One main reason I keep enjoying your projects is that you do a great job explaining step by step process involved even in the most basic things. Great job sir.
Hi thanks for a very informative video. I do however do not agree with your indication of the magnetic path. The magnetic fields will split at the centre pole and flow the the other two faces generated by the cut you made. If you lay the magnet on its side on a piece of paper and energise it lightly and then sprinkle iron filings on the paper the filings will align with the field and you will be able to see where the magnetic path is.But none the less I think it was a cool video and was presented in a very logical manner. Thanks very much Louis
Not sure if someone has already pointed out this minor detail, but I will go ahead and do so: when he drew the magnetic field lines for the transformer after being cut in half, the field lines should have actually gone from the middle section out towards the two open ends of the transformer at the bottom, not towards the closed end of the transformer on top. The vast majority of the flux goes in and out of the open ends, not the sides or top. You will notice this if you try to stick some iron on the top of the transformer- it will not stick nearly as well as on the open ends at the bottom. Very cool video though, and nice way of illustrating things!
Energy flows in the path of least resistance. Therefore the flux will take the straightest path from the copper the iron core because the air presents higher resistance to the flow or current produced by the power supply. Energies natural state is to 0.
@@buckaroundandfindout Yes, the magnetic field will avoid going through the air any time it can, but if you put a gap in the path of the magnetic flux like in this case here, it will go through the air. The two ends have one pole, and the center has the other. The magnetic field is trying to complete the circuit between those two poles in the most efficient way possible, therefore it will come off the ends like I described. Any other path would be longer than that.
@@HeyChickens constructive Central pedal divergence is what you are referring to. Yes some flux lines will flow through the air because there's no room for them in the path of least resistance. Especially in the case of an electromagnet where the force is being pushed into the dielectric field thereby forcing the internal forces to become external. Gaussian flux is introduced to a piece of steel in which it is changed fundamentally on the molecular scale therefore allowing a bypass of the flux fields in what is known as counter space. Where you see the flux in a feral cell is usually the path of least resistance ergo where the force is not located in the flux line. The force is in the space in between the flex lines, that is where you will locate the bulk of the energy that is being displaced via the lack of pathway in least resistance.
Furthermore magnetic attraction is a little bit of a misnomer as far as the words and language describe the actions. It would be more accurate to say that two pieces of metal rushed to a null point that is a convergence of flux lines in relation to the spin of electrons due to the polarization of rare earth metals. Ergo Force equal to attraction is acceleration to a null point.
We just had roofers replace the shingles on our roof and I was thinking of how I could pick up all the nails that where left behind. Something like this with a lite weight battery on wheels to go over the ground and rip all the nails and metal from the soil would be perfect.
Very impressed👍When testing heavy loads, make sure to insert safety link in both directions (use slightly loose rope), if the magnet fail at 300kg or more, the steel block will hit the car and the magnet can hit you with a great force, be careful!
Yes! Newton's first law of motion comes to mind, "Every action has an equal and opposite reaction". Yo certainly don't want that magnet flying off and hitting your shin, that would break both tib and fib easily
Put different sized nails into different types of soft and hard woods at different depths and see if you can devise a practical electromagnetic nail puller.
Nails have so little surface area for the magnet to lock onto, it would be virtually impossible to devise an electromagnetic field (out of a microwave transformer anyways) capable of pulling a nail out of wood, especially hard wood...
Great and useful project. I'm a woodworker with a good quality cabinet saw. I use two electro magnets in a wooden feather board to guide my work through the saw instead of using my hand (for obvious reasons), I can position the feather board anywhere on the cast iron table to fit the work I am cutting. I wished I had seen your vid before I purchased the magnets from Aliexpress. Going to build your drill press vice next.
Very informative video and it gave me great info on which type of voltage/current to use. Here's a project that I'm starting to work on. I go prospecting for gold out here in Arizona and we have a lot of " black sand " in our good paydirt. I'm taking a 4" pvc pipe and going to tape/strap 2 of these on either side to pour the dirt through so the magnetic field will "stick" the magnatite ( black sand ) to the sides and let to paydirt fall through for further processing. Challenge is to build one of these and post a video. Thanks again and I'll post pics when I'm done.
The field lines will still VERY MUCH prefer to be inside the iron so the south pole should be extended to all of the remaining iron. The field lines in air will simply jump the gaps from the central exposed iron to the two ends. From there they will be inside the iron for the rest of the loop. Also, in truth, the poles are only at the end surface; inside the iron the magnetic domains realign to cancel the field almost completely.
So what if you replace the secondary coil with another primary coil in an MOT? You would eliminate having to chop off half of the block, but would it double the power? And would you connect the two coils in series or parallel? And would you reverse polarity on one of the coils? Would it matter in AC, DC? Sorry about all the questions. 😂
Well I know you can't reverse polarity on one of the the coils, you def want the same, but that a good Idea if you have 2 of the same broken microwaves. Lol. Not sure if parallel or series would create a stronger magnetic pull. Im thhinkin series cause more amps
I had the same question couple weeks ago... after cutting a mot into the E shape I placed another coil on top of the primary coil.. connected 2nd coil to the leads of primary flipped the switch and POW!! i thought fk it blew up .. then simultaneously heard a loud thud and something hit the top of my right shoulder... the 2nd coil I placed on the primary coil shot straight up off the mot transformer.. broke the wires off itself as it headed for the ceiling.... I was dumbfounded to say the least ..
@@codyramos3200 I knew there would be polarity issues, but didnt think about the power involved if connected north to north. Yeah, i guess it would do something like that. Did you try reversing the wires?
@@siggyretburns7523 uh I can't say if I did ... I soldered 1 end of the 2nd coil to another coil to make 1 large coil to work as a secondary coil for a step up transformer... it takes a ridiculous amount of wire to go from 110v to 550v ..
I’ve seen loads of videos on microwave transformers converted to spot welding transformers, but this is the first time I’ve seen a conversion into an electromagnet. Nice work! 👍 I’ll give it a try myself.
Yup, a storm's power surge took out my microzappr, I knew there was a good size transformer in it and cut two groves with an angle grinder. Having an old truck battery with external cell connectors, I can use at 6 or 8 volts and not overheat the primary coil.
@@headbanger1428 a microzapper is just another term I use for a microwave oven, that's all, Maybe I should have called it a micro-doo-hickey, a micro thing-a-ma-jig.
Keep reducing the power supply to the magnet ( volts and amps equally ) to see at what point it fails at 300 kg's, then find your wattage from that and divide it by 300 kg's to see your watt strength in Kk's lifting power. Great video, well made and informative, would never have guessed that a low resistance in the system would make such a difference.
That's a surprising amount of holding strength for such a small magnet. Maybe it could be used with cart type frame for a rolling gantry to move things around.
E-magnets are better for reaping/tearing uses than for lateral/sheering. Just think of those permanent magnet pickup clamps; when you turn them off you basically rotating the load to short the poles...
What was the temperature of the winding after a few minutes? I would like to know the result of reducing the current to see when the 300kg is released.
Yup. Third that. What was temp° and could you please do a reduction in current + a fixed weight # so a ballpark value can be determined! :) thanks lots. Great channel and good on you!
