Easy-to-Build Electromagnet lifts over 50 lbs
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- Опубліковано 1 кві 2013
- A powerful electromagnetic made from a microwave oven transformer is demonstrated. The electromagnet lifts over 50 lbs with a AA battery.
Please subscribe, like and share if you enjoy the video so I'll know if I should make more.
WARNING: Make sure you know what you are doing if you recycle parts from a microwave oven. Cut the cord off the unit before opening it to avoid shocks. Do not open the magnetron unit (the square box that produces microwave radiation) since it contains toxic materials. You only need the transformer for this activity. Do not plug the microwave in until the high voltage winding has been removed.
One note about electro-magnets is that they typically cannot pull objects with much force through air. Large forces can only be generated when the magnet is in contact with the magnetic material.
Metal scrapyard electromagnets can only lift heavy objects close to the magnet. Air has a very high resistance to magnetic flux so you must conduct the flux to the material you are lifting through iron or some other magnetic material.
IF YOU EXPERIENCE PROBLEMS WITH THIS PROJECT CHECK THE FOLLOWING:
- The current should be at least 3 amps if you use the correct windings and a 1.5 volt battery
- The coil winding should be less than 1 ohm of resistance
- The battery should be fresh
- The power leads should be large enough to handle the current.
- Try using a car battery for power if the 1.5 battery does not work with your electromagnet
- The magnet will only lift thick iron objects very close or touching the end of the magnet
- This magnet cannot pull objects that are more than a inch or two from the magnet
- The magnet works best with the microwave oven transformer designed for a 120 volt voltage system. Microwave oven transformers designed for 220 - 240 volt systems will not work well.
- If the magnet does not work well for you then you are doing something wrong. It works as shown on the video and for many other who have built it.
- I have no way of knowing what you are doing wrong so if you email me telling me it doesn't work I really can't do much for you except check the above list of potential problems.
• going to the scrap yard
• Electromagnetic crane car
The cartoons showing Wiley characters pulling objects from far away with horseshoe magnets are way off. It would take millions of watts of power to create an electromagnet with enough power to pick up heavy objects through several feet of air like the cartoon at the following link:
• ACME Magnetic Gun
My students have built an electromagnet that can lift more than 400 lbs. running off a car battery. I will show a demonstration of this magnet at a later date. The coil for this magnet is built from a roll of aluminum flashing insulated with paper.
The link below is a rod and shell type of magnet that can usually lift a lot of weight for a small size.
www.duramag.com/products-and-s... - Наука та технологія
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!
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.
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.
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.
Thank you for your efforts and sharing this video.
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
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 UA-cam videos would have you believe their is no such law. ;-)
thanks my friend you gave me a brilliant knowledge about electro magnet
Good, glad you're having better results. Have fun.
Man, that was REALLY something. Thanks a lot for sharing it :)
You're welcome. Thanks for commenting.
thanks for the video and your reply!
Thank you!!!!!!!!!!!!!!!!
I was looking for something like that but so hard to find...
In general this is true. A large core area allows more magnetic flux to be conducted to the object to be lifted.
Enjoyed it Dorian. Thanks
You're welcome. Thanks for commenting and please share. Dorian.
Thanks, very helpuful. I am building a levitator circuit.
+Oliver Smithdeal Please review all the numerous comments I've made on things that can go wrong.. Its my experience that people with problems are using European microwave transformers, low or dead batteries, trying to attract non-magnetic materials, using low current wires and connections, etc. These are all important factors in the proper operation of the electromagnet. Check out the following video ua-cam.com/video/cpSHTvzoZII/v-deo.html&feature=gp-n-o&google_comment_id=z121ex1xqrecf1am223cf5cgwpfdsbfbg04
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.
Nice job on this video thank you for putting it together
Wayne Bentz Thank you for watching and commenting!
Dorian - man you're awesome man.. so helpful.. god bless man..
Thanks for your inspiring comment.
Nice experiment bro :-)
Just awsome thanx u for this great demonstration
+yoan conet Thanks. I really appreciate your comment. :-)
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.
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.
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
shockingly cool
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?
that was pretty cool! thx!
Q StiX You're Welcome! Thanks for watching and commenting.
Pretty cool!
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.
Thanks for your kind help.i would ask when ever i need
i am now your subscriber too :D
Thanks again!
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.
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?
that is damned INTERESTING!
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?
No, as long as the coil is surrounding the center core there should be no problem.
Just be careful that the sharp edge of the core doesn't dig into the core insulation and short it out.
Thanks for your comment.
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.
so if you were to flip the terminals or flip the polarity would you get the piece of metal to jump up???
That is awesome
Meant to say "I only use a AA battery to show how powerful the magnet can be with only a tiny BATTERY". Sorry.
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?
good job
Super Nice
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.
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.
Brilliant
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.
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.
awesome video man, where did you get your core?
beautiful..........................................
+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
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 ;)
great video! thanks! i was wondering if this same step up can be done with a smaller transformer?
Yes, a smaller transformer will work but the electromagnet will not be as strong.
One problem with standard transformers is that the steel laminations are interleaved so they are difficult to get apart. This does not mean it can't be done.
Thanks for commenting
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
0:44 got it right the first time. the secondary is the high voltage winding with thin wire
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.
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.
thanks for your reply
I have worked on it and the coil is now at the bottom, as yours is, but it is very weak. The set up is exactly like yours and i cant figure out why it is so weak. I have measured the resistance at 4.1 ohms and the current at 0.37 amps. Any ideas as to why it is so weak?
