To make a strong electromagnet you need to keep the following in mind: -Make the core out of a high permeability material such as iron. The iron wire in a coat hanger works well. -Use many iron wires side by side to increase the area of the core. -Use many turns of large diameter copper wire in the coil. -Make the core into a U-shape so that the north and south poles are very close together I can create a video demonstrating these techniques if it will help. Thanks for your interest..
Hello Dorian. Could you please send me a video for the electromagnet core made by hungers , I would like to try it, If you don't have the video please send me the diagram or scetch or even explanation how to do it. My email nafim712@gmail.com I really appreciate that
AA battery when gets connected to MWT primary winding draws 2.6 Amps x 1.5 Volt = 3.9 Watts of power is used. Guy's, do you see what's going on here? This is a over efficient machine. You turn this electro magnet into a some kind of pulse DC Motor and you are going to get much more power than 3.9 watts! Dorian, you did a great job man, thanks for making this video.
Vic, the science is all about making improvements on technology that uses less energy and does more work 4 U. Lets take a look at the recent advancement in light technology for example: (equiv. 60 watts) it takes 10 watt Led = to Incandescent 60 watt. Light bulb projected lifespan: Led 50,000 hours, Incandescent 1,200 hours. If you care to learn more? Please use these key words: LED Light Bulbs: Comparison Charts.
Be careful. Holding two objects together does not require energy - it only requires force. If I duct-tape two object together the duct tape is not providing energy to allow this to happen it is providing a force. Energy is involved when a force acts over a distance. The electromagnet must be in very close contact to the object it lifts, it can only pull the object upward when the objects are essentially touching - so very little energy is involved. The energy required to lift 50 lbs (22Kg) 0.1 mm high is only about 0.02 joules - which is not much.
Electromagnets can create very large magnetic fields and forces when objects are very close together. Unfortunately the AA battery must supply about 2 amps of current and will not last for long.
When you say "it will overheat in a few minutes" can you elaborate on that? What will over heat? The battery or the magnet? What happens if the electro magnet overheats?
i never thought i can build a home made strong magnet until i saw this video. so simple and straight forward! INSPIRING! thank you for the upload. keep it up.
Hi Javed, If the oven works the transformer is obviously good. If the oven does not work the chances are that the magnetron is bad but the transformer is fine. I have not found a bad microwave oven yet with a bad transformer. Checking the coil in the oven will require you to gain access to the transformer, removing one of it's connectors and checking the resistance of the primary coil (fewest turns). My coil has a resistance of 0.5 ohms. Hope this helps. Feel free to ask other questions.
Thanks Dorian. You helped me a lot. I study and research calculation and I found out that Gauge 16 is the most efficient. It has very low resistance so I can make lot of turns as compared to smaller wires. Thanks again for wonderful video.
Cool thanks! it gives me an idea to make electromagnets for some Halloween props. Wouldn't want to use Relay's to turn the magnets on because they are usually noisy so wondered about using a switching transistor. I will have to look at a flyback diode to see if that would protect the transistor.
Stephen, Make sure you use a fresh battery capable of providing the large currents required by the electromagnet. A 9 volt battery will not provide enough current to do the job even though it has a higher voltage than a AA or C cell. 9 volt batteries are designed to provide higher voltages not currents. You will need a small motorcycle battery or car battery if you really need more power. Also make sure you use heavy wires to conduct current from the battery to the magnet.
Its not important that the coil touch the metal. Be careful not to remove the insulation on the wire. The wire is coated with a thin transparent coating that keeps the copper in the wire from shorting together.
This is an amazing video. I never thought about transformers in that way but after watching this video, it was like a light bulb went off and I said, "duhh". lol When I saw this I immediately went to my basement and tore apart one of the microwave transformers I had and built that electromagnet in 30 mins. It is soooooooo simple its awesome. Videos like this inspire others.
Great! I'm very happy that you found the video inspiring and particularly impressed you built the electromagnet so quickly. Thanks for sharing and commenting and have fun showing it off.
The reason you get a heavy spark when you disconnect is this. When you connect the power, you get that very strong field built up around the core and coil.This very strong field is what lets you pick up very heavy items. When the circuit is opened, all that magnetic field that was built up around the coil and core suddenly collapses right back into the coil that made the field, to begin with. This is 'back voltage. It is EXACTLY why a condenser was placed across the points in gas engine ignition systems, be it a battery and coil or, a magneto. The condenser absorbs the back voltage and keeps the points from burning up.
Stephen, Did you use a microwave transformer for the core? The trick to lifting heavy objects is to make sure the objects you're lifting are very close to the electromagnetic. Magnetic fields do not travel well through air because the permeability of air is very small compared to the permeability of iron and other magnetic materials. Even large junkyard electromagnetics have to almost touch the material they are lifting but they can lift very heavy objects if they are in contact. Good luck
No, This electromagnet is much like a junkyard magnet. It can pick up large loads in good contact with the magnet. Read the companion information for details. A rod-shaped electromagnet will pick up objects further away but with less force.
From 1,5v thats amazing, I would never have thought that much force could be available....12v/9ah battery would give how much force then ?..Lift a car almost. How can you protect the battery from over heating, because this circuit is basically a short circuit.?....Nice video, I subscribed to your channel.
Higher voltages should only be used for short periods of time to keep both the electromagnet and the battery from overheating especially when using higher voltages. You are right that the coil is essentially a short circuit, or at least a very low resistance (about 0.5 ohms), so things can get hot quickly if the current is sustained. Thanks for commenting and subscribing.
Dorian McIntire Thanks for your reply....In your experience is there an optimum coil size for say 12v/2amps supply continuous..without everything getting hot.
MrFreddiew1 The interactions between coil turns, coil wire gauge, resistance, power dissipation, current, voltage and power supply capability are pretty complex so I'm not aware of any formula for optimum efficiency. The simple rule of thumb is to use the smallest gauge (largest diameter) wire you can find, use as many wire turns as you can and pass as many amps through the wire as you can without overheating your power supply or magnet.
Looking at only direct current in a coil, all copper coil will have some DC resistance. Current is i=v(voltage)/r(resistance) , Power is watts = i * v. Given that i = v/r, watts is also expressed as w=v*v/r or w=v^2/r . The resistance will change a little as it warms up, but for the most part and for simplicity we might assume the resistance doesn't change. putting that together means that as voltage grows, amps will grow geometrically to the voltage, and power consumed grows exponentially to the voltage. After the magnetic field is established, all the power being consumed is dissipated as waste heat from the resistance in the copper wire. This slowly heats the iron core. so run times is limited by higher voltage and how fast the core can dissipate the heat. Now without an iron core, a coil's magnetic field strength has a linear relationship to the the amount of current flowing through the coil. A coil with an iron core will have a stronger magnetic field as the magnetic domains in the metal align and contribute their magnetic fields. But it has only so many magnetic domains, and at some point their are no more domains to align and contribute to the magnetic field. this is called saturation. and adding additional current to increase the magnetic field takes a bend growing at a slower rate. Now on optimization. If we restrain our discussion to current below magnetic saturated core, and look at the geometric growth of current to voltage and exponential growth of power consumed to voltage, and ask for an optimum ratio of (magnetic field strength/power consumed) then we might look at lower and lower currents as having better ratio. But at almost 0 current, one would not have a useful magnetic field. In other words, one should probably start with asking what kind of magnetic field does he want, and how to optimally achieve that given a specific application's constraints. Now if you must use 12v you might try pulse with modulation and vary the duty cycle to control how much power is fed into your coils. you may also consider ways to active and or passively cool the coils. One might also try voltage divider. by adding a resistor in series first measure the ohms across a coil. This might take a bit to settle down to one value. if the max current you want is 2 amps. Then the equation is 12 volts /( resistor + coil resistance) = 2 amps, and solve for resistor.
Hi there, thanks for your great video! Very helpful. I was hoping you could tell me how long that AA battery will last whilst in use. Thanks very much, Jo
Probably only about 5 minutes for an "AA" battery but this really depends on how much of a rest you give the battery between uses. A "D" Cell battery will last much longer, maybe around an hour. The electromagnet uses about 1.5 amps at 1.5 volts since it has a coil resistance of about 0.5 ohms. The specifications for a typical battery can be found on Eveready's website. Just Google "eveready technical information" and you will find technical information on all their batteries with charts and graphs about useful life and current capabilities. I use the AA battery for effect since it surprises most people that such a small battery can create such a large force. The key to this effect is that the force does not extent far beyond the magnet. Thanks for commenting.
The wire coil will overheat due to the large currents in the coil when connected to higher voltages. If the coil gets too hot the wire insulation can burn and short circuit the electromagnet. You just have to make sure you let the coil cool before using the electromagnet again.
+Oliver Smithdeal Make sure the microwave oven has been unplugged for while before removing transformer. No other problems as long as you don't go overboard on the battery voltage or leave it connected too long.
+maxxlexx1 it wouldn't be a true perpetual motion engine simply because the amount of energy required to power the motor would be less than that generated by the wheel. With that said, as long as the magnet had power you could turn a wheel, if set up correctly.
The wheel could charge that lil 12v battery and it could intermittently fire it off to keep it going but it still wouldn't be considered perpetual motion simply because of the way individuals define it... something out there could literally run for the rest of a individuals life and still not be considered perpetual motion (wear is sited as one of the reasons). lol
From a microwave oven transformer. Every microwave oven has a core like this used to create the high voltage needed by the magnetron and you can break the core apart using a hacksaw or grinder. I've found lots of uses for these transformers including welders.