Very usefull video. Thank you. Please try to compile a temperature curve e.g. for 30 minutes of metal machining. Somebody in other video checked the different voltage for input - 3V, 5V, 15V etc. Suppose max weight of metal machined piece cca 10kgs. What a appropriate Voltage by relevant temperture? What about a dBA or vibrations during work?
Wow, very impressive cuzzy bro! Just one bit of feedback and maybe someone else has already pointed this out, don't have enough time to read through all the comments. That is in your explanation of the magnetic field path in the cut core, you've got it going from the center limb to the back of the core when in reality it is the same path as in the uncut transformer, via the left and right limbs of the core. You can confirm this by checking the magnetic strength at the back of the core and you will see that it is just as weak or very close to that around the uncut core. 300kg plus, holly sh....t! Keep 'em coming, great video and very enlightening. Cheers and stay well from across the pond.
I've watched two videos on magnetic vices. One created a "magnetic table" that holds the work with the vice mechanically attached to the table. The other used the magnet to hold a traditional type vice to the table. Both have advantages. If you want to get really creative you could try removing the other side of the core as well and see if the drill press table would work as one side of the core making a magnetically held magnetic table. 😎
Good to see that I am not the only one obsessed with magnets! I couldn't help myself - I made a video on my channel several years ago. You have given me a few more ideas...... I have several microwave transformers that might be taking on a little transformation themselves 😁 Next term I will be teaching night classes on automotive electrical subjects. I drag around a rolling trolley with heaps of wire and you guessed it.....lots of permanent magnets as well as electromagnets to show students how solenoids, motors, relays and other tricky electrical components work. I usually use a rotor out of an alternator as an electromagnet to show magnetic strength holding a solid shaft of steel, but your idea might be a good alternative (excuse the pun) option! Keep up the good work! 👍 G'day from 'Across The Ditch' MiracleMAX
A very good combination of theory and application, well done! One thing though: with a cut up transformer, the vast majority of the magnetic field lines go from the center bar to the side poles, not around the transformer (9:32). That's what causes the field loops to be closed when an metal object goes across.
If cutting 2 slots and leaving it full size better than cutting it down as all clips shown? More iron larger surface area? Slots cut also would be nice flat and more iron to stick to.
You could make an electromagnetic door lock. Also, the reason I am studying magnetics is to make a large magnetic lift for scrap metal. I think you very much for the ideas I have taken from your videos. Great job.
The commercial magnetic bending brakes are using 220 volt electro magnets generating 6 tons force spread out over 48 inches to secure material. Would like to see what you could come up with!
wow, i had not expected that strength with only a bench power supply. I was thinking about making a big electromagnet from scratch but when you can just grind away the weld on an MOT to have a super good one at hand, that'll serve me a lot of work.
Bit of a worry using KNOTTED straps = points just waiting to break suddenly! I would have used some 10mm polyprop rope, but that's me. Q: What might be the difference in magnetic force under identical circs, but WITHOUT removing the excess laminations? Also, I'd have been interested to know how warm those windings got after a few minutes of 12V@8A.
Love your videos. Today I started a project to build a tape demagnetiser for old Video8 tapes, audio cassettes and reel to reel tapes. I found a good looking design and tutorial online that repurposed a Microwave transformer. I found a 240 volt LG Microwave oven with a primary winding rated at about 9 amps and pulled out the transformer and micro-switches. After removing the secondary winding as you have done I was left with the primary winding intact which I tapped up to be flush with the top of the core face like your electromagnet. My question is, I cannot get any DC resistance reading on the coil, not even .01 ohms. I cannot see any damage to the coil causing a short. I wired the coil in series with a 40watt incandescent globe which turned on normally, (not a good sign I think) I'm nervous about putting 240V across the coil in case it is indeed shorted. I suppose I could put a variac in front of the coil as well as an isolating transformer (I have a 1KVA ISO transformer) to help upsetting other electronic equipment if it violently trips my RCD. My other option is to wind a new coil. What do you think?
Interesting. A New Zealander from the Southern Hemisphere places South above North on the magnet illustration. I wonder if that is typical? I've always seen North above South but I'm from the US in the Northern Hemisphere.
Awesome video I enjoyed it… hopefully everything is cool down there in New Zealand looks like you guys are on lockdown over one single case! No deaths! Better days ahead ❤️
Something of note that could be relevant. Magnetic field is proportional to amperage times number of turns (plus or minus difference of losses) A 200 turns at 4A electromagnet will have almost the same strength as a 400 turns 2A one. Only case by case differences will make one or the other slightly stronger. Well, there are other factors to take in consideration when choosing one over the other, such as power loss into heat, thermal properties,... but that is more relevant when winding an electromagnet from scratch. The point here is to use easily available material and minimum complexity of modification. Which microwave transformers fit perfectly, plentiful, cheap and easy to power.
If you don't mind a question: how can i determine the max or correct amperage to run thorough a primary winding? Can i use the labeled values on the transformer? I also have a question about height of the legs on the "E" frame the windings are in. Is there a sweet spot in relation to the ark of the magnetic field for an increased gauss value or just closer is better? Lastly since the magnetic field is the same at each pole can I use plates on the side and leave both poles ooen to have the ability to hold items on top as well as hold the device down to a metal surface as needed for a drill press? Thanks in advance for any illumination you might care to offer.
Great video man! You clearly put a lot of effort in it, and it shows. It would be a great electronic lock for your workshop. Not at max current, that would be too harsh for the winding. Or if you make it waterproof, it could be a great magnet-fishing device. Power it up with a car battery. And I sure can use a scaled-down version to get the thousands of tiny screws and bolts out of my long fibre carpet.
Great video, excellent descriptions! I'm wanting to build a trommel with an electromagnet Incorporated at some point to remove nails from wood ash. Thank you for posting!!!
@@Graeme_Lastname I like good answers !!!! Thanks for explaining me, however ....could you please say more about 'basic principles'? Thanks a lot in advance.
@@isabellemarquez4806 Basic principles give you, among other things, the direction of the magnetic field when the direction of electron flow is known. Way to much info for a comment post. B well m8. :)
In other words a transformer core contains all the field, as long as the core isn't saturated. Thus external iron doesnt interact with the magnetic fields inside the core. But where the field exits the transformer core, they can interact with external ferus metal.
The field lines are are in a close circuit. The horse shoe magnets would be having pole pieces when stored for long time. The torroid core design assures self shielding meaning any other torroid core transformer can be placed just beyond half the diameter distance of the bigger one. In the case of a solenoid winding to minimize/ avoid interaction the coils would be placed perpendicular to each other and in the case of a third coil, it would be placed in the vertical plane. You can observe this in the radio circuits.
@@subramanianr7206 if one rewatches the video 5:14 , the original core before being modified was expelling some magnetic fields. That's indicates over saturation that inturn indicats one should run fewer amps due to the fact that the rate of increase in the magnetic field drops due to drop in a decrease in permibility. en.m.wikipedia.org/wiki/File:Permeability_of_ferromagnet_by_Zureks.svg But, on rexamination of transformer design, i might be wrong on the saturation current after the core was modified. Transformer design sometimes introduce an air gap to increase the saturation current level. Cuting the core in half introduces a large air gap in the magnetic circuit. Presumptively, that will also increase the saturation current level, maybe well beyond 4 amps. The large air gap now allows for using the core as an electronagnet. But when a piece of metal closes the air gap, the saturating current level will drop. Take away is that there are more things to consider what current one wants to run depending on the core and how one will use it.
