Home made electromagnet

[GuglioLS]

Solenoids can be made to push or pull, electromagnets are pull only. What exactly are you trying to move and how far are you trying to move it? DC solenoids are easiest to wind by hand. AC solenoids can be made but the winding scheme and armature are a little more complicated best done by machine. Electro magnets are best for holding ferrous metal tight. With low power magnets, the gap between the magnet and the object being pulled toward it, can not be more than a inch or two at most, same goes for repulsion you can't get more than an inch or two of motion. Here is a home made solenoid I once made in an attempt to automate a locking pin for a TPH implement. A linear actuator may be a better choice as they are much more powerful and predictable. The basic concept of making a solenoid is simple enough, putting theory into a home made working solenoid is a bit more challenging:






If interested, check out my original post 360* rotating back blade project PAGE 18 check out page 19 as well, heck, check out the entire project if your really curious.






Google - electro magnets, home made solenoids, How stuff works, Magnetic levitation, etc.. there are tens of thousands of articles of how to make solenoids and electro magnets. So you want to levitate something 20" X 25" ? that's huge, How much does it weigh? Something that big is gonna take quite a bit of power and hundreds of $$$ worth of copper magnet wire. Magnetic levitation is difficult and a huge power hog. Under the best of circumstances, you might get 1/4" to 1/2" height at most of levitation.

Larry

 

[MizztaPeppa]

Solenoids can be made to push or pull, electromagnets are pull only. What exactly are you trying to move and how far are you trying to move it? DC solenoids are easiest to wind by hand. AC solenoids can be made but the winding scheme and armature are a little more complicated best done by machine. Electro magnets are best for holding ferrous metal tight. With low power magnets, the gap between the magnet and the object being pulled toward it, can not be more than a inch or two at most, same goes for repulsion you can't get more than an inch or two of motion. Here is a home made solenoid I once made in an attempt to automate a locking pin for a TPH implement. A linear actuator may be a better choice as they are much more powerful and predictable. The basic concept of making a solenoid is simple enough, putting theory into a home made working solenoid is a bit more challenging:


Google - electro magnets, home made solenoids, How stuff works, Magnetic levitation, etc.. there are tens of thousands of articles of how to make solenoids and electro magnets. So you want to levitate something 20" X 25" ? that's huge, How much does it weigh? Something that big is gonna take quite a bit of power and hundreds of $$$ worth of copper magnet wire. Magnetic levitation is difficult and a huge power hog. Under the best of circumstances, you might get 1/4" to 1/2" height at most of levitation.

Larry

Thanx for the info Larry, Yes basically i want something thats 20 inches by 25 inches to levitate estimated weight between 150 to 180 pounds.
So copper wire around lets say a piece of iron, is the best thing for a basic homemade electro magnet? And if that is true can I get lets say multiple pieces of iron and wrap them all seperately but still be powered from the same source for a stonger push/pull force? Or could i wrap around all them together to get a greater force. Also how big of gauge of wire should i be using.

 

[MizztaPeppa]

Thanx for the info bobodu,I like your joke and also yes i was thinking of having a magnent on the surface of the floating piece of metal or whatever it would be.
So copper wire around lets say a piece of iron, is the best thing for a basic homemade electro magnet? And if that is true can I get lets say multiple pieces of iron and wrap them all seperately but still be powered from the same source for a stonger push/pull force? Or could i wrap around all them together to get a greater force. Also how big of gauge of wire should i be using.

 

[bobodu]

180lbs???

You're sucking a lot of juice!!
I'm not implying you're a drunk...but you are going to be broke from the electric bill.
Watch Modern Marvels "Magnets" and see how much power is required to levitate a frog.

 

[MizztaPeppa]

180lbs???

You're sucking a lot of juice!!
I'm not implying you're a drunk...but you are going to be broke from the electric bill.
Watch Modern Marvels "Magnets" and see how much power is required to levitate a frog.

lol ok i will watch it tonight. ok so heres the thing. maybe itll help you get you guys to see a little more of what im getting at.

This is the hover chair.

HOVERIT - Changing the rules of conventional furniture.

I want that but not a chair. Just a flat surface i can stand on. but i dont want big bulky magnets i want magnets that is flat but about 20 by 25 inches or smaller, whatever necassary to get me able to stand on it. I was trying to get it to be electric so i can turn the hover on and off ya know so when i hit on it raises up. And i will have fishing line at the edges of the magnets or surrounding surface of the magnent so it doesnt fall off when i turn it on. Ya know what I mean? going for the hoverboard look.

 

[MizztaPeppa]

O and also i found these. Would they be strong enough if i had two just like the chair. or could i have an electro magnet on the bottom and one of those on top pushing away.

http://www.magnet4sale.com/home.php?cat=355

 

[rScotty]

I wanted to know if there was a way to use a homemade electromagnet to make something push away from the magnet instead of pull. ........... Please someone respond! Cant find alot of information ANYWHERE!

