# Building an electromagnet can I use different gauge wire if so how

Discussion in 'The Projects Forum' started by brucewayne3210@yahoo.com, Dec 29, 2010.

1. ### brucewayne3210@yahoo.com Thread Starter New Member

Dec 29, 2010
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I have some some small bar magnets and some radio shack enamel coated wire a big screw and some other small parts. My question is this. The radio shack wire is 3 different guages. I want to get 300 turns out of this wire and I will probably need to combine the wire. My question is do i just wrap the first wire then the second wire then on the third one leave one end out then wind the coil then leave the end out and connect those ends to the battery. Or do i need to daisy chain the 3 different guages of wire and solder them together end to end. to make one 28 guage wire connected to a 30 guage wire connected to a 32 guage wire.

Thanks For any help.

2. ### Kermit2 AAC Fanatic!

Feb 5, 2010
3,852
967
If you connect them end to end then you will be limited by the amp capacity of the smallest of them.

You could avoid that problem somewhat by winding it so that the smallest wire is on the exterior and more exposed to the ambient air temp.

What you are looking for is something refered to as AMPERE TURNS. Just the product of the number of coils(turns of wire) you have wound on the magnet and the amount of current you are passing

A volt/ohm meter would be very useful here.

Example:
100 milliamp of current and you have 100 turns of wire. Which would be 100 x .1 = 10 ampere turns. Ideally you want a very large number but also want to keep a balance between number of turns, size of wire and resistance of the wire(due to length)

It's a balancing act, and you must accept a certain degree of heating as a result. To much current for too long and things will smoke and burn.

3. ### CDRIVE Senior Member

Jul 1, 2008
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Before you go any further do yourself a big favor and re-register under a new name. Using your email address as your handle is going to invite email hell into your inbox. After you do that you may want to look at this on-line wire resistance calculator so you can determine how much current you'll be pulling with a given length of wire.

http://www.cirris.com/testing/resistance/wire.html

4. ### marshallf3 Well-Known Member

Jul 26, 2010
2,358
201
Yea, that Radio Shack pack goes down to #30 but there's 200' of it, likewise there's 75' of the #26 and I guess I used the other one up. Compute the length required for one turn and what you're wanting to send through it along with the AWG wire tables to get resistance. The sizes your're talking about don't match what I bought from them last time so I guess it's s cr*pshoot as always when buying from FailingShack.

Alternately I've bought some really good product from these guys: http://www.techfixx.com/

Last edited: Dec 29, 2010
5. ### brucewayne3210@yahoo.com Thread Starter New Member

Dec 29, 2010
3
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Yeah the email address was not a good move. I will have to rethink that one. Secondly @kermit2 Your saying take the largest gauage wire and wind it first and leave the ends out. Then wind the second largest guage wire and leave the 2 connecting ends out. Then wind the smallest guage wire and leave 2 ends out. Then your saying I would connect 3 ends to make one and the other 3 ends to make one to connect to a load a battery a light bulb or whatever????

6. ### Kermit2 AAC Fanatic!

Feb 5, 2010
3,852
967
All I was trying say was the wire will got hot if its hooked to a battery, and by putting the smallest gauge wire on the outside to expose it to the ambient temp will keep it cooler.

Being smaller than the other wires, it will heat up more.

What is the plan again?

7. ### Bernard AAC Fanatic!

Aug 7, 2008
4,240
414
If using 30 ga wire, only need about 25 ft, even less with 32. With 1/4 in bolt, winding length of 1 in.need about 3 layers for 300 turns = about 2.5 Ω or with 1.5V battery = 1W. Stick with a single ga if possible, like 32

8. ### brucewayne3210@yahoo.com Thread Starter New Member

Dec 29, 2010
3
0
Basically I am asking this. I have 3 wires. All three wires are 4 ft. I need 12 feet of wire. Should I put all the pieces of wire together to make one long 12 foot wire or can I use the wires individually and combine the ends or do i even need to do that. Like can I take the first wire wrap it completely around. The same with the second wire. Then the 3 wire leave the starting end out wrap the rest and leave the end out to connect to my load/battery/light whatever. My question is if i have multiple wires how do i use those? String them together, put them on seperately and combine the ends or fully wrap 2 and the last wire will get the first 2 wires conductance and pass it thru to the ends of my last wire which is connected to a battery/load/light bulb etc.

Thanks dudes

9. ### #12 Expert

Nov 30, 2010
16,704
7,343
Just solder them into a 12 foot piece and start winding.

10. ### Audioguru New Member

Dec 20, 2007
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Anything that is manufactured with a solenoid does not use a metal screw as its core.
With a screw for a core then your solenoid will have horrible performance.

11. ### marshallf3 Well-Known Member

Jul 26, 2010
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How does anyone end up with only 12' of wire? Obviously a school challenge?