The magnetic field is proportional to the number of turns times the current. Since you are using DC, the larger number of turns in the fine wire coils would have needed less stress on your power supply.
Yes but it is also proportional to the current IIRC. So if he was able to increase current more than he was able to increase turns, this was the way to go. His risk on going to small turns was that he would have to lower current to avoid overheating
Excellent demonstration of exactly the kind of info on electro-magnets that I was looking for. Thank You! I will be watching if you decide to utilize AC power in demo and it will be interesting to see the pro's and con's of DC vs AC with powerful electro=magnets.
You can limit the current, from an AC source, by using use an AC capacitor, on the hot AC lead of primary, and using the Capacitor Reactance Formula to calculate in Ohms.
@@OtherDalfite Wasn't what I was saying. I assumed you would use a rectifier, but, before it gets to the rectifier, you can limit the current using a capacitor on the hot AC lead using capacitor reactance formula. Example: 108 UF capacitor limits the current due to Capacitor Reactance Capacitor Reactance = 1 / (2 * PI * Frequency * UF / 1000000) EX: 1 / (2 * 3.14 * 60 * 108/1000000) = 24.57 Ohms 120 VAC / 24.57 OHMS = 4.88 Amps
Different steels have different magnetic saturation points, where the magnetic forces pulling towards the iron core is drastically reduced per amp going through the windings. If this point was reached at say 80% current draw of what he is drawing in this video, and then half the current to take a measurement. you only had a 20% drop in magnetic force but half the current draw, thus giving a false measurement. (These numbers are straight out of my ass, and only to prove a point)
very cool. so small yet so powerful. I made an electromagnet using a 65-pound steel bar and about two hundred feet of insulated copper wire. then hooked it up to a 12-volt deep cycle battery. it was strong, but not as strong as that little one you made. And it got hot quick. Thanks for the perspective. Ill change my design. ; )
Great video. I am trying to build a seriously powerful electro magnet using the microwave transformer. My question is, rather than cut the excess metal off of the ‘E’ shape, could I install an additional coil winding (1 or 2) from a second and/or third disassembled transformer? Installing 2 or 3 windings on the inner ‘E’ part. Then wire in separate winding in series from the power source with a switch. It is my understanding, the more winds the stronger the magnet. Any comments are appreciated. I plan to try and power this off 2 older diesel truck batteries wired in series for a 24v power supply.
Schematix, I believe that welding the laminations together weakens the overall magnetic field. There's a reason they have them split into several individual pieces.
@@Graeme_Lastname right, to reduce eddy currents flowing around in the core, much like how an induction heater heats up the "core" of whatever iron or metal is inserted inside the coil. So essentially this wouldn't affect a DC magnet situation because the core is never experiencing any eddy currents since the direction of flow isn't changing. So welding the laminations doesn't affect anything. Correct?
So number of turns increases flux too. How about cutting another transformer in half and comparing the flux of the high turn, low amp side against the low turn, high amp side?
Make a portable wheeled card electromagnet for wheeling over the yard to pick up miscellaneous screws and nails. It'd be cool to make one for separating black sand from the other sand.
You can double the range of your measuring instrument by using a simple tool called a 'snatch block' which consists of a single pulley, You will have to move the cable running thru the snatch block twice as far as you would be moving the load, but you would only be using half as much force to move it. Just measure that force and multiply by 2 to double the measurement range of your instrument.
Your video is great, you don’t just explain things really well but you jump in with everyday practical experiments we could all do. That is really powerful and to think it came from an old microwave transformer too, I will use this on my own project, thanks
Excellent. This was fun. Two questions: 1. Why 0.5 to 2.0[ohms]? Is it ONLY about what resistance across the fixed DC source voltage which allows the desired peak current? 2. What type of supply was used in the second (car tow hitch vs. steel pole) test? Was this also an adjustable bench top supply, but with higher current capability? 3. What happens if you hook the coil leads to an AC source, eg. a 120[v] (rms) from the wall plug? OK, that was three questions. Thanks again. Very educational.
Quick question about when you cut away part of the core and it was still an intact transformer. In addition to the field mostly interacting with the core itself, wouldn't you also have some loss due to the other coil? Or would that only effect it if there was a complete circuit with a load on the other coil?
Excellent video particularly on ease of selection of the transformer. A very cheap mag drill is in my mind I always wanted, and, what I really want to do is a cheap method to have a kill switch on my digger I need to be activated by trips for safety where the "real thing" dam near costs more than the machine. (the magnet will hold the fuel shut off open and another can similarly lock my hydraulics simultaneously on the same electric circuit). Thinking that much power would also work as a lock on the slew control (it's the real one that kills people tripping or catching clothing) in a circuit where if it's not locked the fuel and hydraulic one power off). Been trying to find a way to do this for ages.
great explanation. Wish I had you when doing my apprenticeship. Got there in the end haha. Looks like you could have used an electromagnet drill vice at 6:19... What about an electromagnetic drill press bed so you don't have to use a vice at all. Still looking for something similar for aluminium too...still looking
Speaking of saturation. Seeing the core expelling some magnetic field at 4 amps means 4 amps is too much magnetic field for the core and you have saturated it. You should have dialed the voltage down to push less current through until your under saturation point. Then you can cut open the core. Pushing more current passed saturation does little to add to the magnetic field past saturation. Thus the extra current does little more than create heat and unessesarily waste energy. (Added after have posting to include new information and avoid confusion) sometime Transformer designs include an air gap to increase the point where current saturates the core. That said, cutting the core in half introduces a large air gap which could presumptivly push up the point where current saturates the core to well beyond 4 amps, but if one closes the air gap with a ferrous metal, it will lower the saturation current again. Takeaways: There are more things to consider when determining what is the ideal current for a given core and how one intends on using it.
I have an idea/question. What could you pass over the magnet to disrupt the field and how much control could you have over it? My idea is to have something like a strong magnet at the base, with something to disrupt the fields set above it. Above that I want a tray filled with ferrofluid. I want to see how much I can control its dance via altering and possibly reshaping the magnetic field. I have a degree in electronics but my courses merely had the minimal obligatory mentions of magnetics so I'm just playing to see what happens.
I’m looking at building a system for our Jib crane at work to act on a switch to act as a brake system to hold the trolley in place (to a point) and possibly the swing
Thank you for this informative video ! I surly could use the electromagnet that you demonstrated, to pull dents out in autobody applications ! The setup that you have would help me GREATLY in repairing my truck !
That's a really good video, the best one I've found on that matter. Thank you so much. I need to make one or more of these in order to make a magnetic table for cleaning plasma cut parts. I'm a bit worried about it's electrical safety. Is there something I should do in order to avoid someone getting electrocuted in a magnetic table fitted with some of these electromagnets? Is just grouding the table enough?
good boy.....same as i use...angle grinder/chop off saw (homemade from furnace motor, and microswitches from microwave).....to re-create MOTs for chargers, welders, etc. made an 18 volt dc supply for cordless tools, converted to corded tools, ...mots rewound for 19 volts dc with capacitors and bridge rectifier.....all work wonderfull....good for you...