Isn't this how electromagnetic security doors work? So there obviously is a safe and efficient way to keep it powered for an extended period of time, otherwise it wouldn't make a very good lock. You could just wait for it to fail and open the door. Also, what other appliance can be used in place of a microwave. Thanks!
Yes most electromagnet door locks work on the same principle. It is very easy to produce very high pulling forces when object are in contact. While any modified transformer will work I have found the microwave oven transformer to be the easiest to use and because of its physical size the pulling forces can be extremely high.
No, a coil alone will produce a relatively weak magnetic field for a given current. To concentrate the magnetic field you need a material with a high permeability like iron.
The secondary has 10 times more turns of wire but 100 times more resistance. Since the strength of the field is proportional to the ampere-turns (current x number of turns) you will get a stronger magnetic field for a given current. To get the same current as the secondary you need 100 times the voltage but your magnetic field will be 10 times stronger since it has 10 times more turns than the secondary. Bottom line is that you will need 10 times more voltage to get the same effect.
Higher current is necessary to increase the strength and this requires a higher voltage. You must make sure your power supply can create the current necessary because some power supplies can provide the voltage but not the current. Too much current will cause the magnet to get hot so be careful not to burn the unit out.
Hi, thank you so much for giving back to the community by sharing your knowledge! It is an awesome video! I have a question about those electromagnetic displays that are sold on amazon and other sites online. I bought one and I opened the floating object and took out the magnet so i can float something else in it but my object is too heavy. How can I increase the weight it can hold?? I would really appreciate if someone could help me figure this out :) thank you so much
a couple of weeks ago I brought home a microwave from the transfer station ,I did know i could use it for a welder or spot welder but I really got it for the electronics . So came across this vid , I was wondering what kind of application can I use this project for. I was trying to find a magnetic door lock . This would be too large for that application. Dorian I always enjoy watching your Very informative Vids.Thanks.
bhavani the core is straight out of the transformer with no modification. Use the winding with largest wire only. Remove the winding with fine wire. Make sure the transformer is a 120 volt transformer and not a 240 volt transformer.
Cool. You said that the transformer gets hot if you leave the current on long enough. Does it get hot enough to melt? Also, if I were to use a 12 volt battery, would it be strong enough to lift 30 lbs from 8 inches away or does the electromagnet have to be pretty close or make contact in order to make the lift? Thanks a bunch and sorry if my questions are any inconvenience.
+AGENT G It will lift hundreds of pounds using a 12 volt batter for a short period of time. Distance is a problem for magnets if you want them to create strong forces. Much depends on the thickness and type of iron and how close it is to the magnet.
Excellent and simple. Can this be adapted where the transformer core is mounted to an iron bar or pipe so it can be used to clean an area of iron like picking up nails in the yard? Also how long might the battery last? Any advanatge to using a higher voltage battery or power source?
Not really since it cannot do it for long. A few of concepts I wanted to demonstrate was the difference between energy and power and how magnetic fields can be very intense over very small distances.
dude my mouth has been stuck open and my eyeballs are pippin out of my head in amazement and excitement. WOW dude what in the world... THIS IS SO AWESOME. Sir, can this me used as a clamping device to glue wood parts together. What is the maximum opening allowed before clamping force starts to fall off? thank you sir for sharing this Im gonna make it tonight..
STIZEN9 use the electeomagnet near the hinge and make the clamper adjustable (with a screw for example), this way you maintain contact between the magnet and the iron (giving you the force) without having the two camper hands in contact.
an interesting fact is that the video cuts as soon as you put the handle/plate back on and that your using 1.2 - 1.7 volts (depending brand and type of battery) to lift 50 pounds plus the bottom plate.
I'm sot sure if your comment is meant to expose some suspicion about the authenticity of the video claims or point out that this indeed works well. The video cut occurred because it took several attempts to keep the weights from shifting on the board while I was demonstrating the electromagnet. I put this video together on a whim and couldn't think of a easy way to immobilize the weights on the board. I didn't want to extend the length of the video by several minute while I was finally able to balanced the weights perfectly on the board so I removed the failed attempts. BTW: The whole assembly was mounted on a board so students could step on the board while pulling up on the metal plate. Even large, male students could not break the metal plate away from the magnet with a fresh battery and a solid electrical connection so my claims are actually a downgraded version of an ideal situation. Many viewer have built the electromagnet. I would appreciate it if these viewer would report their own results. Thanks.
This is great, with lots of great answers already provided below. Many thanks. I already used a MOT to create an electromagnet thanks in part to your video, but I'd like to teach some kids about eddy magnets as well, since they're learning about recycling centers and how they separate things. Is there an easy way to step-down an AC connection so it isn't quite as loud and reduces the risk of tripping a breaker. (I'll still run it through a power strip to avoid tripping breakers at the school.) Thanks again.
If you have two MOTs you can connect them in series but put the iron bar on one of the MOTs to make it act like a variable inductor. You should have the capability of drastically reducing the current and this is adjustable by moving the position of the metal bar on the current-limiting MOT. This is probably the best way to control the current without using a transformer or large power resistor. Have fun.
I have two MOTs, I understand "connect them in series," and then I got lost. I'm thinking that is probably a sign that I shouldn't mess around setting this up on AC, and I should stick with the battery for safety's sake. Thanks again!
Dorian, Thanks for the quick response! In fact, yes, I did use a microwave transformer for the core. But I don't want to lift heavy objects. I actually want to lift very light weight objects (think nails, bolts, etc) but at a distance of about 6 inches. It's for an architectural model/installation.
Awesome video! I want one of these now. >:) Two questions though. 1. Assuming the AA battery is fully charged, how long the charge last, would having a battery pack of some sort (4 AA battery pack or similar that you would find in a TV Remote) make it last longer? 2. Would it be safe to have on of these mounted on a wearable back plate to hold a sword (disconnect the battery, sword comes off, connect battery, sword won't come off at all) or would I be better off making something smaller/weaker? Thanks in advance. :)
+umm36 The average capacity of a AA battery is about 1 amp hour, and the short circuit output (worst case scenario) is said to be between 1 and 5 amps. Now, that's pretty vague, but it should give you an idea. If the magnet draws 1 amp, you'll get one hour. If it draws 5 amps, 12 minutes. Chances are it'll be closer to the 1 amp, since small batteries get kind of hot putting out 5, but I honestly can't say, I'm just speculating. As for the second question, I might be able to shed some light on a safety issue. As far as the magnetic field goes, you'll be fine, unless you have metal rib/back/hip implants, or a doctor left a scalpel in you. The sword however, may give you trouble. Since the entire magnet is oval in shape, and the sword is not a full square, it'll likely try and align itself with the magnet. If you take the sword off and the magnet activates unintentionally, you won't know until you try to put the sword back on, and the magnet will suck the sword towards itself. Once it's captured by the magnet, the force will overwhelm your arm, and you'll lose control of the sword. If the magnet twists the sword the wrong way, it could slice into you or someone around you. It's giving the sword at least 200 newtons, which, given a 1 KG sword, can bring the tip to (roughly) 350 km/h, and that's very conservative. So, if you're going to use a sword, make sure to have it on the electromagnet before turning it on. Maybe use a resistor to prevent the magnet from producing that much power.
umm36 I can't promise that. It could be as little as 20 minutes or as long as an hour, maybe longer. To add to that, if the battery is being drained at a high rate, it could overheat, causing damage and reducing it's life. A resistor might help, since it won't let the current flow at short circuit rates, but it'll also bleed off some power.
The current drain from a 1.5v battery is a little over 1 amp so a AA will not last very long. I use a AA simply for effect so students can see how a small power supply can do fairly impressive things. If you want the battery to last longer use a D cell. You should get about 30 minutes from a AA and 8 hours from a D according to technical information from Eveready's web site. A 12 volt battery will allow the electromagnet to lift over 300 lbs but it will overheat in a few minutes. Have fun.
The AC, and regarding an item, would pick it up, drop it, pick it up drop it, pick it up sixty times a second, so you'd never get anything lifted. If, on the other hand, you were using a AC to DC converter, you'd be off an running.
If you use the secondary wire to supply a current to make a strong electromagnet, could you then take the primary wire to make it into a speaker? A speaker can be made by just using a copper coil and a really strong magnet (and, of course, a cone of some sort), so I don't see a reason (in theory) why this couldn't be used to make an Electromagnetic Speaker.
i have not microwave oven transformer but other same transformer wind 22 gauge wire 50 turns but not work supply 240 volt AC how i make electromagnet ? this electromagnet repeals the aluminium for eddy current create because i will use in making flying board
narcat Thanks for sharing this with the group. I've had a few comments from non-building, critics who believed the video was doctored. I love it when others chime in to put this non-sense to rest. I really appreciate your comment.
Ronald RC Brushless motors work by using electromagnetic force to pull a rotor towards each next magnet and then switch polarity and push themselves away from said magnet in a rapid transition. The more powerful and power efficient the electromagnets are, the more powerful the motor is. If you could position some of these along a rotor with some hall sensors and circuitry to control the polarity, thats possibly roughly 50lbs of force per magnet on the rotor, and if you could power it with a few small cells, holy torque. This would make an AMAZING motor
YSC That was my first thought, someone with better resources than you or I have, needs to collect like 6 of these and make a massive brushless torque monster
The electromagnetic has about 300 Ampere-Turns (100 turns * 3 amps) of MMF. This creates a very large magnetic flux when the reluctance (resistance to magnetic flux) is very low. With the electromagnetic, as long as the air gap is very small the magnetic field strength is very large. The magnet does not need much power to provide a large pull since it is not actually moving the weight relative to the magnet if the weight is in contact with the magnet. Any time you want to create an electromagnet with a lot of pull you need to minimize the air gap between the object you want to pull and the magnet. BTW: This electromagnetic will lift well over 100 lbs with a 12 volt power supply. Thanks for commenting.
