they were mounted on their axes in a way that limits friction as much as possible, you could definitely make them spin without touching with just air flow. Really anything other than a perfectly flat disc spinning completely horizontally _will_ impart some force. Just not much.

[@rakshithg9669]

hey everyone today im going to be showing what would happen when you put the invisible gear machine in vacuum (intro to his next vid)

[@desmond-hawkins]

@@rakshithg9669 It's impossible to read this and not hear his voice.

[@thesnoopypanda]

They burn up faster. The air passing over the inducted disk actually helps keep the metal cool and stable. If you put it into a vacuum, there is no heatsink effect and thus the inducted disk will eventually overheat and fail. This is a common problem for eddy current clutches that get insufficient airflow or in vacuum-state applications when their duty cycle is too high.

[@Use2FACTAUTH]

I’ve always had no clue as to how induction stove tops work, this video explained it perfectly. Very interesting, keep up the good work!

[@Abish_]

I love eddy currents. We, in sec. school, made an Eddy current waste separator. We were able to separate alumunium, brass like metals from waste misture. When waste materials were convayerd over the spinning neodymium magnets, chunks of non ferrous metals would jump out off the waste material and get collected in a separate bin.

[@Stark88813]

Amazing Gears... Absolutely Brilliant

[@AngeloGiles]

Very cool video, I always found magnets interesting.

[@jucanavazreque3429]

Actually, that same principle is the one asynchronous motors use: they have a non-magnet rotor spinning to avoid overcurrents during startup or load changes (as opposed to synchronous motors with a magnetic core). When three-phase current runs along the coils of the stator, it creates the variable magnetic field you make with the spinning magnets. This has the disadvantage of having a variable speed depending on the tork they have to overcome, but nowadays are more used than synchronous for big force requirements afaik.

[@Thestorminator89]

I know this is how some water pumps work. Instead of having a shaft through housing and having to use special gaskets to keep water out, just use the magnetic field through the housing. To ensure a water tight component.

[@peglor]

The most common version of this is the magnetic stirrers you see in every chemistry lab, that are driven by electromagnets integrated with the hot plate the beaker sits on. I used magnetically coupled gear pumps from Tuthill Pumps back in the day for one system I designed and built.

[@eddy2758]

Wow using my currents I see

[@ninjahunterx7497]

Dude, why are you so powerful?

[@ashercorbett8089]

This exchange was hilarious

[@MitzvosGolem1]

This is done with pumps and compressors where no shaft seal is allowed.

[@abdullahjaufer2938]

You're awesome brother! Millions of subscribers, yet underrated... Awesome vids🙌

[@DigitalicaEG]

This channel is so underrated, love your content!

[@joshuvastephen1377]

After so long I really understood what Eddy current is, I vaguely got it when I read about it multiple times but now after visualising it in a experimental form I could understand it.

[@terrafirma9328]

Have you tried making a demo of invisible bearings yet? Instead of ball bearings, magnets are used to eliminate friction.

[@gbcremont]

Вы умеете удивлять! Класс.

[@wheelbite9]

You made basic versions of so many car parts in this video, from an alternator to a (really basic) automatic transmission. Love to see it. :)

[@atom2319]

Best demonstration of Eddy currents yet.. so thanks..

[@macaaris1018]

That heating part was very nice 🔥

[@adamreynolds3863]

I think it would be cool if you did another video just like this, but include a copper disc or another type of non magnetic metal disc to compare them!

[@fendysusanto876]

Did you really watch the video?

[@ronmayer8685]

@@fendysusanto876 :D

[@ManyHeavens42]

Your a genius, thanks🎉 Your Really coming together

[@BaristaPablo]

You should try an actual gear inverter using magnets. You place a sandwich of these alternating magnets on a ring pattern with another ring with ferromagnetic materials in place of the magnets in the middle. When you turn one of the magnet rings the other ring will turn on the opposite direction without touching. Gear reduction also works by using different number of magnets.

