Home made Electromagnet ???

Question

Hi ,I need info on how to make an Electro magnet at home .I want it to work on main ,or house current so I also need to know precautions too. Anyone know? Thanks .Moshon.

Answer 1

well there are many different ways to do this. one is by dissassembly of a 120 volt transformer (with secondary windings removed) or ac relay of a known ampere draw. using this method you won't have to worry about the impedance calculations. magnetic design calculations or improper designs or materials to make the ac core necessary to make an efficient 60 hz electromagnet.

now you could wind a core yourself, if you use the right materials, enameled wire, bailing wire cut to a specific core length, or ferrite material, but if you use conductive metal for the core, such as old transformer's, bailing wire, solenoids etc, you want to make sure you insulate the core using paper, cardboard, fish paper etc, so that their is no chance of the core becoming hot. and as a crude rule of thumb without having to calculate impedance, of a 60 hz. if you core has a dc resistance of 120 ohms your going to draw in the vicinity of 1 amp. but shall be somewhat less due to the ac impedance. and remember if you use a solid iron or other magnetic core it will get hot, because of eddy currents generated by ac. and could very easily get hot enough to degredate the enameled wire. and once two windings are shorted, the electromagnet is on a dangerous course of accelerated self destruct. and could quite easily start a fire or worse.

but what you are making the electromagnet for. will determing how much care and sophistication you need. if it is to be used outside or inside inviroment, wet or dry location in a wet location or in weather situations, you might want to consider encapsulating it in high temp epoxy.

and for safety reasons i would not recommend any less than fourty ohms of dc resistance for the core. so that you don't run into the problems associated with higher amperages. and remember that an ac electromagnet will induce current in any metal in it's range.

now if all you need is like a degausing coil electromagnet, you don't need a core. you just need like about 18 to 24 inch circle with about fourty turns of about 20 to 24 gauge wire, wrapped with insulating tape. it also is helpful to have some sort of disconnect switch. for safety and convience.

Answer 2

I think you will have to use rectifiers (power diodes) to convert the A.C. into direct current in order to make an effective electromagnet. While the contributor has the basic idea right, a coil of wire wound around a core of ferrous metal, connecting it directly to A.C. will give you an electromagnet that tries to change it's polarity 60 times a second. I haven't tried it but I don't believe it will be an effective magnet connected to A.C. power. As far as precautions go, insulate all exposed connections, use a three prong cord so you can ground any metal chassis or enclosures you may use, and make sure the diodes are of a proper voltage rating and the magnet wire can handle the expected current draw. Above all if you don't feel comfortable don't attempt it until your sure you know what your doing. It's not worth zapping yourself.

Answer 3

Hi. An iron nail would work if wound with a coil of wire. You would need to insulate the wire from contact with anyone to make it safe.