What do you want the electromagnet to do?
How much does it need to pick up?
Will it always pick up "steel" and iron?
Will it need to be protected against rust and corrosion?
Do you have a good power supply available?
Do you need the electromagnetic to completely "clear" of residual magnetism, or will a little retention of a magnetic field be OK for your project?
What is important? Size? Weight? Cost?
Duplicate cost to build a second magnet? To build 150,000 duplicate magnets?
Cheapest and easiest for regular dumb projects is a soft iron core wrapped with many thousand turns of the insulated conductor to carry the DC current, next is mild steel.
Ok thanks I don't know a whole lot about electric motors but some reason I have become very interested in them lattley.
Its a one off electric motor just building it for fun so cost isn't a real issue but I figured that if I am going to build one I might as well build and awesome one.
Does the whole mass of the stator contribute to the power of the magnet or is it just the part that is wound with wire, eg would a solid metal stator generate the same energy as say a carbon fire stator fitted with metal fingers wrapped with wire, assuming every thing else was equal.
Thanks for your feed back
Within a motor there is a magnetic circuit which is sort of complementary to the electric circuit, and just as critical to the operation of the motor. You need to read up on magnetic circuits, including 'air gaps', and disassemble some motors.
Hints:
Carbon fiber will be of absolutely no use to you.
Motor magnetic circuits are very often made of laminated silicon steel. To find out why, read up on 'eddy currents'.
If you want to gain a hands on understanding of electromagnets don't start with a motor, start with some simple magnets.
Wind a bar magnet an a horse shoe magnet. A bar magnet will have a larger air gap than a similar sized horse shoe magnet.
Hint: Magnetizing force is dependent on Amp turns. As a first order approximation, twice as many turns means twice the resistance, half the current and the same number of Amp turns.
Magnet strength depends more on the wire gage.
More turns gives less 12R loss in the magnet.
More turns means more induction.
Bill
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"Why not the best?"
Jimmy Carter
You're an interested hobbyist, not an electrical engineer. Which is not a problem per se, but we strongly recommend you pick up a few simple electrical how-to books from your local library before starting. Scouts, hobby shops also have starter kits that will help.