[@mrutyunjayasahoo971]

Thank you sir for giving us such demonstrations.

[@drakonyanazkar]

This has got to be one of the most interesting videos in the channel for me so far. Just the very sight of aluminum interacting with the magnetic field blew my mind away!

[@elgalactico3645]

Thanks a lot man I had no idea induction cooker was made using this principle , in fact I didn’t know that eddy current could heat up a conductive metal resting above ! Wow

[@elgalactico3645]

I know that eddy current is used in the train brakes but wow

[@dancoroian1]

I think it'd be really cool if you made the receiver "gear" disk as thin (i.e. as light) as possible, and maybe beefed up the propeller a bit in terms of thrust (and not weight ideally). Then, with a bit of luck and some precision placement, ideally you could get it to levitate above the spinning coil -- it would spin up so fast that it would start rising and getting further from the coil, inducing a feedback loop wherein being closer causes to spin faster and move further, which then causes it to spin slower and move closer, etc. until it (hopefully!) finds a nice stable equilibrium

[@drako7222]

The only issue I could see with this is it flying off to one side or the other you'd have to have some sort of string guide or something to keep it above the magnets

[@dancoroian1]

@@drako7222 yeah maybe you could make the body of the propeller hollow (if it wasn't already) then drill a hole in the middle of the bottom disk and thread the whole thing onto a thin metal mast anchored to the table

[@BalaMurugan-hk2gd]

If you make the material thin then there will be decrement of edye current. So less levitation

[@dancoroian1]

@@BalaMurugan-hk2gd I see... you don't think there's a middle ground between thickness/weight and strength of the eddy current that would make it work? Is there a lighter metal than aluminum that would be stable enough and otherwise appropriate to use? Maybe lithium (disclaimer: I don't know what I'm talking about)

[@superbasyboy]

@@dancoroian1 It's about the ammount of electrons in the material. The electrons start moving and this creates a force. A thinner material has less electrons, thus less force. If you want to use a lighter material that creates the same force you will need a high electron material. But high electron amount is connected to weight indirectly if I'm not mistaken. So ideally you want something with as little neutrons as possible while being heigh in protons and thus high in electrons.

[@ian6083]

Amazing demonstration, once again! This one is of particular interest to me. Keep up the great work!

[@amfkj2]

My son and I love watching your videos. They are entertaining and educational! We hope you continue to make any more.

[@eklhaft4531]

2:23 Electroboom moment.

[@akuljamwal3085]

Except, he'd say f*** s***, then cut to himself talking.

[@powderslinger5968]

I have seen slip clutches on big industrial drives that had magnets on both wheels but not something that was "geared" like this. Cool idea. Using eddy currents you can have a loosely coupled and geared slip drive (consumer air fan) and with magnets on both wheels you can do the same with nearly no slip (Industrial or automotive transmission?). Particularly useful since the slip can be modulated like an automotive clutch.

[@Lampe2020]

2:22 I thought only ElectroBOOM would do so but you grabbed the coin that flash-boils water with your bare hands! I was laughing so hard!

[@cortneyholt]

Love this bro, counter rotating field generator two plates of fr5 with directionally patterned 2”copper strap 6’ and 8’ natural green g10 discs with the copper strap in an accelerating electrode pattern. The lower disc is sucking up air, the upper 8’ disk is shooting it out. Mount this in an aluminum skirt with mesh under the aluminum charged negative as a target for the radiation to flow through and run down the skirt or hull of the craft, now mount yourself a chair and fly!!! In your homopolar aerodyne compliments of electro gravitational potentials P2

[@David_Mash]

Works a lot better with magnets in the reciever gear, gear reduction and direction is based on ratio.

[@dancoulson6579]

I wonder if this could be used to make a torque converter for an automatic transmission. It might be a fluidless design.

[@NoName-fn6ee]

This was one of the coolest Things you ever showed! Anything about Magnets actually!