OK. Here's a definitive answer. BTW, designing magnetic devices is how I make a living so it's a subject I know well. The answer is, "No you can't. Magnetism doesn't work that way". Actually that's not quite true. I should say that you can't make it do any useful work. There are a few materials that are repelled by a magnetic field regardless of polarity. But those materials aren't common and the effect is very weak.
Magnetism isn't the only basic force that works in this lopsided fashion; gravity is another. You can have it as an attractive force, or no force at all...but no one has yet discovered a way to reverse its effect.
rScotty

 

[MizztaPeppa]

OK. Here's a definitive answer. BTW, designing magnetic devices is how I make a living so it's a subject I know well. The answer is, "No you can't. Magnetism doesn't work that way". Actually that's not quite true. I should say that you can't make it do any useful work. There are a few materials that are repelled by a magnetic field regardless of polarity. But those materials aren't common and the effect is very weak.
Magnetism isn't the only basic force that works in this lopsided fashion; gravity is another. You can have it as an attractive force, or no force at all...but no one has yet discovered a way to reverse its effect.
rScotty

im not trying to make something just levitate and stay in one spot by itself im going more along the lines of the hover chair which i put in a reply earlier thats obviously floating but its being held by the plastic parts of the chair. so i want to do that but with an electromagnet to turn it on and off and if i cant turn it on or off and have to use just basic magnets then thats what ill have to do, but ill still need to find strong enough magnets to support 150-180 pounds. Which according the magnets 4 sale website the magnets i was looking at have a pull force of 210 lbs which im assuming that the push force would be the same if i had two magnets of opposite polarity. If you respond to this message please respond to everything i said not just one point.

 

[GuglioLS]

The fishing line to hold it all together will not work. Use at least two rigid guide rods (four guide rods, one at each corner would be best) Take a close look at the maglev lounge chairs in the link you provided. They clearly show rods with guide holes to keep it aligned above the magnets. I hope they have a warning about not sitting in them with your wallet or the magnetic strips on your credit cards will be wiped out! Same goes for a pace maker, which you might need after you learn of the cost of copper magnet wire, and the electric bill to power your contraption. Sitting in one of those maglev chairs would be the same as if they were conventional chairs. Gravity will still pull you body down against the chair just the same as any other chair. To me they look like some gimmick for cool-aid consumers with money to burn.

If your really serious, I suggest sixteen of those $88.99 4X4X1 closeout Neodymium magnets with 335 pounds of holding force. Stack 4 of them on top or each other, then place one stack at each corner of your platform. Then make 4 corresponding electromagnets placed above the permanent magnets. Hook the electro magnets to a couple of 12 volt car batteries connected in series and viola - magnetic levitation. As far as how big and how many windings those electro magnets need to be, and just how much force it will lift and how high it will lift it will require some serious Quantum electrodynamics and mechanical calculations. I suppose your budget for this is unlimited and your just wanting to make some sort of magic trick? A little effort on your part in some on-line google searching will reveal the reality of how many windings and how much power your really going to need. rScotty nailed it with "I should say that you can't make it do any useful work." The most practical use of magnetism is to produce electricity, the second is electromagnetic radiation (radio waves) the third practical use is solenoids. The amount of mechanical power provided by magnets is very week and somewhat limited to small solenoids and electromagnets to hold doors closed and moving / separating steel in scrap yards. The Mag Lev train is a waste of money and power, it is very inefficient. The trouble with magnets is they have two equal but opposite attracting poles, so the magnetic radiation is a closed loop that does not reach out very far. Now if you could somehow invent a single pole magnet, you may have something that would revolutionize the world.


Larry

 

[rScotty]

the magnets i was looking at have a pull force of 210 lbs which im assuming that the push force would be the same if i had two magnets of opposite polarity. If you respond to this message please respond to everything i said not just one point.

The push or pull force is maximum when the magnets are touching. Is that what you want? Otherwise the force falls off as the square of the distance between them. As Gugliols says, the big problem is going to be keeping the magnets centered above each other. On the calculations, I don't know whether that supplier is quoting force between two magnets or one and some ferritic material. Either way, go to Arnold - Technology Center and download the spreadsheet on magnetic field strength calculations. That will give you a handle on magnetic strength via calculation....or just buy two magnets, thread them on a rod and graph how much weight it will support and how the gap between them decreases as the weight forcing them together increases. BTW, summing magnetic forces by stacking depends on the magnets and the geometry & diameter to length ratio- but using two won't double the forces. A rule of thumb is that the second one is worth 50% of the first.
Many magnetic buffs use a freeware program called "FEMM". If you have time to model your magnetic circuit the program will answer all of your questions. You can find it at femm.foster-miller.net
rScotty