I can't help thinking that by welding the laminates together you reduce the flux density of the core as all the plates are now connected. Perhaps a better way might have been to give the outward faces of the transformer a coat of epoxy? Or even powdercoat it?
I didn't see any comments about the mistake in diagram @9.21 I am confident this is secondary school science stuff....and unless I missed the reference to a basic magnetics concept...i.e. no mention of ampere turns vs flux density ... Schematix is testing you....and you didn't pass!....fun use for a microwave tranny though....and what degradation in lift performance if the legs of the core was left as it was initially cut with angle grinder...as I suspect that not that many have a metal cutting band saw ? Thanks for the great idea and future project !
The diagram at 9.21 is absolutely correct. If you want to find out a mistake it would be that he had not marked the arrows on the lines to represent the direction of the convention; but surely he was drawing it from the N pole to the S pole. In the whole transformer the field lines are closed. When the pole piece is exposed by cutting off it keeps attracting the iron with a heavy force. You should refresh your school physics, I believe.
@@subramanianr7206 The diagram shows lines of flux without any effect of the core. Are you saying that the core has no impact on the concentration of flux? If so then I suggest I am not the one who needs to refresh school physics!
What if you made like 10 of these and attached them to the loader of a tractor? Curious as to how well it could find old nails and screws for construction site clean up.
What is the simplest way to make a small magnetic table so that i can make a small surface grinder about the size of an a4 piece of paper. My financial resources are very limited since i have spent most of 20 years in bed. Most of my metal and wood is what i find near the local garbage dump on each block close to home. I really do not understand electricity though i did completely rewire my house in new york 40 years ago. Thank you for your time and help.
Very nice demonstration but I have a question. If you have 4 components like that, can you link them together like in series? What will be the result, please?
Though difficult to measure the absolute force, I would like to see the performance of two equal EM's, one with a timed momentary current supply mounted stationary above the other mounted atop a piston connected to a crankshaft with a momentary, timed commentator current supply. The crank mounting apparatus (block) and stationary (head) mounts of aluminum so as to not interfere with magnetic fields. Ideally, the timing and supply current electronically controlled with opposing currents supplied at the top dead center (TDC) of piston travel. Once in motion, supply current can easily be generated from the resulting crank rotation or through pick-up coils in the cylinder walls. In theory, the instantaneous opposing magnetic fields of the magnets could produce a force, however marginal, similar to that of internal combustion. Furthermore, this force could be produced on every rotation rather than the 4 to 1 of a gas engine. Obviously some engineering to work out, but feasible, don't you think?
That is very interesting... !!!!!-----> You can get a higher weight reading off your scale there. use a pulley system and then multiply the reading by the ration of the pulley or a falcrum. With the falcrum you it is basically by percentage. if it is in the middle then it is 1to1 if 1 third down then its 1to2. Then use the scale on the 2x side and magnet on the 1x side and if you measure 300 then its actually 600 strong. IF all else fails...How much does the car weigh and are you insured?
You could use your microwave electromagnet for the base magnet in a mercury vortex drive; so, you can vary the field strength and direction giving you additional control over the vortexes rotation.
Awesome advice and well presented! I learned a lot. I do have one piece of advice. Next time don't heat the laminates in the core. They do have lacquer on them for a reason. Laminations perform better in a transformer core than solid iron or molded ferrite powder. It's important for the laminates to be separated from one another with the lacquer. If they touch one another conductively it reduces the efficiency of the core. Next Time start with a new core that will not be damaged by taking it apart or welding all the laminations together into a solid conductive core. In the least don't weld the laminates together. Perhaps put it into a vice while applying some two part resinous bonding glue.
@@richardsellars8598 I used the term lacquer but I dont know what material engineers use to isolate the different laminations. I only know that it's a proven fact that isolated laminations create the least resistant transformation. You'd have to ask an engineer how they manage to retain isolation because i dont know.
I needed a such Electro Magnet for an innovative project and the one you introduced was nice. Does it work with a car Battery? Doesn't it damage the battery if it is used for minutes nonstop? If I want to use a car battery, is it necessary to do some changes in the magnet? Thank you so much 😀
if you had two of your powerful electromagnets would that double the magnetic force by attracting each other. say 600lb x 600lb squeezing on each other at 9a? was thinking might make a good general press comparable to a hydrolic press. what are your thoughts? if you could get 1200 lb of pressure that would be amazing
Can you reverse it and make a repulsive magnet? Put something on top and see if you can make it look like its hovering? Increase and decrease the current iin real time to make it go up and down? I would like to see that if its possible.
One main reason I keep enjoying your projects is that you do a great job explaining step by step process involved even in the most basic things. Great job sir.
Hi thanks for a very informative video. I do however do not agree with your indication of the magnetic path. The magnetic fields will split at the centre pole and flow the the other two faces generated by the cut you made. If you lay the magnet on its side on a piece of paper and energise it lightly and then sprinkle iron filings on the paper the filings will align with the field and you will be able to see where the magnetic path is.But none the less I think it was a cool video and was presented in a very logical manner. Thanks very much
Louis
Correct,, that's why I enjoyed that project.
Good job.
Gardening with electric and magnetic?
Thanks your information ❤
Something about this dude just makes him enjoyable to listen to and learn from.
Grinding, drilling, clamping, mill work, dent pulling, project or heavy material transfer, lock and that is just off the top of my head. Great video
Yup , a magnetic chuck.
Not sure if someone has already pointed out this minor detail, but I will go ahead and do so: when he drew the magnetic field lines for the transformer after being cut in half, the field lines should have actually gone from the middle section out towards the two open ends of the transformer at the bottom, not towards the closed end of the transformer on top. The vast majority of the flux goes in and out of the open ends, not the sides or top. You will notice this if you try to stick some iron on the top of the transformer- it will not stick nearly as well as on the open ends at the bottom. Very cool video though, and nice way of illustrating things!
Magnet in middle> magnet on-under
Energy flows in the path of least resistance. Therefore the flux will take the straightest path from the copper the iron core because the air presents higher resistance to the flow or current produced by the power supply. Energies natural state is to 0.
@@buckaroundandfindout Yes, the magnetic field will avoid going through the air any time it can, but if you put a gap in the path of the magnetic flux like in this case here, it will go through the air. The two ends have one pole, and the center has the other. The magnetic field is trying to complete the circuit between those two poles in the most efficient way possible, therefore it will come off the ends like I described. Any other path would be longer than that.
@@HeyChickens constructive Central pedal divergence is what you are referring to. Yes some flux lines will flow through the air because there's no room for them in the path of least resistance. Especially in the case of an electromagnet where the force is being pushed into the dielectric field thereby forcing the internal forces to become external. Gaussian flux is introduced to a piece of steel in which it is changed fundamentally on the molecular scale therefore allowing a bypass of the flux fields in what is known as counter space. Where you see the flux in a feral cell is usually the path of least resistance ergo where the force is not located in the flux line. The force is in the space in between the flex lines, that is where you will locate the bulk of the energy that is being displaced via the lack of pathway in least resistance.