Two quick questions, and thanks for the response. I'm in the process of copying your hack for practical use in the field. 1. Should I/can I trim down the leftover core material so that it's level with the winding to reduce weight? 2. Looks like the primary winding is used. Is that the case?
Aaron Baca Yes you can trim down the core but make sure the cut is very straight and doesn't produce any air gaps when the core contacts an object or you will seriously reduce the lifting power of the magnet. The primary winding is the one you want to keep. This is the winding with the largest diameter wire.
Is it safe to go into a microwave oven ( broken down ) and remove the transformer WHAT ARE THE PRECAUTIONS I NEED TO KNOW this is interesting I LIKE THIS TOY
Yes it is safe as long as the oven is not plugged in. There are now other videos available on TH-cam that demonstrate the details of modifying the transformer.
Really cool video :) Can I make a video request? Can you make a video for 1) the optimal characteristics to optimize a 1.5v aa battery and 5v usb (@500mA or 1A) electromagnet? 2) A breadboard or electronic controller for pole switching one or more magnets?
Great video, thanks for sharing, a few questions; how important is the metal base where the coil fits nicely? Also how do you make the magnet to repel the other half of the transformer or any other metal?
Ernesto Del Bosque The metal base is very important since it helps keep the magnetic permeability (sort of like magnetic conductivity) high and keeps the magnet strong. A magnet that repels other metals is possible but such a magnet must use AC power to work. It will not repel iron but will repel aluminum and copper by inducing electric currents in these metals that will create a counter magnetic field. I will show such a device in a future video. Thanks for your comment.
Is there any chance the battery will explode? Or is there a risk of getting shock when taking apart the microwave without it being plugged in? Please answer ASAP
Andre Poelman The key to this feat is that the magnet only has to produce a powerful force. Large forces can be produced with very little energy if the distances are small. Since Energy = Force x Distance and the object is already touching the magnet the magnet does not actually have to move the object. In this case the formula tell us that a huge force can be produced with a small energy input since Energy divided by a Tiny Number (distance) = Large Force Thanks for watching and commenting. Consider subscribing for more.
It's possible to build a smaller electromagnet that can lift a lot of weight but it's not easy without metal cutting and welding equipment. The secret to making a powerful electromagnet is to use a horseshoe magnet type design or better still is an iron core and coil inside a metal pipe. These magnet designs concentrate the magnetic field at one end of the magnet. I'll see if I can come up with a design to post but it will take awhile. I'm glad you find this topic so interesting.
I am looking to build an electromagnet that would work well picking loose odds and ends up in the gravel or out in the grass. I work on anything with an engine and am dropping and misplacing screws bolts and what not. any suggestions?
Easier to use a permanent magnet pickup unit like the magnetic floor sweepers found at the following link: www.northerntool.com/shop/tools/product_200400169_200400169?cm_mmc=Google-pla&Google_PLA&Construction%20%3E%20Road%20Magnets&A.M.K.%20Magnetics&gclid=Cj0KEQjwg8i_BRCT9dHt5ZSGi90BEiQAItdjpLj4tcJvitkTsNd8G9vKWpz5iVYzsQ4FikaS65KnebQaAji_8P8HAQ They are not all this expensive. Thanks for watching and commenting.
Your coil resistance seems too high for a microwave oven transformer. The resistance of the coil should be about 0.5 ohms. Are you using the coil with a few turns or many turns? If you've made your own coil it should be made of about 100 turns of # 18 to #16 wire. You can always use a larger voltage to increase the pull.
Now apply this to a free energy magnetic motor that can power its own electric charge. ( self propelled super charged magnetic electric engine) shit you make a wheel that has its own magnets copper wires and self charged battery incased in a wheel hub with a electric motor. You got a wheel that doesnt need an engine. Thats a patent within itself. Who need a heavy engine when the wheels can do all the moving?
Wow that's incredible. I can't believe such a tiny battery can generate that much force. Now, i got a question. If you polarize the battery the other way, generating that the coil actually repells the handle, will it be able to put it off? will it push the handle out to the ground? or will it start oscilating? and what about putting extra weight to the handle? because as the handle starts being repelled as soon as the circuit is connected the distance between the handle and the coil will increase, increasing the air in it, lowering the magnetic flux and the electromagnetical force, so that the handle might "stabilize" in some point.
Monox Val The magnetic field generated by the circuit induces the attractive magnetic force to hold the plate in place. If you reverse the terminals of the voltage source, you will induce a magnetic field in the other direction, which will still induce an equal but opposite magnetic attraction to the plate, binding them together nonetheless. Magnetic fields will only repel against other magnetic fields. In this electromagnet, there is one circuit, and therefore one magnetic field. That said,if you had a permanent magnet you could notice the changing field.
You are better off using the higher turn coil side for those small batteries. You will still get a strong magnet and current draw will be reduced. The fatter coiled primary side works best with low impedance sources that can supply the current like car battery.
+EETechs Not really. The impedance of the primary coil is best since its resistance more closely matches the internal resistance of the battery. This creates a better energy transfer from battery to coil.
+Dorian McIntire I'd be willing bet you :). The amp turns are what matter. You can achieve the same magnetic force with many turns of smaller wire and less current draw versus using the bigger coil that will draw more current. Also magnetic field strength is not a function of the maximum power transfer theorem. It is current and amp turns that determine the magnetic field strength up to within reason of course if we are not into the saturation region of the iron. Try this: get a variable current source and set current to value such that it's enough to hold some mass X for the primary side. Record voltage applied by the current source needed to produce the current the source is set at. Then do the same for secondary side. What you will find is that you will need more batteries for the high voltage side, but the current will be less so the batteries will last longer. The other side will used more current at less voltage, but the batteries will die faster.
+EETechs I'm very familiar with the concept of ampere-turns, but you neglected to take into account a critical element.... winding resistance. The primary has a winding resistance of 0.5 ohms with 100 turns of large diameter wire, the secondary has a winding resistance of 60 ohms for 1000 turns of small diameter wire. Current for the primary is 1.5V/0.5 Ohms = 3 amps, current for the secondary is 1.5V/60 Ohms = .025 amps. For the primary we have 3A x 100 turns = 300 AT while the secondary has 0.025A x 1000 turns = 25AT. I verified this through experimentation long ago but I just wanted to explain why the secondary is not a good choice. In this case Max Power transfer does bode well with the particular voltage I choose and it does not stress out the winding thermally.
Dorian McIntire You don't use 1.5 volts for that side. You use higher voltage for the high voltage side. So more AA batteries, but less current draw. If it's 1000 turns and you need 300 AT then that is 0.3 Amps. The voltage will be 18 volts if the resistance is 60 ohms. That is 12, 1.5 volt batteries. It will last 10 times longer than your set up of 1.5 volts applied to the .5 ohm winding. Now do you get what I am saying?
+EETechs I understand what you are saying but 12 - 1.5 volt batteries in parallel will allow the unit to work 12 times longer. The point of using the 1.5 volt battery in the video was to show that a small, taken for granted, power source can produce a tremendous magnetic force. I just wanted to point out that with any electromagnet design there are complicating factors when trying to produce the best scheme for such an electromagnet. The power dissipation using 18 volts @ 0.3 amps on the secondary coil is 5.4 watts while the power dissipation using 1.5 volts @ 3 amps on the primary coil is 4.5 watts. Can we agree on this? Thanks.
Great Video ! I was looking to make an electromagnetic to pick up waste metal from a (cooled) bonfire, so rushed out to find a microwave and did what you said and got excited ! Didn't get the results I saw on the video and then discovered it only works with 120V transformers - I am from the UK with 240V - is there any way I can over come this - Thanks
leachim2 Using twice the voltage would help but I would move up to 12 volts to get better results. Once pieces of magnetic metal are attracted to the magnet they will begin to short out the magnetic flux so you should pull this material off the magnet frequently to keep the field strong.
Wow its amazing to see how much potential one little AA battery has when hooked to such a large coil! All that energy being held in the magnetic field through the ferrite. Do you have any idea how many windings and what gauge the coil is? I'm really interested to know, does applying the lifting force cause a change in the current drawn from the battery? Hook it up the amp meter and lift; for science!
+Zak M-O The metal in a transformer is typically silicon steel and has a very high permeability. This means the magnetic field strength is very high inside the steel and has a high holding strength if the magnetic field is locked inside the metal. The gauge of the copper is #16 to #18 wire with about 100 turns. I will measure the current to see if the current does increase during lifting. Thanks for commenting.
Dorian, I need to make a very strong electromagnet in order to pick up nails, wire, etc along an old fence line I have removed. I see how you've made this, but wonder whether you could apply it in a manner in which I could have one, or several attached to a 6-8' long piece of metal and drag it behind a tractor, thereby picking up the pieces from the ground. Many pieces would be partially buried in dirt, grass, etc. I can design a cart, tines to stir up the dirt, etc. but am uncertain on how many of your magnets, or application to a piece of steel, would be required. Also, would more power increase the strength and field of the magnet? The small magnets on rollers to pick up debris won't work in a pasture. I need something with power.
Several of these connected in parallel may do the job but you should put a plastic shield over the magnets to keep debris from getting inside the electromagnet. Increasing the voltage would make the magnet more powerful. Good luck.