[@RickLambert963]

Watch me boil water on this quarter; then he grabs it with bare fingers. That was an Electro Boom moment. 😂🤣

[@JayNKnight]

Ok, this is one of the coolest experiments to date!

[@atikattar1104]

I Have A Question. In Order To Create The Invisible Gear Like This, Do We Need A Conductive Metal (Like The Aluminium Flywheel Shown In The Video) Or It Will Work With Any Metal? And Also Please Make More Videos Of Magnetic Experiments.

[@michaelholmes2101]

Super cool. You are so skilled and knowledgable

[@mattp422]

Another great video. It would be interesting to quantitate torque vs distance or composition of flywheel or field strength or angular velocity of the rotating magnets (so many variables to play with!

[@ericbarnes3829]

As an Engineer I can tell you that invisible gears are difficult to make. Gears are made with Gear Hobs, and depending on the Pressure Angle and Pitch each Hob is made special and precise. The problem comes in when cutting the invisible gear material, zeroing an invisible Gear Hob is difficult at best. And advancing the Invisible Dividing head the proper amount is extremely hard when you cannot see the tool, the Divider, or the gear material. That is why they cost so much. But they do run quietly with very little gear backlash.

[@pranavsreedhar1402]

Thank you for this insipirational video!

[@TheSkepticSkwerl]

I wonder how this would work as a torque converter in a transmission instead of a liquid based one. 🤔

[@mouryayanamadala923]

I never taught eddy currents to be interesting in my class 12! But this video did something!!😶‍🌫️

[@falin9557]

two facts about what you said: 1) Cody's lab made a video melting a bullet with magnets 2) I have a pan that is barely balanced on it's edge, so when it's putted on an induction cooker, it will tilt, the cooker will turn off (because it doesn't detect it) so the pan falls down and repeat

[@A_Jung]

It wouldn't be an Action Lab video without an ”Ouch!".

[@bstok-tmtm876]

this is my favorite video so far

[@ThePrufessa]

This man is always blowing my mind

[@obsidian9998]

1:54 Mechanical electric stove.

[@pappumanishsharma]

This guys nailed it

[@konoveldorada5990]

Kid: *I want a Beyblade.* Mom: *We already have a beyblade.* The Beyblade: 2:19

[@yabbaso]

Just reminded me of the magnetic clutch used in the old Big Trak gear-box to make both DC motors spin at the same rate.

[@doiron12]

It would be interesting to see the heat formed from the eddy currents with a thermal camera!

[@SaiyedR]

I love this kind of invention 😮

[@cathysupp9493]

The BEST sound ever; Teacher’s surprise when that quarter spins Wow that’s cool! *is this sort of how induction cooktops work? There’s got to be something else going on, or pots would be flying off the surface

[@babayada2015]

Hey @Action Lab. The spam comments are getting too high in numbers. Please block the links from chat and add some moderators to delete those nasty comments.

[@ninjahunterx7497]

Yeah, seriously. Those are everywhere.

[@insanecamo]

It'd be cool to see these stacked

[@jeffreyrood8755]

This is the kind of thing I'm interested in so I love it! Thank you for this one 👍

[@colemiller2149]

This man really grabbed a coin that he boiled water off of while it was still heated. Bravo and props for leaving it in

[@zukaro]

It's cool stuff, and honestly it'd be nice to build a vehicle which used magnets to keep parts from touching, to prevent wear. I imagine it would be possible, not sure how difficult or expensive it'd be.

[@viatueur73]

I really like your videos! They are very entertaining and educative

[@randyscorner9434]

A company called Magnadrive tried to commercialize this for actual gearing on motors. Shafts did not require perfect alignment, bearings didn't wear out, and it was quieter and more controllable for speed. Unfortunately, they could not manufacture them in volume for these specialized needs.

[@louf7178]

Great video. I thought pans for induction stoves could not be all aluminum.

[@Term-0]

it depends on the type of inductive stovetops. different inductive stovetops might use different frequencies, and different metals are more susceptible to eddy currents at different frequencies (this is a bit of a simplification).