Furthermore magnetic attraction is a little bit of a misnomer as far as the words and language describe the actions. It would be more accurate to say that two pieces of metal rushed to a null point that is a convergence of flux lines in relation to the spin of electrons due to the polarization of rare earth metals. Ergo Force equal to attraction is acceleration to a null point.
Enjoyable video, I wish my Electrical Engineering tutor at college 60 years ago had, your interesting approach about magnetic flux.
We just had roofers replace the shingles on our roof and I was thinking of how I could pick up all the nails that where left behind. Something like this with a lite weight battery on wheels to go over the ground and rip all the nails and metal from the soil would be perfect.
Very impressed👍When testing heavy loads, make sure to insert safety link in both directions (use slightly loose rope), if the magnet fail at 300kg or more, the steel block will hit the car and the magnet can hit you with a great force, be careful!
Yes! Newton's first law of motion comes to mind, "Every action has an equal and opposite reaction". Yo certainly don't want that magnet flying off and hitting your shin, that would break both tib and fib easily
Put different sized nails into different types of soft and hard woods at different depths and see if you can devise a practical electromagnetic nail puller.
yooooooooooooooooooooooooo
This
Nails have so little surface area for the magnet to lock onto, it would be virtually impossible to devise an electromagnetic field (out of a microwave transformer anyways) capable of pulling a nail out of wood, especially hard wood...
Everyone else on the planet would've drawn the magnet on the whiteboard with North on top. Not a Kiwi!.. Great vid, long time sub. Keep 'em coming!
hmm.....like this is as if a great suggestion 😅
@@mvnar What?
Great and useful project. I'm a woodworker with a good quality cabinet saw. I use two electro magnets in a wooden feather board to guide my work through the saw instead of using my hand (for obvious reasons), I can position the feather board anywhere on the cast iron table to fit the work I am cutting. I wished I had seen your vid before I purchased the magnets from Aliexpress. Going to build your drill press vice next.
Very informative video and it gave me great info on which type of voltage/current to use. Here's a project that I'm starting to work on. I go prospecting for gold out here in Arizona and we have a lot of " black sand " in our good paydirt. I'm taking a 4" pvc pipe and going to tape/strap 2 of these on either side to pour the dirt through so the magnetic field will "stick" the magnatite ( black sand ) to the sides and let to paydirt fall through for further processing. Challenge is to build one of these and post a video. Thanks again and I'll post pics when I'm done.
Good luck with that I'd love to see that project working !
9:19 the magnetic field lines are wrong. Only the cut part will expose the field lines.
The field lines will still VERY MUCH prefer to be inside the iron so the south pole should be extended to all of the remaining iron. The field lines in air will simply jump the gaps from the central exposed iron to the two ends. From there they will be inside the iron for the rest of the loop. Also, in truth, the poles are only at the end surface; inside the iron the magnetic domains realign to cancel the field almost completely.
Indeed, big majority of the magnetic flux will prefer the magnetic core while there will be negligible leaking flux through the air.
don't bother about the lines
just try understanding his effort.
I will use it to load heavy pieces of steel Into my lathe and mill with my jib crane. Awesome video with how to and verification! New subscriber!!
So what if you replace the secondary coil with another primary coil in an MOT? You would eliminate having to chop off half of the block, but would it double the power? And would you connect the two coils in series or parallel? And would you reverse polarity on one of the coils? Would it matter in AC, DC?
Sorry about all the questions. 😂
Well I know you can't reverse polarity on one of the the coils, you def want the same, but that a good Idea if you have 2 of the same broken microwaves. Lol. Not sure if parallel or series would create a stronger magnetic pull. Im thhinkin series cause more amps
I had the same question couple weeks ago... after cutting a mot into the E shape I placed another coil on top of the primary coil.. connected 2nd coil to the leads of primary flipped the switch and POW!! i thought fk it blew up .. then simultaneously heard a loud thud and something hit the top of my right shoulder... the 2nd coil I placed on the primary coil shot straight up off the mot transformer.. broke the wires off itself as it headed for the ceiling.... I was dumbfounded to say the least ..
@@codyramos3200 I knew there would be polarity issues, but didnt think about the power involved if connected north to north. Yeah, i guess it would do something like that. Did you try reversing the wires?
@@siggyretburns7523 uh I can't say if I did ... I soldered 1 end of the 2nd coil to another coil to make 1 large coil to work as a secondary coil for a step up transformer... it takes a ridiculous amount of wire to go from 110v to 550v ..
I’ve seen loads of videos on microwave transformers converted to spot welding transformers, but this is the first time I’ve seen a conversion into an electromagnet. Nice work! 👍 I’ll give it a try myself.
Yup, a storm's power surge took out my microzappr, I knew there was a good size transformer in it and cut two groves with an angle grinder. Having an old truck battery
with external cell connectors, I can use at 6 or 8 volts and not overheat the primary coil.
@@raymondgarafano8604 I could not find microzappr online. What is that?
@@headbanger1428 a microzapper is just another term I use for a microwave oven,
that's all, Maybe I should have called it a micro-doo-hickey, a micro thing-a-ma-jig.
There have been dozens of copies all the same for years.
Pathetic.
@@โนรีคอกเบิร์น Replies little man to a comment of 3y ago when there wasn’t.
Keep reducing the power supply to the magnet ( volts and amps equally ) to see at what point it fails at 300 kg's, then find your wattage from that and divide it by 300 kg's to see your watt strength in Kk's lifting power. Great video, well made and informative, would never have guessed that a low resistance in the system would make such a difference.
That's a surprising amount of holding strength for such a small magnet. Maybe it could be used with cart type frame for a rolling gantry to move things around.
Best explanation on RUclips! Love the Brit speak. Bob's your uncle!
E-magnets are better for reaping/tearing uses than for lateral/sheering. Just think of those permanent magnet pickup clamps; when you turn them off you basically rotating the load to short the poles...
What was the temperature of the winding after a few minutes? I would like to know the result of reducing the current to see when the 300kg is released.
That's actually a really good question. I also would be very interested to know the answer.
Yup. Third that. What was temp° and could you please do a reduction in current + a fixed weight # so a ballpark value can be determined! :) thanks lots. Great channel and good on you!
Very usefull video. Thank you. Please try to compile a temperature curve e.g. for 30 minutes of metal machining. Somebody in other video checked the different voltage for input - 3V, 5V, 15V etc. Suppose max weight of metal machined piece cca 10kgs. What a appropriate Voltage by relevant temperture? What about a dBA or vibrations during work?
Wow, very impressive cuzzy bro!
Just one bit of feedback and maybe someone else has already pointed this out, don't have enough time to read through all the comments.
That is in your explanation of the magnetic field path in the cut core, you've got it going from the center limb to the back of the core when in reality it is the same path as in the uncut transformer, via the left and right limbs of the core. You can confirm this by checking the magnetic strength at the back of the core and you will see that it is just as weak or very close to that around the uncut core. 300kg plus, holly sh....t!
Keep 'em coming, great video and very enlightening.
Cheers and stay well from across the pond.
I've watched two videos on magnetic vices. One created a "magnetic table" that holds the work with the vice mechanically attached to the table. The other used the magnet to hold a traditional type vice to the table. Both have advantages. If you want to get really creative you could try removing the other side of the core as well and see if the drill press table would work as one side of the core making a magnetically held magnetic table. 😎
Good to see that I am not the only one obsessed with magnets!