Thank you
I'm trying to find good electro magnets to make a hidden blade, any suggestions
Hi Dorian: First off. Thank You for the great video and information. Please allow me to ask You a few questions that are different then others. How can you run this constantly with a six or 12 volt battery without overheating? I prefer the 12 volt. would that increase the pulling strength? On the transformer and wire core, Where would the North pole and South pole be located? Please bear with me. I know little to nothing and am trying to learn. Again Thank You.
It is a difficult balance to increase the strength of the electromagnet without overheating since the magnet is low resistance wire in series with a voltage source. The magnet polarity depends on the direction of the current flow. The center of the coil will be one polarity and the outside metal will be the opposite polarity.
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
my coil has this tape stuff around it, do I need to take this off so the coil can touch the metal? because it is quite hard to take this tape stuff off because it has been glued on
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.
Are there any videos demonstrating how to deconstruct the microwave transmitter?
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?
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
awesome
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.
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!
How would this work if you used the secondary coil instead of the primary?
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.
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.
What's the resistance on the coil (or how much amps is it drawing at 1.5volts)? Also, you mentioned that you could stand on it and try to pull it off. Have you tried lifting more wait with it than 50 pounds? Is 50 pounds the absolute max with 1.5 volts?
I tried to replace the AA battery with a C cell 9-volt battery and it actually seems to have weakened the electromagnet. I made a nearly identical magnet however it's not as strong as I was hoping for. I want the field to be stronger, so both the strength of the magnet and distance from the electromagnet? Any suggestions? Help?
1. are these samped core.
2. can you show how much repulsive force (and repulsive distance) is possible if we use similar two similar electromagnet.
so if I slimed down that big hunk if metal would the strength of the electro magnet decrease?
i can not push my coil back in properly, will having 1/4 of the coil out of the top of the core affect the magnetic strength? thanks
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 ?
If i hook up a higher volt batterie to this will it make the range of the magnet reach further?
I really like this idea. What wattage was the microwave that you pulled this out from? Have you found other microwaves to have similar transformers (i.e. you can take apart)?
It was an 1100 watt microwave. Most transformers with a 120 volt primary coil will work.To take the transformer apart you must break some tack welds using a side grinder or hack saw.
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.
+Alan Gonzalez No, magnets lifting iron is only attractive. Magnets lifting magnets is another story.
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.
We need this technology in snowboard bindings
Thanks we have a microwave at work that's no working I want to do this
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.
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.
I don't understand the reference to the "coat hanger".
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.
can it magnetize far(approximately 15-20cm) objects like cans,nails and etc?
Can it magnetize far(approximately 20cm) light objects like cans,nails and etc?
hello thanks to share a great video, may i ask?
is that a 12V baterry that u used to?
then how long it will work nonstop??
thankyou to share, really want to try it at home :)
your a fucking dumb ass ya know that....ahhhh
Hey Dorian i need to make about 6, 10 pound magnets, how should i go about doing this; how much coil do you think i need, would one of these batteries cover all of them. And would hooking them up in parallel get the most out of the voltages. Also im trying to make them fairly small like an 1/2 inch to an 1 inch diameter. Thank you for the video it was very interesting
Haden,
When you say 10 lbs do you mean magnet weight or lifting weight?
To lift this much weight the construction of the magnet must be similar to the electromagnet shown in the video or even better is something like an iron rod, wrapped with a coil and surrounded by an iron pipe. This type of construction concentrates the magnetic field into the lifting area.
I've posted a link to a similar magnet design in the description area of my video since links are not allowed in UA-cam comments.
You will probably need to run these magnets in parallel. In parallel they will use 6 times more current than a single magnet so any battery will not last long. I would start with at least 25 feet of #20 wire wire per magnet.
Let me know if you have any further question.
Dorian
Thank you Dorian ill let you know how it goes.
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.
Hi! i want to make this magnet for my daughter's school project. for this i had to buy a transformer of microwave. i want to ask what do i need to see before buying it.( i know one shop where i can buy this) but i even dont know how to check if coil is in working condition or not .please guide me, and also tell me how to find coil for powerful magnet . i mean its voltage or something or related to that,Thanks
Hi, Dorian,
Really great video!
How would you proceed in order to drive this with PWM and what you think will be best protection from fly current? I am trying to run a magnet at 60 Hz PWM.
Thanks!
What voltage would you like to drive the coil with? I would drive the coil with power, N-Channel MOSFET that can handle at least 10 amps. Use a 10 amp Schottky diode (removed from a switching power supply) across the magnet to handle flyback.
Connect: MOSFET source to V-, MOSFET drain to magnet, other side of magnet to V+. Anode of diode to MOSFET drain and cathode of diode to V+.
If you don't drive the MOSFET into saturation you can control the energy absorption of the flyback current but make sure you mount the MOSFET on a heatsink for this.
At 60 Hz the diode doesn't have to be a Schottky but these are cheap now.
Dorian McIntire
Thank you for the reply!
I still haven't decided about the voltage but most likely I will start with 24 VDC. I was also considering a MOSFET but I have never played with coils this big.
I will take your advice and try the Schottky diode but having in mind the energy stored in the coils (in your video) and the switching time I expect huge flyback current at the coils when off - 10kV
I also expect to have long charge/discharge cycles and thus not able to achieve 30 Hz.
I hope I am wrong about it :)
Have you ever tried MOV (metal oxide varistor) to deal with high current?
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.
Hi, awesome video !
How long could this kind of AA battery last in these circumstances ?
The answer to that question is in the comments.
Thanks
Yeah, I'm not sure why mine's so weak. What's the significance of the terminals?/terminals on the battery? Any?