[@BenjaminMarshallScienceMan]

You can also use a similar setup to make gears of a specific ratio. I made a video about this if you're interested.

[@sanjeen2503]

In an automobile internship contest, I had presented a similar idea of having synchromesh replaced with neodymium magnets and aluminium gears inside a transmission. One of the panelists was like "eddy currents? We don't want sparks and fire inside a transmission!" Lol.

[@daviddavids2884]

well. it was a Dumb idea, regardless because, if a significant load is present at the driven wheel before it is turning, the results would be No motion, and a Hot driven wheel.

[@sanjeen2503]

@@daviddavids2884 What's the alternate in that scenario? I guess ground shavings of dog teeth going into the lube oil? Or a heated up synchro? Did you forget that clutch exists? EDIT: perhaps you thought that the magnetism is the only thing transmitting the load. But I proposed alternative for the friction based synchronizer only, not the dog gear teeth which actually transmits the load. Nevertheless, it was a bad idea, because friction synchros can bring relative speed to 0, but two parts using eddy currents to synchronize will have always have relative motion, just like an induction motor (and as opposed to a synchronous motor).

[@cardinalhamneggs5253]

This is how the Hacksmith Industries Hoverboard works.

[@lumsdot]

I think control rods in nuclear reactors are spun and screwed in and out using an external spinning magnet, that way it can be sealed and is safer

[@andrejar6166]

And that's how we can make hot coffee with a coin. Great content here!

[@kamil4151]

Interesting was that it was turning the same way as the magnet wheel, regardless the position of the two wheels. I was expecting that it would act like like a gear and if it was just the edges "touching", it would turn the other way. Interesting.

[@u1zha]

It does act like a gear. 3:27 the flywheel turns like a gear, opposite way to the magnet base

[@lexiecrewther7038]

I'd like to see whether this actually gears up, ie higher torque at lower rpm, and whether it is more efficient than a transmission. I can see this benefitting a boat propellor

[@Anxhs]

time in this channel passes faster than in real-world your channel itself is an example of a frame of respect.

[@SouravBagchigoogleplus]

Eddy current clutch used in diesel locomotives to rotate the radiator fans.

[@tillson8686]

"Look at how the coin is so hot that it can cook water!" **Picks it up** 👁👄👁

[@flaplaya]

Really neat phenomenon awesome videos. The aluminum flywheel? Just a touch off center :) tip: never un-chuck work from lathe until done.

[@hamedelahi2249]

Excellent! You can make a charger or wifi electricity with it.

[@michaelzumpano7318]

You constantly surprise me with your topics. The way you demonstrate and describe the physics is so familiar, so easy to understand. I want my grandkids to learn physics from you… when I have grandkids.

[@symbudhanyasi431]

Sir can you please start a channel to discuss the basics and complex phenomenos of physics..for understanding ❤️❤️..love your videos bro

[@Entity_BlackRed777]

Very recent, nice experiment!!

[@mrxmry3264]

3:22 thats basically how an induction motor works.

[@evnsriram]

You have better knowledge than many professors around the world! I love your ideas!

[@wheelman_33_]

Wow I was just talking about trying this. Thanks for this. My idea was a little more complicated.

[@Mr.Useless420]

This could be great for other applications

[@marsmountain2794]

Water, fire, air and dirt

[@akuljamwal3085]

One element to rule them all- CABBAGES!

[@greatPretender79]

This video is way too short! I love magnets and could stare at them forever. And I learned how those magic stoves work

[@realracerz3242]

Just curious, where do you get ideas to try these cool experiments.

[@10111stef]

A clutch that will never get burned

[@kvn12pal]

I love your demo. They awesome. You make science cool.

[@chaseallen9390]

Where can I get the materials to build this? If you gave me a list, I would greatly appreciate it sir! Thank you for the video!

[@jctoad]

This idea has been used for over 50 years for aquarium filter pumps