I couldn't help myself - I made a video on my channel several years ago. You have given me a few more ideas......
I have several microwave transformers that might be taking on a little transformation themselves 😁
Next term I will be teaching night classes on automotive electrical subjects. I drag around a rolling trolley with heaps of wire and you guessed it.....lots of permanent magnets as well as electromagnets to show students how solenoids, motors, relays and other tricky electrical components work. I usually use a rotor out of an alternator as an electromagnet to show magnetic strength holding a solid shaft of steel, but your idea might be a good alternative (excuse the pun) option!
Keep up the good work! 👍
G'day from 'Across The Ditch'
MiracleMAX
A very good combination of theory and application, well done!
One thing though: with a cut up transformer, the vast majority of the magnetic field lines go from the center bar to the side poles, not around the transformer (9:32). That's what causes the field loops to be closed when an metal object goes across.
If cutting 2 slots and leaving it full size better than cutting it down as all clips shown? More iron larger surface area? Slots cut also would be nice flat and more iron to stick to.
You could make an electromagnetic door lock. Also, the reason I am studying magnetics is to make a large magnetic lift for scrap metal. I think you very much for the ideas I have taken from your videos. Great job.
The commercial magnetic bending brakes are using 220 volt electro magnets generating 6 tons force spread out over 48 inches to secure material. Would like to see what you could come up with!
Thanks, can you give links for more info in these brakes? More abt the winding and core sizes ..
wow, i had not expected that strength with only a bench power supply. I was thinking about making a big electromagnet from scratch but when you can just grind away the weld on an MOT to have a super good one at hand, that'll serve me a lot of work.
9:21 nope instead it have to travel just to the outer side of the E core because it's the closest magnetic path
This video must have million subscribers already... it is very informative!
@9:12 are you saying that the magnetic waves can be compressed and contained in the case and essentially shielded?
Bit of a worry using KNOTTED straps = points just waiting to break suddenly! I would have used some 10mm polyprop rope, but that's me.
Q: What might be the difference in magnetic force under identical circs, but WITHOUT removing the excess laminations?
Also, I'd have been interested to know how warm those windings got after a few minutes of 12V@8A.
Really...you do have very professional welding skill. Thank GOD ....yes you do have! 😇
Love your videos. Today I started a project to build a tape demagnetiser for old Video8 tapes, audio cassettes and reel to reel tapes. I found a good looking design and tutorial online that repurposed a Microwave transformer. I found a 240 volt LG Microwave oven with a primary winding rated at about 9 amps and pulled out the transformer and micro-switches. After removing the secondary winding as you have done I was left with the primary winding intact which I tapped up to be flush with the top of the core face like your electromagnet. My question is, I cannot get any DC resistance reading on the coil, not even .01 ohms. I cannot see any damage to the coil causing a short. I wired the coil in series with a 40watt incandescent globe which turned on normally, (not a good sign I think) I'm nervous about putting 240V across the coil in case it is indeed shorted. I suppose I could put a variac in front of the coil as well as an isolating transformer (I have a 1KVA ISO transformer) to help upsetting other electronic equipment if it violently trips my RCD. My other option is to wind a new coil. What do you think?
Interesting. A New Zealander from the Southern Hemisphere places South above North on the magnet illustration. I wonder if that is typical? I've always seen North above South but I'm from the US in the Northern Hemisphere.
Love the way you explain what your doing !
Awesome video I enjoyed it… hopefully everything is cool down there in New Zealand looks like you guys are on lockdown over one single case! No deaths! Better days ahead ❤️
Something of note that could be relevant. Magnetic field is proportional to amperage times number of turns (plus or minus difference of losses)
A 200 turns at 4A electromagnet will have almost the same strength as a 400 turns 2A one. Only case by case differences will make one or the other slightly stronger.
Well, there are other factors to take in consideration when choosing one over the other, such as power loss into heat, thermal properties,... but that is more relevant when winding an electromagnet from scratch. The point here is to use easily available material and minimum complexity of modification. Which microwave transformers fit perfectly, plentiful, cheap and easy to power.
If you don't mind a question: how can i determine the max or correct amperage to run thorough a primary winding? Can i use the labeled values on the transformer? I also have a question about height of the legs on the "E" frame the windings are in. Is there a sweet spot in relation to the ark of the magnetic field for an increased gauss value or just closer is better? Lastly since the magnetic field is the same at each pole can I use plates on the side and leave both poles ooen to have the ability to hold items on top as well as hold the device down to a metal surface as needed for a drill press? Thanks in advance for any illumination you might care to offer.
Great video man! You clearly put a lot of effort in it, and it shows. It would be a great electronic lock for your workshop. Not at max current, that would be too harsh for the winding. Or if you make it waterproof, it could be a great magnet-fishing device. Power it up with a car battery. And I sure can use a scaled-down version to get the thousands of tiny screws and bolts out of my long fibre carpet.
+ 1 vote for next video to make a magnetic chuck or vise!
😃 he did it
Great video, excellent descriptions! I'm wanting to build a trommel with an electromagnet Incorporated at some point to remove nails from wood ash.
Thank you for posting!!!
SCHEMATIX
Hi there.
How could I know which is the North pole and South pole in an electromagnet????
Thanks for answering my question...
You can either work it out from basic principles or, even easier, test it with a permanent magnet like a compass. :)
@@Graeme_Lastname
I like good answers !!!!
Thanks for explaining me, however ....could you please say more about 'basic principles'?
Thanks a lot in advance.
@@isabellemarquez4806 Basic principles give you, among other things, the direction of the magnetic field when the direction of electron flow is known. Way to much info for a comment post. B well m8. :)
In other words a transformer core contains all the field, as long as the core isn't saturated. Thus external iron doesnt interact with the magnetic fields inside the core. But where the field exits the transformer core, they can interact with external ferus metal.
The field lines are are in a close circuit.
The horse shoe magnets would be having pole pieces when stored for long time.
The torroid core design assures self shielding meaning any other torroid core transformer can be placed just beyond half the diameter distance of the bigger one.
In the case of a solenoid winding to minimize/ avoid interaction the coils would be placed perpendicular to each other and in the case of a third coil, it would be placed in the vertical plane.
You can observe this in the radio circuits.
@@subramanianr7206 if one rewatches the video 5:14 , the original core before being modified was expelling some magnetic fields. That's indicates over saturation that inturn indicats one should run fewer amps due to the fact that the rate of increase in the magnetic field drops due to drop in a decrease in permibility.
en.m.wikipedia.org/wiki/File:Permeability_of_ferromagnet_by_Zureks.svg
But, on rexamination of transformer design, i might be wrong on the saturation current after the core was modified. Transformer design sometimes introduce an air gap to increase the saturation current level. Cuting the core in half introduces a large air gap in the magnetic circuit. Presumptively, that will also increase the saturation current level, maybe well beyond 4 amps. The large air gap now allows for using the core as an electronagnet. But when a piece of metal closes the air gap, the saturating current level will drop.
Take away is that there are more things to consider what current one wants to run depending on the core and how one will use it.