What do you mean no? Change the flow of current by changing the where wires end on battery and instead of getting attraction you will get repulsion from electromagnet
no you won't. if you flip it around, then the current will still whiz around and create magnetic force, the only thing is, that force would be a South Pole instead of a North Pole, or vise versa. you could, however, make it repel from a GIANT magnet on the floor of the same polarity of the electromagnet. Listen to Hot Sausage. (above)
Not sure I understand why only thick metal can be lifted. Pretty unfamiliar with the whole electromagnet field. What type of magnet would work to lift and or bend thinner metal so as to possibly pull a small dent out of sheet metal?
Thick metal object offer low resistance to the magnetic field so many field lines can dive into that material. Each field line helps hold the magnet against the thing you are lifting. You can create an extremely powerful magnetic field, for a brief period of time, by pulsing a huge electric current through an electromagnet briefly. For example you could use the electromagnet in the video in conjunction with a charged capacitor that is charged to a voltage much higher than 12 volts. This might be able to remove a dent.
Dorian: Thank you much for your video. My lil son and I recently made our 1st electromagnet, and I'm pretty sure we'll be doing yours next. :>) One question though: about how "long" (whatever that may mean;>) does a typical AA last?
you good, you got me for a second but it took me 3 minute to find out your trick, the green wire connects to - side of battery no problem, but the yellow wire is cut in half, the first half (one side connected to electromagnet and the end goes out of screen and you connected to +line dc power supply "probably +24v dc" ) the second half you connected to the other -line power supply -24dc and comes into the screen and you connect it to + side of 1.5v AA battery {basically the battery it just middle of the power supply} you know why i say that. it because 1.5v never ever makes such big spark . that spark shows there is a power supply with at least 2 AMP power some where.. ) at 1.04 when you connect the battery makes that spark and on 2.25 makes that spark the yellow wire is out of the screen... and on 1.24 when you lift it the yellow wire is out of screen, and when you disconnect the battery 2.26 your video flashes means has been edited there.. you show a yellow wire complete to distract people.! nice job ... it need a lot of attention to get what you exactly done. that coil never activate to a magnate on 1.5v. and of course at end of the video you taped the yellow wire so it does not come to the screen . when it fail it pulls the yellow wire but it does not move forward with battery ...!!! of cource it because is connected to a power supply there !
The 1.5 volt battery (look up the specification for a AA battery) provides more than 2 amps to the coil which has a a resistance less than 1/2 an ohm. Have you ever heard of back EMF? when you disconnect a high current, flowing in a coil with a large inductance, a large amount of back-EMF is generated and it can create a large spark (notice the spark only occurs when I remove the battery). Instead of being a armchair skeptic try using the scientific method and build one for yourself.
Hello Sir, great video - very inspiring to me. Makes me want to learn more about electromagnets. Does the holding power increase with an increase in power? Thanks in advance.
Tell what I am doing wrong. So i decided to use a small 12volt motorcycle battery to make a simple electromagnet. I tool a piece of 1/2inch metal rod and wrapped a 12 gauge insulated stranded wire around the rod a bunch of times. The wire keeps melting and catching almost on fire?. is the battery to big??
The battery is supplying too much current because the 12 gauge wire has such a tiny resistance Try one of the following: Use many turns of a larger gauge wire (smaller wire) like 16 or 18 gauge but it should really be enameled wire (sometimes called magnet wire) because magnets tend to get warm and the insulation on rubber or plastic insulated wire takes up a lot of space. Insert resistor in series with the magnet coil to limit the current. You can make a high power resistor using a steel spring if the coils don't touch each other, Use a battery with less voltage like a 1.5 volt D cell battery. Hope this helps. Let me know how things work.
It looks as if you would need over 500 ft of 12 gauge wire to limit the current of the magnet to a value that wouldn't overload the wire and overheat the magnet. The current with 100 ft of 12 gauge wire hooked to a 12 volt battery is around 8 amps and the current with 500 ft of wire is around 16 amps. This information is according to an online wire gauge table I used. The resistance of 12 gauge wire is about 1.58 ohms per 1000 ft. The power generated by the magnet coil, in the form of heat, is around 100 watts if 1000 ft of 12 gauge wire is used. You can only operate the magnet for a very short period of time with these lengths of wire since the buildup of heat is very quick. I'm working on a follow-up video to explain some of these issues about electromagnets.
No. Although the secondary winding has more turns its resistance is too high to allow a large current to flow. A good electromagnet is balance between coil turns and current. More turns means more resistance which means less current for a given voltage. I wanted to use a low voltage for this particular electromagnet.
im using the primary coil straight from a microwave so not sure why it doesnt have a resistance of 0.5 ohms i will get another coil and see if it has lower resistance
Are there any dangers as far as the battery failing or heat buildup that we should watch for in particular? This is great. Also, I find it odd that as much force that is being generated, when you left the "handle plate" off of the lower piece and applied power, it didn't really POP into place. I would think that this could create a potentially dangerous magnet that might pull nearby metal objects toward it rapidly when the voltage was applied. No? It didn't look like it in the video. Is this a function of the power decreasing exponentially as distance increases?
Use a low voltage for lowest amount of heat generated and longest battery life. Most magnets like this one have a very short range but can be very powerful at these short ranges. You are right that the forces fall off exponentially as the distance is increased. Thanks for commenting.
Ryan Metcalfe You really need a coil without a core to sense metal long distances. Proximity sensors, for instance, use small iron cores to sense very close metal objects on the proper end of the sensor.
Dorian McIntire Im a very very beginner in electromagnetism... Actually am a software developer.. But loves electromagnetism very badly.. So you mean the core for stronger magnet and without core it can attract from far or with out core increases the magnetic fields surrounds it?
Is there a way to modify this to function like a bitter magnet? Would welding a hollow iron pipe to it work, or would that just make the magnet taller?
awesome video!! i read a comment down below about pulling out nails. what do you think would be the smallest size of an area that you can apply tons of pressure?
lester alvarez It's very hard to say. Magnetic pull decreases quickly with (1)-distance from the target and (2)-small contact area with the target. Take a look at the following video to see how much can be lifted with an electromagnet like the one in this video. th-cam.com/video/cpSHTvzoZII/w-d-xo.html&feature=gp-n-o&google_comment_id=z121ex1xqrecf1am223cf5cgwpfdsbfbg04 Thanks for watching and commenting.
+sgman73 Thick wire is good. You should be using the coil with larger size wire and fewer turns? Check the continuity on the coil with an Multimeter to make sure the wire is not open-circuited. Of course make sure the battery is good also.
This magnet design acts much like a horseshoe magnet and concentrates the magnetic field near the tip. To project the field outward futher (but weaker) you will probably want to use a more conventional electromagnet using a straight iron bar with a large coil wound around it. This should allow the field to reach out futher for smaller objects but with less force.
To make a strong electromagnet you need to keep the following in mind:
-Make the core out of a high permeability material such as iron. The iron wire in a coat hanger works well.
-Use many iron wires side by side to increase the area of the core.
-Use many turns of large diameter copper wire in the coil.
-Make the core into a U-shape so that the north and south poles are very close together
I can create a video demonstrating these techniques if it will help.
Thanks for your interest..
Hello Dorian.
Could you please send me a video for the electromagnet core made by hungers , I would like to try it,
If you don't have the video please send me the diagram or scetch or even explanation how to do it.
My email
nafim712@gmail.com
I really appreciate that
It is amazing how many uses a microwave transformer can have.
That's exactly why I bought one!
AA battery when gets connected to MWT primary winding draws 2.6 Amps x 1.5 Volt = 3.9 Watts of power is used.
Guy's, do you see what's going on here? This is a over efficient machine. You turn this electro magnet into a some kind of pulse DC Motor and you are going to get much more power than 3.9 watts! Dorian, you did a great job man, thanks for making this video.
You cannot get more energy than 3.9 Watts.
Vic, the science is all about making improvements on technology that uses less energy and does more work 4 U. Lets take a look at the recent advancement in light technology for example: (equiv. 60 watts) it takes 10 watt Led = to Incandescent 60 watt. Light bulb projected lifespan: Led 50,000 hours, Incandescent 1,200 hours. If you care to learn more? Please use these key words: LED Light Bulbs: Comparison Charts.
Be careful. Holding two objects together does not require energy - it only requires force. If I duct-tape two object together the duct tape is not providing energy to allow this to happen it is providing a force. Energy is involved when a force acts over a distance. The electromagnet must be in very close contact to the object it lifts, it can only pull the object upward when the objects are essentially touching - so very little energy is involved. The energy required to lift 50 lbs (22Kg) 0.1 mm high is only about 0.02 joules - which is not much.
in youtube we obey the laws of thermodynamics >:U
Yes we do, although many TH-cam videos would have you believe their is no such law. ;-)
man that's a good demonstration ! i would have never thought a small battery that size would be able to generate that much force!!!
Electromagnets can create very large magnetic fields and forces when objects are very close together. Unfortunately the AA battery must supply about 2 amps of current and will not last for long.
When you say "it will overheat in a few minutes" can you elaborate on that? What will over heat? The battery or the magnet? What happens if the electro magnet overheats?
really love the background night cockroaches sound. cool magnet too
I connected a car jump starter to my electromagnet and the results were much better. Thanks for you help
i never thought i can build a home made strong magnet until i saw this video. so simple and straight forward! INSPIRING! thank you for the upload. keep it up.
You're welcome. Please send us a link to your magnet after you build it. Thanks for commenting.
In general this is true. A large core area allows more magnetic flux to be conducted to the object to be lifted.
Thank you!!!!!!!!!!!!!!!!
I was looking for something like that but so hard to find...
Hi Javed,
If the oven works the transformer is obviously good.
