Making a Powerful Electro Magnet from a Transformer

you know it doesn't matter how old i am i'm always continually amazed by magnets with their magnetic fields i mean they've got this magical invisible force that you can't feel or touch unless you bring two opposing magnets together and they resist coming together or if you flip them around the magnets are now attracted and they snap together so continuing this love of magnetic fields i've wanted to make my own powerful electromagnet now i've seen a few people make electromagnets out of transformers online but a lot of videos i watched haven't gone into detail about how to make the most powerful electromagnet possible with any given transformer or really gone into depth about how to choose the right transformer so in this video we're going to cover all those topics and i'm going to show you how to make a powerful electromagnet out of a transformer this video is proudly sponsored by jirawald duraweld provides quality welding and fabricating equipment from stick mig and tig welders to plasma cutters and cnc machines they also stock all the welding consumables you need to get your job done right so whether you're a diy in the shed like myself or a professional needing industrial equipment jirawald has you covered visit them today at jirawell.co.nz and a big thanks to duraworld for sponsoring this video so how do we go about choosing the right transformer to transform into an electromagnet well magnetic fields are generated when current passes through a wire now the key word there is current current is the thing that is going to dictate how strong the magnetic field is what doesn't play a significant role here is voltage so if our goal is to make a really powerful electromagnet we should select a transformer that has heavy wire for its windings because we're going to be able to pass more current through the wire before it overheats and then ultimately fails but there is a caveat here we do need some resistance so if you select a transformer that has really low resistance on its windings it's going to be hard to control the current so what we actually need to do is select a transformer that's sort of in the half to 2 ohm resistance range here i have three transformers to choose from let's start off with the smallest one [Music] i have my multimeter set to measure resistance and i'll connect my meter to one of the transformers windings this winding measures in at 194 ohms which isn't ideal for this project so let's measure the other winding it measures in at 0.7 ohms making it a viable option for this project let's take a look at the next transformer the windings are more visible on this one the primary winding uses fairly fine wire while the secondary winding has some pretty thick wire which is ideal for making a powerful magnet only problem is this winding has extremely low resistance which isn't ideal for this project my last transformer was salvaged from a microwave oven the secondary winding uses very fine wire so that's automatically out of the running but the primary winding with its heavier wire looks like a viable candidate it measures in at one ohm making it the best option out of the three transformers i have so two out of the three transformers i have are viable candidates to make electromagnets from before i dive into the deep end of the pull i'll start off by experimenting with the smaller transformer i used a pair of vernier calipers to measure the wire diameter which was just under a millimeter using an american wire gauge chart to cross reference my wire diameter this means my wire is 18 awg or thereabouts this means i can run up to nine and a half amps of current through the transformers winding although it will likely overheat if run at full current for more than a couple minutes i'd recommend running no more than 50 of any given current rating to prevent the winding from overheating now you can run an electromagnet off either ac power or dc but in this video we're just going to be using dc power and that's for two reasons reason one is if you don't know the safety protocols around using uh wall ac power then that's an accident waiting to happen reason two is i don't have a method of controlling the amount of current that goes from the outlet to my electromagnet so instead i'll be using one of these this is a typical dc lab power supply and it gives me the ability to fine tune the current and voltage before i start modifying the transformer i connected it up to my power supply and pushed four amps through the winding i wasn't expecting the magnetic force to be powerful and sure enough it wasn't the magnetic field was barely strong enough to pick up the steel bolt [Music] so it's time to start modifying i used a grinder to cut the bottom portion of the transformer's iron core off along with the other winding which we won't be using in this project [Music] with that done it was time to connect it up to my power supply again i have the same amount of power passing through the winding just as before but this time the magnetic field is many times stronger it took a surprising amount of effort to pull the bolt away from the electromagnet one of the downsides of cutting into a transformer's core was the laminated metal sheets began to separate to prevent this from happening to my next transformer i'll weld the laminates together so why did simply cutting away half of the transformer's iron core have such a profound effect on increasing the strength of the magnetic field our little electromagnet generates well that's a good question so first off let's briefly talk about a permanent magnet so i've got i've drawn a permanent magnet here and we've got our north and our south pole and then we've got our black lines with arrows indicating the magnetic field that is generated around the permanent magnet now what attracts a iron object to a magnet in the first place well if i take my chisel here if i have my chisel about this far away from this magnet we can see that the chisel doesn't pass through or intersect with any of the magnetic field so at this distance the magnet's going to have no effect on the chisel but as we bring it closer and closer we can start to see the magnet is intersecting with some of the magnetic field so we're going to start to feel some attraction and then as it gets closer and closer it gets stronger until it touches the magnet and it can't get any closer so moving back to our transformer that we're trying to make