Your experiments flow just as i would do them myself, thanks for the detours
The magnetic field is proportional to the number of turns times the current. Since you are using DC, the larger number of turns in the fine wire coils would have needed less stress on your power supply.
Yes but it is also proportional to the current IIRC. So if he was able to increase current more than he was able to increase turns, this was the way to go.
His risk on going to small turns was that he would have to lower current to avoid overheating
Excellent demonstration of exactly the kind of info on electro-magnets that I was looking for. Thank You! I will be watching if you decide to utilize AC power in demo and it will be interesting to see the pro's and con's of DC vs AC with powerful electro=magnets.
Correct me if am wrong. Electromagnet is demagnetizing, while natural magnet magnetizes ?
You can limit the current, from an AC source, by using use an AC capacitor, on the hot AC lead of primary, and using the Capacitor Reactance Formula to calculate in Ohms.
AC cannot be used to run a electromagnet. Maybe not what you're saying, but the more you know
@@OtherDalfite Wasn't what I was saying. I assumed you would use a rectifier, but, before it gets to the rectifier, you can limit the current using a capacitor on the hot AC lead using capacitor reactance formula.
Example:
108 UF capacitor limits the current due to Capacitor Reactance
Capacitor Reactance = 1 / (2 * PI * Frequency * UF / 1000000)
EX: 1 / (2 * 3.14 * 60 * 108/1000000) = 24.57 Ohms
120 VAC / 24.57 OHMS = 4.88 Amps
You could put half the current through the magnet and assess the break strength there , or a 1/4
Different steels have different magnetic saturation points, where the magnetic forces pulling towards the iron core is drastically reduced per amp going through the windings. If this point was reached at say 80% current draw of what he is drawing in this video, and then half the current to take a measurement. you only had a 20% drop in magnetic force but half the current draw, thus giving a false measurement. (These numbers are straight out of my ass, and only to prove a point)
very cool. so small yet so powerful. I made an electromagnet using a 65-pound steel bar and about two hundred feet of insulated copper wire. then hooked it up to a 12-volt deep cycle battery. it was strong, but not as strong as that little one you made. And it got hot quick. Thanks for the perspective. Ill change my design. ; )
I thought u were a Brit but saying 'Bob's ur uncle' confirmed it. U do a great job!
His accent is definitely New Zealand, not British.
‘Bob’s your uncle’ is regularly used in lots of countries, including here in Australia.
Great video. I am trying to build a seriously powerful electro magnet using the microwave transformer. My question is, rather than cut the excess metal off of the ‘E’ shape, could I install an additional coil winding (1 or 2) from a second and/or third disassembled transformer? Installing 2 or 3 windings on the inner ‘E’ part. Then wire in separate winding in series from the power source with a switch. It is my understanding, the more winds the stronger the magnet. Any comments are appreciated. I plan to try and power this off 2 older diesel truck batteries wired in series for a 24v power supply.
Schematix, I believe that welding the laminations together weakens the overall magnetic field. There's a reason they have them split into several individual pieces.
Don't matter for DC but AC causes problems, at least that's what my prof told me.
@@Graeme_Lastname you might be right. I know it's done for transformers to increase magnetic flux so less losses in the core occur.
@@OtherDalfite Basically to eliminate induced currents flowing in the core which would appear to the transformer as a shorted turn. ;)
@@Graeme_Lastname right, to reduce eddy currents flowing around in the core, much like how an induction heater heats up the "core" of whatever iron or metal is inserted inside the coil.
So essentially this wouldn't affect a DC magnet situation because the core is never experiencing any eddy currents since the direction of flow isn't changing. So welding the laminations doesn't affect anything. Correct?
@@Graeme_Lastname Why fragmeted magnetic core in DC machines?
Nice, use to lift megalithic blocks in chain out of a quarry the way Ed might have , seriously, it is amazing for the current used.
So number of turns increases flux too. How about cutting another transformer in half and comparing the flux of the high turn, low amp side against the low turn, high amp side?
Make a portable wheeled card electromagnet for wheeling over the yard to pick up miscellaneous screws and nails. It'd be cool to make one for separating black sand from the other sand.
You can double the range of your measuring instrument by using a simple tool called a 'snatch block' which consists of a single pulley, You will have to move the cable running thru the snatch block twice as far as you would be moving the load, but you would only be using half as much force to move it.
Just measure that force and multiply by 2 to double the measurement range of your instrument.
That would overcurrent his peabrain.
Your video is great, you don’t just explain things really well but you jump in with everyday practical experiments we could all do. That is really powerful and to think it came from an old microwave transformer too, I will use this on my own project, thanks
I want to know to how extent can the coil withstand the heat generated in it? great great your effort
thank you for not blaring music thru-out video
wonderful explanations
That really helps me understand how magnetic power works thanks for the great vid 👍🏼
Excellent. This was fun. Two questions:
1. Why 0.5 to 2.0[ohms]? Is it ONLY about what resistance across the fixed DC source voltage which allows the desired peak current?
2. What type of supply was used in the second (car tow hitch vs. steel pole) test? Was this also an adjustable bench top supply, but with higher current capability?
3. What happens if you hook the coil leads to an AC source, eg. a 120[v] (rms) from the wall plug?
OK, that was three questions.
Thanks again. Very educational.
Quick question about when you cut away part of the core and it was still an intact transformer. In addition to the field mostly interacting with the core itself, wouldn't you also have some loss due to the other coil? Or would that only effect it if there was a complete circuit with a load on the other coil?
Magnifique Monsieur. Merci pour la vidéo.
Great ... The pulling power was truly amazing
Would you tell how many rounds of the coil, how big the wire and how many voltage do you used to have such a strong magnetic. Thank you.
Excellent video particularly on ease of selection of the transformer. A very cheap mag drill is in my mind I always wanted, and, what I really want to do is a cheap method to have a kill switch on my digger I need to be activated by trips for safety where the "real thing" dam near costs more than the machine. (the magnet will hold the fuel shut off open and another can similarly lock my hydraulics simultaneously on the same electric circuit). Thinking that much power would also work as a lock on the slew control (it's the real one that kills people tripping or catching clothing) in a circuit where if it's not locked the fuel and hydraulic one power off). Been trying to find a way to do this for ages.
great explanation. Wish I had you when doing my apprenticeship. Got there in the end haha. Looks like you could have used an electromagnet drill vice at 6:19... What about an electromagnetic drill press bed so you don't have to use a vice at all. Still looking for something similar for aluminium too...still looking
woow Bryman i really happy see all hobbyist engineers using over expensive flukes
Speaking of saturation. Seeing the core expelling some magnetic field at 4 amps means 4 amps is too much magnetic field for the core and you have saturated it.
You should have dialed the voltage down to push less current through until your under saturation point. Then you can cut open the core.
Pushing more current passed saturation does little to add to the magnetic field past saturation. Thus the extra current does little more than create heat and unessesarily waste energy.
(Added after have posting to include new information and avoid confusion) sometime
Transformer designs include an air gap to increase the point where current saturates the core. That said, cutting the core in half introduces a large air gap which could presumptivly push up the point where current saturates the core to well beyond 4 amps, but if one closes the air gap with a ferrous metal, it will lower the saturation current again.