If the oven does not work the chances are that the magnetron is bad but the transformer is fine. I have not found a bad microwave oven yet with a bad transformer.
Checking the coil in the oven will require you to gain access to the transformer, removing one of it's connectors and checking the resistance of the primary coil (fewest turns). My coil has a resistance of 0.5 ohms.
Hope this helps. Feel free to ask other questions.
Thanks Dorian. You helped me a lot. I study and research calculation and I found out that Gauge 16 is the most efficient. It has very low resistance so I can make lot of turns as compared to smaller wires. Thanks again for wonderful video.
That is incredible! What I wonder how destructive the inductance would be if turned off and on with a transistor.
That's why you use a flyback diode, though burning transistors would be fun.
Cool thanks! it gives me an idea to make electromagnets for some Halloween props. Wouldn't want to use Relay's to turn the magnets on because they are usually noisy so wondered about using a switching transistor. I will have to look at a flyback diode to see if that would protect the transistor.
If you decide to use a relay, keep in mind you need a flyback diode across the coil too.
Potentially well over 10 times the input voltage. Is this not the principal of tazer or ignkypr coil in an engine ?
Stephen,
Make sure you use a fresh battery capable of providing the large currents required by the electromagnet. A 9 volt battery will not provide enough current to do the job even though it has a higher voltage than a AA or C cell. 9 volt batteries are designed to provide higher voltages not currents. You will need a small motorcycle battery or car battery if you really need more power. Also make sure you use heavy wires to conduct current from the battery to the magnet.
so if you were to flip the terminals or flip the polarity would you get the piece of metal to jump up???
+Alan Gonzalez No, magnets lifting iron is only attractive. Magnets lifting magnets is another story.
Its not important that the coil touch the metal.
Be careful not to remove the insulation on the wire. The wire is coated with a thin transparent coating that keeps the copper in the wire from shorting together.
This is an amazing video. I never thought about transformers in that way but after watching this video, it was like a light bulb went off and I said, "duhh". lol When I saw this I immediately went to my basement and tore apart one of the microwave transformers I had and built that electromagnet in 30 mins. It is soooooooo simple its awesome. Videos like this inspire others.
Great! I'm very happy that you found the video inspiring and particularly impressed you built the electromagnet so quickly. Thanks for sharing and commenting and have fun showing it off.
If you left it attached to the battery how long before it dies?
I want this question answerd too!
@@joshuanorris9785 still waiting for the answer though
Measure your current.
Divide battery Ah rating by current.
Result is battery life in hours.
The reason you get a heavy spark when you disconnect is this. When you connect the power, you get that very strong field built up around the core and coil.This very strong field is what lets you pick up very heavy items. When the circuit is opened, all that magnetic field that was built up around the coil and core suddenly collapses right back into the coil that made the field, to begin with. This is 'back voltage. It is EXACTLY why a condenser was placed across the points in gas engine ignition systems, be it a battery and coil or, a magneto. The condenser absorbs the back voltage and keeps the points from burning up.
Stephen,
Did you use a microwave transformer for the core? The trick to lifting heavy objects is to make sure the objects you're lifting are very close to the electromagnetic.
Magnetic fields do not travel well through air because the permeability of air is very small compared to the permeability of iron and other magnetic materials.
Even large junkyard electromagnetics have to almost touch the material they are lifting but they can lift very heavy objects if they are in contact.
Good luck
No, This electromagnet is much like a junkyard magnet. It can pick up large loads in good contact with the magnet. Read the companion information for details.
A rod-shaped electromagnet will pick up objects further away but with less force.
From 1,5v thats amazing, I would never have thought that much force could be available....12v/9ah battery would give how much force then ?..Lift a car almost. How can you protect the battery from over heating, because this circuit is basically a short circuit.?....Nice video, I subscribed to your channel.
Higher voltages should only be used for short periods of time to keep both the electromagnet and the battery from overheating especially when using higher voltages. You are right that the coil is essentially a short circuit, or at least a very low resistance (about 0.5 ohms), so things can get hot quickly if the current is sustained. Thanks for commenting and subscribing.
Dorian McIntire
Thanks for your reply....In your experience is there an optimum coil size for say 12v/2amps supply continuous..without everything getting hot.
MrFreddiew1 The interactions between coil turns, coil wire gauge, resistance, power dissipation, current, voltage and power supply capability are pretty complex so I'm not aware of any formula for optimum efficiency. The simple rule of thumb is to use the smallest gauge (largest diameter) wire you can find, use as many wire turns as you can and pass as many amps through the wire as you can without overheating your power supply or magnet.
Dorian McIntire
Trial and error.....Ok thanks for your response.appreciated.
Looking at only direct current in a coil, all copper coil will have some DC resistance. Current is i=v(voltage)/r(resistance) , Power is watts = i * v. Given that i = v/r, watts is also expressed as w=v*v/r or w=v^2/r . The resistance will change a little as it warms up, but for the most part and for simplicity we might assume the resistance doesn't change. putting that together means that as voltage grows, amps will grow geometrically to the voltage, and power consumed grows exponentially to the voltage. After the magnetic field is established, all the power being consumed is dissipated as waste heat from the resistance in the copper wire. This slowly heats the iron core. so run times is limited by higher voltage and how fast the core can dissipate the heat. Now without an iron core, a coil's magnetic field strength has a linear relationship to the the amount of current flowing through the coil. A coil with an iron core will have a stronger magnetic field as the magnetic domains in the metal align and contribute their magnetic fields. But it has only so many magnetic domains, and at some point their are no more domains to align and contribute to the magnetic field. this is called saturation. and adding additional current to increase the magnetic field takes a bend growing at a slower rate.
Now on optimization. If we restrain our discussion to current below magnetic saturated core, and look at the geometric growth of current to voltage and exponential growth of power consumed to voltage, and ask for an optimum ratio of (magnetic field strength/power consumed) then we might look at lower and lower currents as having better ratio. But at almost 0 current, one would not have a useful magnetic field. In other words, one should probably start with asking what kind of magnetic field does he want, and how to optimally achieve that given a specific application's constraints.
Now if you must use 12v you might try pulse with modulation and vary the duty cycle to control how much power is fed into your coils. you may also consider ways to active and or passively cool the coils.
One might also try voltage divider. by adding a resistor in series first measure the ohms across a coil. This might take a bit to settle down to one value. if the max current you want is 2 amps. Then the equation is 12 volts /( resistor + coil resistance) = 2 amps, and solve for resistor.
Hi there, thanks for your great video! Very helpful. I was hoping you could tell me how long that AA battery will last whilst in use.
Thanks very much, Jo
Probably only about 5 minutes for an "AA" battery but this really depends on how much of a rest you give the battery between uses. A "D" Cell battery will last much longer, maybe around an hour. The electromagnet uses about 1.5 amps at 1.5 volts since it has a coil resistance of about 0.5 ohms.
The specifications for a typical battery can be found on Eveready's website. Just Google "eveready technical information" and you will find technical information on all their batteries with charts and graphs about useful life and current capabilities.
I use the AA battery for effect since it surprises most people that such a small battery can create such a large force.
The key to this effect is that the force does not extent far beyond the magnet.
Thanks for commenting.
The wire coil will overheat due to the large currents in the coil when connected to higher voltages. If the coil gets too hot the wire insulation can burn and short circuit the electromagnet.
You just have to make sure you let the coil cool before using the electromagnet again.
Good, glad you're having better results. Have fun.
+Oliver Smithdeal Make sure the microwave oven has been unplugged for while before removing transformer. No other problems as long as you don't go overboard on the battery voltage or leave it connected too long.
+maxxlexx1 it wouldn't be a true perpetual motion engine simply because the amount of energy required to power the motor would be less than that generated by the wheel. With that said, as long as the magnet had power you could turn a wheel, if set up correctly.
The wheel could charge that lil 12v battery and it could intermittently fire it off to keep it going but it still wouldn't be considered perpetual motion simply because of the way individuals define it... something out there could literally run for the rest of a individuals life and still not be considered perpetual motion (wear is sited as one of the reasons). lol
From a microwave oven transformer. Every microwave oven has a core like this used to create the high voltage needed by the magnetron and you can break the core apart using a hacksaw or grinder. I've found lots of uses for these transformers including welders.
Isn't this how electromagnetic security doors work? So there obviously is a safe and efficient way to keep it powered for an extended period of time, otherwise it wouldn't make a very good lock. You could just wait for it to fail and open the door. Also, what other appliance can be used in place of a microwave. Thanks!
Yes most electromagnet door locks work on the same principle. It is very easy to produce very high pulling forces when object are in contact. While any modified transformer will work I have found the microwave oven transformer to be the easiest to use and because of its physical size the pulling forces can be extremely high.
No, a coil alone will produce a relatively weak magnetic field for a given current. To concentrate the magnetic field you need a material with a high permeability like iron.
The secondary has 10 times more turns of wire but 100 times more resistance.
Since the strength of the field is proportional to the ampere-turns (current x number of turns) you will get a stronger magnetic field for a given current. To get the same current as the secondary you need 100 times the voltage but your magnetic field will be 10 times stronger since it has 10 times more turns than the secondary.
Bottom line is that you will need 10 times more voltage to get the same effect.
Higher current is necessary to increase the strength and this requires a higher voltage.
You must make sure your power supply can create the current necessary because some power supplies can provide the voltage but not the current.
Too much current will cause the magnet to get hot so be careful not to burn the unit out.