into an electromagnet here we have the transformers iron core we have the green representing the wire winding that we pass our current through and then the result is a magnetic field with a north and a south pole now due to the unique shape of a transformers iron core the magnetic field can simply travel through the core from north to south pole just like this now if i bring my chisel back into the equation the problem is the chisel can't interact with much of the magnetic field because the magnetic field is just busy occupied running around within the iron core of the transformer but by simply cutting away the bottom of the transformer like this now the magnetic field has to travel around like this and that means if i bring my chisel back into the equation when we bring it close enough the chisel interacts or interferes with the magnetic field getting attracted to the magnet and bob's your uncle you've got a more powerful electromagnet all right time to scale things up and modify my microwave oven transformer typically mot transformers have a weld on either side holding the e and i sections together separating the two sections is as simple as grinding deep enough to remove the weld and then prying the two halves apart i carefully remove the heavy primary winding from the core and set it aside for later the secondary winding is of no use for this project so it doesn't matter if it gets damaged during removal right so i've got my transformer core all prepped ready to weld i'm not going to be using any filler rod for this i'm just going to be fusing the layers together using my tig welder i'm going to do that in a few different locations to keep all the layers of the core together now i do want to quickly shout out to duraweld for hooking me up with their awesome wave 200d tig welder and also to easy swap gas for supplying me with an argon bottle thank you to both of you you guys are awesome thank you for supporting videos like this on my channel alright let's get tig welding well there we go i don't think i'm going to take home first prizes for the prettiest worlds in the world partly because i don't have great welding skills to lay down those perfect stacked dimes but um welding the layers together like this you can see a lot of soots come out around the welds and that's because of the lacquer between each of the steel plates that's sort of burning off as i weld also welded the shackle onto the top so that i can hook it up with a chain because i do want to strain test this and see how many kilograms it can support later so now i've just got to cut off the excess steel despite my efforts to keep the laminates together some sheets separated and jammed the saw blade [Music] i ended up using a clamp to hold the laminated sheets together during cutting which prevented further blade jamming in hindsight i should have placed welds either side of the cut to prevent the layers from delaminating and jamming the blade but that's hindsight isn't it [Music] now i could reinstall the winding and it's ready to test so to figure out how strong my magnet is i've got a heavy piece of i-beam here it weighs give or take around about 25 kilos so here is the test scenario i've got a chain block suspended on a beam just above me i've got a crane scale here that measures up to 300 kilos and then i've got my electrode magnet on the bottom of the scale and then we're just going to power it off my lab power supply over there so the wire on my electromagnet could handle up to around 20 amps of current but my lab power supply here only puts out about five amps but that'll be enough for preliminary testing to seeing uh how powerful this is or isn't who knows so let's hook up the magnet to my power supply and you can see we're running five amps of current so let's see if it'll lift the beam well it lifts the beam just fine so i guess the next step will be for me to stand on it all right here goes nothing what oh nope don't like that much i don't know about you but i'm impressed i was not expecting this electromagnet to be able to pick up the beam and my weight with only five amps of current running through the core clearly i have to scale up this test to something much heavier all right so we've had the venture outdoors we've got the i-beam over there attached to a car hopefully the electromagnet gives out before it pulls the car backwards i'm sure it will um the electromagnet is going to be run from a 12 volt supply this time so we're going to have almost double the power running through as we did in the previous test same scale as before and a chain block which is attached to a steel pole alright let's get started oh this is getting scary that is tight as and is it any wonder with the scale being maxed out um a little bit of tension has gone off it was at just over 300 kilograms absolutely crazy well i can't go any further than that because that's all my scale is rated for well i am honestly truly staggered at the amount of pulling force this magnet has and i can't be sure of its peak value because i maxed out my scale at 300 kilos so i just know it's at least 300 kilos and above pulling strength now the question is this is a cool electromagnet and all but does it serve any purpose in the workshop like can we put it to good use well if you have any ideas of what i could do with this electromagnet leave them down the comments section below probably the most interesting application that i could use it for in my workshop is making an electromagnetic vise basically it replaces your standard vise that you use on your drill press for example and instead replaces it with an electromagnet vice that you can just turn on and off with a switch clamping your work piece down to your drill press so you can drill holes and whatnot so that's probably what i'm going to be doing in the next video but if you have any more interesting ideas let me know in the comments section other than that thank you very much for watching if you found the video useful please give me a like it helps the channel out massively and if you have any questions leave them down below thank you to my patrons over on patreon you guys are awesome and i will see everyone in the next video bye for now

Channel: Schematix

Views: 202,877

Rating: 4.919848 out of 5

Keywords: transformer, MOT, electro, magnet, electromagnet, powerful, electronics, schematix, duroweld, hugong, welder, tig

Id: DT0QHsN3vcE

Length: 19min 6sec (1146 seconds)

Published: Wed Oct 07 2020