Takeaways: There are more things to consider when determining what is the ideal current for a given core and how one intends on using it.
Woooow!!!!thats awesome!! That was completely counterintuitive for me.thank you sir.i want to try it with circle core.
I have an idea/question. What could you pass over the magnet to disrupt the field and how much control could you have over it? My idea is to have something like a strong magnet at the base, with something to disrupt the fields set above it. Above that I want a tray filled with ferrofluid. I want to see how much I can control its dance via altering and possibly reshaping the magnetic field. I have a degree in electronics but my courses merely had the minimal obligatory mentions of magnetics so I'm just playing to see what happens.
I’m looking at building a system for our Jib crane at work to act on a switch to act as a brake system to hold the trolley in place (to a point) and possibly the swing
MMF is measured in ampereturns. Thinner Wire equals more turns so the heat developed is independent of the Wire thickness
Big with ups to you for this education , thanks heaps. Your education skills are great with your presentation with details the most important. thanks
Thank you for this informative video ! I surly could use the electromagnet that you demonstrated, to pull dents out in autobody applications ! The setup that you have would help me GREATLY in repairing my truck !
Won't work. It will saturate.
Great video, good narration and not annoying like some. I came here with the same idea you had, of making an electromagnet vice :).
That's a really good video, the best one I've found on that matter. Thank you so much. I need to make one or more of these in order to make a magnetic table for cleaning plasma cut parts. I'm a bit worried about it's electrical safety. Is there something I should do in order to avoid someone getting electrocuted in a magnetic table fitted with some of these electromagnets? Is just grouding the table enough?
I'll never look at an old microwave the same again, thanks.
Thank you for making this video, very interesting indeed. It would be wonderful to know the maximum weight your powerful magnet can carry.
good boy.....same as i use...angle grinder/chop off saw (homemade from furnace motor, and microswitches from microwave).....to re-create MOTs for chargers, welders, etc. made an 18 volt dc supply for cordless tools, converted to corded tools, ...mots rewound for 19 volts dc with capacitors and bridge rectifier.....all work wonderfull....good for you...
I can't help thinking that by welding the laminates together you reduce the flux density of the core as all the plates are now connected. Perhaps a better way might have been to give the outward faces of the transformer a coat of epoxy? Or even powdercoat it?
I didn't see any comments about the mistake in diagram @9.21 I am confident this is secondary school science stuff....and unless I missed the reference to a basic magnetics concept...i.e. no mention of ampere turns vs flux density ... Schematix is testing you....and you didn't pass!....fun use for a microwave tranny though....and what degradation in lift performance if the legs of the core was left as it was initially cut with angle grinder...as I suspect that not that many have a metal cutting band saw ? Thanks for the great idea and future project !
The diagram at 9.21 is absolutely correct. If you want to find out a mistake it would be that he had not marked the arrows on the lines to represent the direction of the convention; but surely he was drawing it from the N pole to the S pole.
In the whole transformer the field lines are closed.
When the pole piece is exposed by cutting off it keeps attracting the iron with a heavy force.
You should refresh your school physics, I believe.
@@subramanianr7206 The diagram shows lines of flux without any effect of the core. Are you saying that the core has no impact on the concentration of flux? If so then I suggest I am not the one who needs to refresh school physics!
What if you made like 10 of these and attached them to the loader of a tractor? Curious as to how well it could find old nails and screws for construction site clean up.
How about lifting a very heavy old tube radio or test equipment up to a work bench.
As long as there is enough iron on the cabinet; but most of them had wood work.
What is the simplest way to make a small magnetic table so that i can make a small surface grinder about the size of an a4 piece of paper. My financial resources are very limited since i have spent most of 20 years in bed. Most of my metal and wood is what i find near the local garbage dump on each block close to home. I really do not understand electricity though i did completely rewire my house in new york 40 years ago.
Thank you for your time and help.
Very informative video .
Sir , thank you so much for sharing your knowledge .
I am from Sri Lanka .
Very nice demonstration but I have a question. If you have 4 components like that, can you link them together like in series? What will be the result, please?
Though difficult to measure the absolute force, I would like to see the performance of two equal EM's, one with a timed momentary current supply mounted stationary above the other mounted atop a piston connected to a crankshaft with a momentary, timed commentator current supply. The crank mounting apparatus (block) and stationary (head) mounts of aluminum so as to not interfere with magnetic fields. Ideally, the timing and supply current electronically controlled with opposing currents supplied at the top dead center (TDC) of piston travel. Once in motion, supply current can easily be generated from the resulting crank rotation or through pick-up coils in the cylinder walls. In theory, the instantaneous opposing magnetic fields of the magnets could produce a force, however marginal, similar to that of internal combustion. Furthermore, this force could be produced on every rotation rather than the 4 to 1 of a gas engine. Obviously some engineering to work out, but feasible, don't you think?
Great Video, excellent work. By the way, what was the AWG size (wire diameter) of the final coil you used. ??
That is very interesting...
!!!!!-----> You can get a higher weight reading off your scale there. use a pulley system and then multiply the reading by the ration of the pulley or a falcrum.
With the falcrum you it is basically by percentage. if it is in the middle then it is 1to1 if 1 third down then its 1to2. Then use the scale on the 2x side and magnet on the 1x side and if you measure 300 then its actually 600 strong.
IF all else fails...How much does the car weigh and are you insured?
I love your channel. You are good at explaining things. Also I love your accent and sense of humor. Keep up the good work!
You could use your microwave electromagnet for the base magnet in a mercury vortex drive; so, you can vary the field strength and direction giving you additional control over the vortexes rotation.
no
Good explanation....but what will happen if I use ac power?
Awesome advice and well presented! I learned a lot. I do have one piece of advice. Next time don't heat the laminates in the core. They do have lacquer on them for a reason. Laminations perform better in a transformer core than solid iron or molded ferrite powder. It's important for the laminates to be separated from one another with the lacquer. If they touch one another conductively it reduces the efficiency of the core. Next Time start with a new core that will not be damaged by taking it apart or welding all the laminations together into a solid conductive core. In the least don't weld the laminates together. Perhaps put it into a vice while applying some two part resinous bonding glue.
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So how does the liquor get the laminations of those cores that are welded already
@@richardsellars8598 I used the term lacquer but I dont know what material engineers use to isolate the different laminations. I only know that it's a proven fact that isolated laminations create the least resistant transformation. You'd have to ask an engineer how they manage to retain isolation because i dont know.
I needed a such Electro Magnet for an innovative project and the one you introduced was nice.
Does it work with a car Battery?
Doesn't it damage the battery if it is used for minutes nonstop?
If I want to use a car battery, is it necessary to do some changes in the magnet?
Thank you so much 😀
Great video! Thanks for posting! Do you know what Tesla measurement is this magnet is achieving?
if you had two of your powerful electromagnets would that double the magnetic force by attracting each other. say 600lb x 600lb squeezing on each other at 9a? was thinking might make a good general press comparable to a hydrolic press. what are your thoughts? if you could get 1200 lb of pressure that would be amazing
of course
The ideas are endless so many possibilities
Can you reverse it and make a repulsive magnet? Put something on top and see if you can make it look like its hovering? Increase and decrease the current iin real time to make it go up and down? I would like to see that if its possible.