Hi, thank you so much for giving back to the community by sharing your knowledge! It is an awesome video! I have a question about those electromagnetic displays that are sold on amazon and other sites online. I bought one and I opened the floating object and took out the magnet so i can float something else in it but my object is too heavy. How can I increase the weight it can hold?? I would really appreciate if someone could help me figure this out :) thank you so much
a couple of weeks ago I brought home a microwave from the transfer station ,I did know i could use it for a welder or spot welder but I really got it for the electronics . So came across this vid , I was wondering what kind of application can I use this project for. I was trying to find a magnetic door lock . This would be too large for that application. Dorian I always enjoy watching your Very informative Vids.Thanks.
Thank you Vic. I really appreciate your comment.
Thank you for your efforts and sharing this video.
bhavani the core is straight out of the transformer with no modification. Use the winding with largest wire only. Remove the winding with fine wire. Make sure the transformer is a 120 volt transformer and not a 240 volt transformer.
what does the one with fine wire do?
It is the high voltage winding (2000 volts). The other winding (one to use) is the primary winding (120 volts).
Cool. You said that the transformer gets hot if you leave the current on long enough. Does it get hot enough to melt? Also, if I were to use a 12 volt battery, would it be strong enough to lift 30 lbs from 8 inches away or does the electromagnet have to be pretty close or make contact in order to make the lift? Thanks a bunch and sorry if my questions are any inconvenience.
+AGENT G It will lift hundreds of pounds using a 12 volt batter for a short period of time. Distance is a problem for magnets if you want them to create strong forces. Much depends on the thickness and type of iron and how close it is to the magnet.
Thanks. I appreciate it. I also appreciate your educational videos. Thanks for sharing with us.
Excellent and simple. Can this be adapted where the transformer core is mounted to an iron bar or pipe so it can be used to clean an area of iron like picking up nails in the yard? Also how long might the battery last? Any advanatge to using a higher voltage battery or power source?
A mere AA battery can lift 50 lbs against gravity.
Isn't it overunity?
Isn't it free energy?
Not really since it cannot do it for long. A few of concepts I wanted to demonstrate was the difference between energy and power and how magnetic fields can be very intense over very small distances.
dude my mouth has been stuck open and my eyeballs are pippin out of my head in amazement and excitement. WOW dude what in the world... THIS IS SO AWESOME. Sir, can this me used as a clamping device to glue wood parts together. What is the maximum opening allowed before clamping force starts to fall off? thank you sir for sharing this Im gonna make it tonight..
STIZEN9 use the electeomagnet near the hinge and make the clamper adjustable (with a screw for example), this way you maintain contact between the magnet and the iron (giving you the force) without having the two camper hands in contact.
an interesting fact is that the video cuts as soon as you put the handle/plate back on and that your using 1.2 - 1.7 volts (depending brand and type of battery) to lift 50 pounds plus the bottom plate.
I'm sot sure if your comment is meant to expose some suspicion about the authenticity of the video claims or point out that this indeed works well. The video cut occurred because it took several attempts to keep the weights from shifting on the board while I was demonstrating the electromagnet. I put this video together on a whim and couldn't think of a easy way to immobilize the weights on the board. I didn't want to extend the length of the video by several minute while I was finally able to balanced the weights perfectly on the board so I removed the failed attempts.
BTW: The whole assembly was mounted on a board so students could step on the board while pulling up on the metal plate. Even large, male students could not break the metal plate away from the magnet with a fresh battery and a solid electrical connection so my claims are actually a downgraded version of an ideal situation.
Many viewer have built the electromagnet. I would appreciate it if these viewer would report their own results. Thanks.
no, the one you pulled out intact is the primary. the secondary is the output, or the 2KV.
Incorrect. If you want to power the electro-magnet from a low voltage source the resistance of the secondary is much too high.
so you are saying it is correct. The thick wire is the Primary. the thin wire is the Secondary. but who cares?
Man, that was REALLY something. Thanks a lot for sharing it :)
You're welcome. Thanks for commenting.
Thanks we have a microwave at work that's no working I want to do this
This is great, with lots of great answers already provided below. Many thanks.
I already used a MOT to create an electromagnet thanks in part to your video, but I'd like to teach some kids about eddy magnets as well, since they're learning about recycling centers and how they separate things. Is there an easy way to step-down an AC connection so it isn't quite as loud and reduces the risk of tripping a breaker. (I'll still run it through a power strip to avoid tripping breakers at the school.) Thanks again.
If you have two MOTs you can connect them in series but put the iron bar on one of the MOTs to make it act like a variable inductor. You should have the capability of drastically reducing the current and this is adjustable by moving the position of the metal bar on the current-limiting MOT. This is probably the best way to control the current without using a transformer or large power resistor. Have fun.
I have two MOTs, I understand "connect them in series," and then I got lost. I'm thinking that is probably a sign that I shouldn't mess around setting this up on AC, and I should stick with the battery for safety's sake. Thanks again!
Dorian,
Thanks for the quick response! In fact, yes, I did use a microwave transformer for the core. But I don't want to lift heavy objects. I actually want to lift very light weight objects (think nails, bolts, etc) but at a distance of about 6 inches. It's for an architectural model/installation.
Awesome video! I want one of these now. >:)
Two questions though.
1. Assuming the AA battery is fully charged, how long the charge last, would having a battery pack of some sort (4 AA battery pack or similar that you would find in a TV Remote) make it last longer?
2. Would it be safe to have on of these mounted on a wearable back plate to hold a sword (disconnect the battery, sword comes off, connect battery, sword won't come off at all) or would I be better off making something smaller/weaker?
Thanks in advance. :)
+umm36 The average capacity of a AA battery is about 1 amp hour, and the short circuit output (worst case scenario) is said to be between 1 and 5 amps. Now, that's pretty vague, but it should give you an idea. If the magnet draws 1 amp, you'll get one hour. If it draws 5 amps, 12 minutes. Chances are it'll be closer to the 1 amp, since small batteries get kind of hot putting out 5, but I honestly can't say, I'm just speculating.
As for the second question, I might be able to shed some light on a safety issue. As far as the magnetic field goes, you'll be fine, unless you have metal rib/back/hip implants, or a doctor left a scalpel in you. The sword however, may give you trouble. Since the entire magnet is oval in shape, and the sword is not a full square, it'll likely try and align itself with the magnet. If you take the sword off and the magnet activates unintentionally, you won't know until you try to put the sword back on, and the magnet will suck the sword towards itself. Once it's captured by the magnet, the force will overwhelm your arm, and you'll lose control of the sword. If the magnet twists the sword the wrong way, it could slice into you or someone around you. It's giving the sword at least 200 newtons, which, given a 1 KG sword, can bring the tip to (roughly) 350 km/h, and that's very conservative. So, if you're going to use a sword, make sure to have it on the electromagnet before turning it on. Maybe use a resistor to prevent the magnet from producing that much power.
Awesome, thanks.
So a single AA battery would power that for around an hour if set up right?
umm36 I can't promise that. It could be as little as 20 minutes or as long as an hour, maybe longer. To add to that, if the battery is being drained at a high rate, it could overheat, causing damage and reducing it's life. A resistor might help, since it won't let the current flow at short circuit rates, but it'll also bleed off some power.
The current drain from a 1.5v battery is a little over 1 amp so a AA will not last very long.
I use a AA simply for effect so students can see how a small power supply can do fairly impressive things.
If you want the battery to last longer use a D cell. You should get about 30 minutes from a AA and 8 hours from a D according to technical information from Eveready's web site.
A 12 volt battery will allow the electromagnet to lift over 300 lbs but it will overheat in a few minutes.
Have fun.
But what if you connected a 5.00 v to 1.2A AC ADAPTER on this
The higher the voltage the stronger the magnet
The AC, and regarding an item, would pick it up, drop it, pick it up drop it, pick it up sixty times a second, so you'd never get anything lifted. If, on the other hand, you were using a AC to DC converter, you'd be off an running.
If you use the secondary wire to supply a current to make a strong electromagnet, could you then take the primary wire to make it into a speaker? A speaker can be made by just using a copper coil and a really strong magnet (and, of course, a cone of some sort), so I don't see a reason (in theory) why this couldn't be used to make an Electromagnetic Speaker.
i have not microwave oven transformer but other same transformer wind 22 gauge wire 50 turns but not work supply 240 volt AC
how i make electromagnet ?
this electromagnet repeals the aluminium for eddy current create because i will use in making flying board
Karansinh Doliya use a step down transformer for 220VAC to 24V AC you can get more powerful magnet 🧲 increase the winding
Built one of these myself. Works great!!! Thanks
narcat Thanks for sharing this with the group. I've had a few comments from non-building, critics who believed the video was doctored. I love it when others chime in to put this non-sense to rest.
I really appreciate your comment.
What would happen if you added a second primary wire round from a second microwave? And obviously applied a current to that one as well.
thanks my friend you gave me a brilliant knowledge about electro magnet
That'd make an awesome motor
?!?!?!?!?!? it would make a terrible motor!!!1
Ronald RC Brushless motors work by using electromagnetic force to pull a rotor towards each next magnet and then switch polarity and push themselves away from said magnet in a rapid transition. The more powerful and power efficient the electromagnets are, the more powerful the motor is. If you could position some of these along a rotor with some hall sensors and circuitry to control the polarity, thats possibly roughly 50lbs of force per magnet on the rotor, and if you could power it with a few small cells, holy torque. This would make an AMAZING motor
YSC That was my first thought, someone with better resources than you or I have, needs to collect like 6 of these and make a massive brushless torque monster
I'm stunned that you got that much force from so little current.
The electromagnetic has about 300 Ampere-Turns (100 turns * 3 amps) of MMF. This creates a very large magnetic flux when the reluctance (resistance to magnetic flux) is very low.
With the electromagnetic, as long as the air gap is very small the magnetic field strength is very large. The magnet does not need much power to provide a large pull since it is not actually moving the weight relative to the magnet if the weight is in contact with the magnet.
Any time you want to create an electromagnet with a lot of pull you need to minimize the air gap between the object you want to pull and the magnet.
BTW: This electromagnetic will lift well over 100 lbs with a 12 volt power supply.
Thanks for commenting.
Two quick questions, and thanks for the response. I'm in the process of copying your hack for practical use in the field.
1. Should I/can I trim down the leftover core material so that it's level with the winding to reduce weight?
2. Looks like the primary winding is used. Is that the case?
Aaron Baca
Yes you can trim down the core but make sure the cut is very straight and doesn't produce any air gaps when the core contacts an object or you will seriously reduce the lifting power of the magnet.
The primary winding is the one you want to keep. This is the winding with the largest diameter wire.
This has some practical applications, make me a pair of space boots. Thanks
You're welcome. I'll make you a deal, if you go to space I'll make the boots ;)
Is it safe to go into a microwave oven ( broken down ) and remove the transformer WHAT ARE THE PRECAUTIONS I NEED TO KNOW this is interesting I LIKE THIS TOY
Yes it is safe as long as the oven is not plugged in. There are now other videos available on TH-cam that demonstrate the details of modifying the transformer.
Really cool video :) Can I make a video request? Can you make a video for 1) the optimal characteristics to optimize a 1.5v aa battery and 5v usb (@500mA or 1A) electromagnet?
2) A breadboard or electronic controller for pole switching one or more magnets?
Great video, thanks for sharing, a few questions;
how important is the metal base where the coil fits nicely?
Also how do you make the magnet to repel the other half of the transformer or any other metal?
Ernesto Del Bosque The metal base is very important since it helps keep the magnetic permeability (sort of like magnetic conductivity) high and keeps the magnet strong. A magnet that repels other metals is possible but such a magnet must use AC power to work. It will not repel iron but will repel aluminum and copper by inducing electric currents in these metals that will create a counter magnetic field. I will show such a device in a future video. Thanks for your comment.
Thanks a lot for your videos
Ernesto Del Bosque Thanks for watching.
Is there any chance the battery will explode? Or is there a risk of getting shock when taking apart the microwave without it being plugged in? Please answer ASAP
W=UIt, if electrical current last too long, it will explode.
Unbelievable that a small battery like that in combination with a transformer coil can produce that much magnetic energy!
Andre Poelman The key to this feat is that the magnet only has to produce a powerful force. Large forces can be produced with very little energy if the distances are small. Since Energy = Force x Distance and the object is already touching the magnet the magnet does not actually have to move the object. In this case the formula tell us that a huge force can be produced with a small energy input since Energy divided by a Tiny Number (distance) = Large Force
Thanks for watching and commenting. Consider subscribing for more.
I love the video can you make a smaller electromagnet and make it hold 50/100 pounds I need to know can you help me out thanks.
It's possible to build a smaller electromagnet that can lift a lot of weight but it's not easy without metal cutting and welding equipment.
The secret to making a powerful electromagnet is to use a horseshoe magnet type design or better still is an iron core and coil inside a metal pipe. These magnet designs concentrate the magnetic field at one end of the magnet.
I'll see if I can come up with a design to post but it will take awhile.
I'm glad you find this topic so interesting.
I am looking to build an electromagnet that would work well picking loose odds and ends up in the gravel or out in the grass. I work on anything with an engine and am dropping and misplacing screws bolts and what not. any suggestions?
Easier to use a permanent magnet pickup unit like the magnetic floor sweepers found at the following link:
www.northerntool.com/shop/tools/product_200400169_200400169?cm_mmc=Google-pla&Google_PLA&Construction%20%3E%20Road%20Magnets&A.M.K.%20Magnetics&gclid=Cj0KEQjwg8i_BRCT9dHt5ZSGi90BEiQAItdjpLj4tcJvitkTsNd8G9vKWpz5iVYzsQ4FikaS65KnebQaAji_8P8HAQ
They are not all this expensive.
Thanks for watching and commenting.
Your coil resistance seems too high for a microwave oven transformer. The resistance of the coil should be about 0.5 ohms.
Are you using the coil with a few turns or many turns?
If you've made your own coil it should be made of about 100 turns of # 18 to #16 wire.
You can always use a larger voltage to increase the pull.
Now apply this to a free energy magnetic motor that can power its own electric charge. ( self propelled super charged magnetic electric engine) shit you make a wheel that has its own magnets copper wires and self charged battery incased in a wheel hub with a electric motor. You got a wheel that doesnt need an engine. Thats a patent within itself. Who need a heavy engine when the wheels can do all the moving?
tesla need to do that
Hello friends! A very delight video. Bravo! Can i ask if yoy know how to make same results with 220volt microwave oven transformer? Thanks in advance!
+lowkickfighter You can get the same results but you will probably need more voltage to get the same strength.
Beautiful. Im going to make one connected to a switch
Good. Please deep us posted on how it goes and post any questions you might have.
Wow that's incredible. I can't believe such a tiny battery can generate that much force. Now, i got a question. If you polarize the battery the other way, generating that the coil actually repells the handle, will it be able to put it off? will it push the handle out to the ground? or will it start oscilating? and what about putting extra weight to the handle? because as the handle starts being repelled as soon as the circuit is connected the distance between the handle and the coil will increase, increasing the air in it, lowering the magnetic flux and the electromagnetical force, so that the handle might "stabilize" in some point.
Monox Val The magnetic field generated by the circuit induces the attractive magnetic force to hold the plate in place. If you reverse the terminals of the voltage source, you will induce a magnetic field in the other direction, which will still induce an equal but opposite magnetic attraction to the plate, binding them together nonetheless. Magnetic fields will only repel against other magnetic fields. In this electromagnet, there is one circuit, and therefore one magnetic field.
That said,if you had a permanent magnet you could notice the changing field.
I suppose you could try two primary coils in series, and double the input voltage to increase power.
Yes, or connect the two coils in parallel and use twice the current.
Enjoyed it Dorian. Thanks
You're welcome. Thanks for commenting and please share. Dorian.
You are better off using the higher turn coil side for those small batteries. You will still get a strong magnet and current draw will be reduced. The fatter coiled primary side works best with low impedance sources that can supply the current like car battery.
+EETechs Not really. The impedance of the primary coil is best since its resistance more closely matches the internal resistance of the battery. This creates a better energy transfer from battery to coil.
+Dorian McIntire I'd be willing bet you :). The amp turns are what matter. You can achieve the same magnetic force with many turns of smaller wire and less current draw versus using the bigger coil that will draw more current. Also magnetic field strength is not a function of the maximum power transfer theorem. It is current and amp turns that determine the magnetic field strength up to within reason of course if we are not into the saturation region of the iron.
Try this: get a variable current source and set current to value such that it's enough to hold some mass X for the primary side. Record voltage applied by the current source needed to produce the current the source is set at. Then do the same for secondary side. What you will find is that you will need more batteries for the high voltage side, but the current will be less so the batteries will last longer. The other side will used more current at less voltage, but the batteries will die faster.
+EETechs I'm very familiar with the concept of ampere-turns, but you neglected to take into account a critical element.... winding resistance. The primary has a winding resistance of 0.5 ohms with 100 turns of large diameter wire, the secondary has a winding resistance of 60 ohms for 1000 turns of small diameter wire.
Current for the primary is 1.5V/0.5 Ohms = 3 amps, current for the secondary is 1.5V/60 Ohms = .025 amps. For the primary we have 3A x 100 turns = 300 AT while the secondary has 0.025A x 1000 turns = 25AT.
I verified this through experimentation long ago but I just wanted to explain why the secondary is not a good choice. In this case Max Power transfer does bode well with the particular voltage I choose and it does not stress out the winding thermally.
Dorian McIntire You don't use 1.5 volts for that side. You use higher voltage for the high voltage side. So more AA batteries, but less current draw. If it's 1000 turns and you need 300 AT then that is 0.3 Amps. The voltage will be 18 volts if the resistance is 60 ohms. That is 12, 1.5 volt batteries. It will last 10 times longer than your set up of 1.5 volts applied to the .5 ohm winding. Now do you get what I am saying?
+EETechs I understand what you are saying but 12 - 1.5 volt batteries in parallel will allow the unit to work 12 times longer. The point of using the 1.5 volt battery in the video was to show that a small, taken for granted, power source can produce a tremendous magnetic force.
I just wanted to point out that with any electromagnet design there are complicating factors when trying to produce the best scheme for such an electromagnet. The power dissipation using 18 volts @ 0.3 amps on the secondary coil is 5.4 watts while the power dissipation using 1.5 volts @ 3 amps on the primary coil is 4.5 watts. Can we agree on this? Thanks.
Thanks, very helpuful. I am building a levitator circuit.
Great Video ! I was looking to make an electromagnetic to pick up waste metal from a (cooled) bonfire, so rushed out to find a microwave and did what you said and got excited !
Didn't get the results I saw on the video and then discovered it only works with 120V transformers - I am from the UK with 240V - is there any way I can over come this - Thanks
leachim2 Using twice the voltage would help but I would move up to 12 volts to get better results. Once pieces of magnetic metal are attracted to the magnet they will begin to short out the magnetic flux so you should pull this material off the magnet frequently to keep the field strong.
There's something to be learned here .
Fronzi Approved .
I agree. Thanks for sharing and commenting.
Dorian McIntire cool.
Wow its amazing to see how much potential one little AA battery has when hooked to such a large coil! All that energy being held in the magnetic field through the ferrite.
Do you have any idea how many windings and what gauge the coil is?
I'm really interested to know, does applying the lifting force cause a change in the current drawn from the battery? Hook it up the amp meter and lift; for science!
+Zak M-O The metal in a transformer is typically silicon steel and has a very high permeability. This means the magnetic field strength is very high inside the steel and has a high holding strength if the magnetic field is locked inside the metal.
The gauge of the copper is #16 to #18 wire with about 100 turns. I will measure the current to see if the current does increase during lifting.
Thanks for commenting.
Dorian, I need to make a very strong electromagnet in order to pick up nails, wire, etc along an old fence line I have removed. I see how you've made this, but wonder whether you could apply it in a manner in which I could have one, or several attached to a 6-8' long piece of metal and drag it behind a tractor, thereby picking up the pieces from the ground. Many pieces would be partially buried in dirt, grass, etc. I can design a cart, tines to stir up the dirt, etc. but am uncertain on how many of your magnets, or application to a piece of steel, would be required. Also, would more power increase the strength and field of the magnet? The small magnets on rollers to pick up debris won't work in a pasture. I need something with power.
Several of these connected in parallel may do the job but you should put a plastic shield over the magnets to keep debris from getting inside the electromagnet. Increasing the voltage would make the magnet more powerful. Good luck.
Do you can use that force to repel 50 lbs,and make ufo craft ?
No
What do you mean no? Change the flow of current by changing the where wires end on battery and instead of getting attraction you will get repulsion from electromagnet
no you won't. if you flip it around, then the current will still whiz around and create magnetic force, the only thing is, that force would be a South Pole instead of a North Pole, or vise versa. you could, however, make it repel from a GIANT magnet on the floor of the same polarity of the electromagnet. Listen to Hot Sausage. (above)
You make a confusion with permanent magnets. Here the piece of metal which is pulled is not a permanent magnet. That's mean has no poles.
^^^^^^^ IIRC all electromagnetic fields have certain polarity to them.
We need this technology in snowboard bindings
Are there any videos demonstrating how to deconstruct the microwave transmitter?
Not sure I understand why only thick metal can be lifted. Pretty unfamiliar with the whole electromagnet field. What type of magnet would work to lift and or bend thinner metal so as to possibly pull a small dent out of sheet metal?
Thick metal object offer low resistance to the magnetic field so many field lines can dive into that material. Each field line helps hold the magnet against the thing you are lifting.
You can create an extremely powerful magnetic field, for a brief period of time, by pulsing a huge electric current through an electromagnet briefly. For example you could use the electromagnet in the video in conjunction with a charged capacitor that is charged to a voltage much higher than 12 volts. This might be able to remove a dent.
you should make a zero point generator
Dorian: Thank you much for your video. My lil son and I recently made our 1st electromagnet, and I'm pretty sure we'll be doing yours next. :>)
One question though: about how "long" (whatever that may mean;>) does a typical AA last?
you good, you got me for a second but it took me 3 minute to find out your trick, the green wire connects to - side of battery no problem, but the yellow wire is cut in half, the first half (one side connected to electromagnet and the end goes out of screen and you connected to +line dc power supply "probably +24v dc" ) the second half you connected to the other -line power supply -24dc and comes into the screen and you connect it to + side of 1.5v AA battery {basically the battery it just middle of the power supply} you know why i say that. it because 1.5v never ever makes such big spark . that spark shows there is a power supply with at least 2 AMP power some where.. ) at 1.04 when you connect the battery makes that spark and on 2.25 makes that spark the yellow wire is out of the screen... and on 1.24 when you lift it the yellow wire is out of screen, and when you disconnect the battery 2.26 your video flashes means has been edited there.. you show a yellow wire complete to distract people.! nice job ... it need a lot of attention to get what you exactly done. that coil never activate to a magnate on 1.5v. and of course at end of the video you taped the yellow wire so it does not come to the screen . when it fail it pulls the yellow wire but it does not move forward with battery ...!!! of cource it because is connected to a power supply there !
The 1.5 volt battery (look up the specification for a AA battery) provides more than 2 amps to the coil which has a a resistance less than 1/2 an ohm. Have you ever heard of back EMF? when you disconnect a high current, flowing in a coil with a large inductance, a large amount of back-EMF is generated and it can create a large spark (notice the spark only occurs when I remove the battery). Instead of being a armchair skeptic try using the scientific method and build one for yourself.
shockingly cool
Hello Sir,
great video - very inspiring to me. Makes me want to learn more about electromagnets.
Does the holding power increase with an increase in power?
Thanks in advance.
Tell what I am doing wrong. So i decided to use a small 12volt motorcycle battery to make a simple electromagnet. I tool a piece of 1/2inch metal rod and wrapped a 12 gauge insulated stranded wire around the rod a bunch of times. The wire keeps melting and catching almost on fire?. is the battery to big??
The battery is supplying too much current because the 12 gauge wire has such a tiny resistance
Try one of the following:
Use many turns of a larger gauge wire (smaller wire) like 16 or 18 gauge but it should really be enameled wire (sometimes called magnet wire) because magnets tend to get warm and the insulation on rubber or plastic insulated wire takes up a lot of space.
Insert resistor in series with the magnet coil to limit the current. You can make a high power resistor using a steel spring if the coils don't touch each other,
Use a battery with less voltage like a 1.5 volt D cell battery.
Hope this helps. Let me know how things work.
It looks as if you would need over 500 ft of 12 gauge wire to limit the current of the magnet to a value that wouldn't overload the wire and overheat the magnet.
The current with 100 ft of 12 gauge wire hooked to a 12 volt battery is around 8 amps and the current with 500 ft of wire is around 16 amps. This information is according to an online wire gauge table I used. The resistance of 12 gauge wire is about 1.58 ohms per 1000 ft.
The power generated by the magnet coil, in the form of heat, is around 100 watts if 1000 ft of 12 gauge wire is used. You can only operate the magnet for a very short period of time with these lengths of wire since the buildup of heat is very quick.
I'm working on a follow-up video to explain some of these issues about electromagnets.
I'm not sure you should be meddeling with any sort of strong electricicty if you don't even know what a short-circuit is...
Great 👍🏼 video..... will the magnetic 🧲 force be greater using the secondary windings?
No. Although the secondary winding has more turns its resistance is too high to allow a large current to flow. A good electromagnet is balance between coil turns and current. More turns means more resistance which means less current for a given voltage. I wanted to use a low voltage for this particular electromagnet.
so if I slimed down that big hunk if metal would the strength of the electro magnet decrease?
im using the primary coil straight from a microwave so not sure why it doesnt have a resistance of 0.5 ohms
i will get another coil and see if it has lower resistance
Are there any dangers as far as the battery failing or heat buildup that we should watch for in particular? This is great.
Also, I find it odd that as much force that is being generated, when you left the "handle plate" off of the lower piece and applied power, it didn't really POP into place. I would think that this could create a potentially dangerous magnet that might pull nearby metal objects toward it rapidly when the voltage was applied. No? It didn't look like it in the video. Is this a function of the power decreasing exponentially as distance increases?
Use a low voltage for lowest amount of heat generated and longest battery life.
Most magnets like this one have a very short range but can be very powerful at these short ranges. You are right that the forces fall off exponentially as the distance is increased.
Thanks for commenting.
Dorian McIntire Is there an easy way to emanate the magnetic field? I want a magnetic version of the metal detector.
Ryan Metcalfe You really need a coil without a core to sense metal long distances. Proximity sensors, for instance, use small iron cores to sense very close metal objects on the proper end of the sensor.
(*_~)
Dorian McIntire Im a very very beginner in electromagnetism... Actually am a software developer.. But loves electromagnetism very badly..
So you mean the core for stronger magnet and without core it can attract from far or with out core increases the magnetic fields surrounds it?
Is there a way to modify this to function like a bitter magnet? Would welding a hollow iron pipe to it work, or would that just make the magnet taller?
Nice job on this video thank you for putting it together
Wayne Bentz Thank you for watching and commenting!
awesome video!! i read a comment down below about pulling out nails. what do you think would be the smallest size of an area that you can apply tons of pressure?
lester alvarez It's very hard to say. Magnetic pull decreases quickly with (1)-distance from the target and (2)-small contact area with the target. Take a look at the following video to see how much can be lifted with an electromagnet like the one in this video.
th-cam.com/video/cpSHTvzoZII/w-d-xo.html&feature=gp-n-o&google_comment_id=z121ex1xqrecf1am223cf5cgwpfdsbfbg04
Thanks for watching and commenting.
thanks for your response
awesome job
Dorian - man you're awesome man.. so helpful.. god bless man..
Thanks for your inspiring comment.
+sgman73 Thick wire is good. You should be using the coil with larger size wire and fewer turns? Check the continuity on the coil with an Multimeter to make sure the wire is not open-circuited. Of course make sure the battery is good also.
Dorian McIntire how many turns and what thickness
The primary winding for the transformer is already about the right gauge and number of turns. It's typically about 18 - 20 gauge with about 120 turns.
Why does he sound like Wilson from Home Improvement? 😆😆😆
Just the way I roll... and the way I was born. :-)
Hmmmmm im thinking an easy, cheap battery operated magnetic lathe chuck........
thanks for the video and your reply!
I'm trying to find good electro magnets to make a hidden blade, any suggestions
This magnet design acts much like a horseshoe magnet and concentrates the magnetic field near the tip.
To project the field outward futher (but weaker) you will probably want to use a more conventional electromagnet using a straight iron bar with a large coil wound around it.
This should allow the field to reach out futher for smaller objects but with less force.