[DonRotolo]

Some key factors are the magnetic pull required and the voltage available.

The current in the wire multiplied by the number of turns, and the core size and material, determines the magnetic pull. But, the bigger the current, the bigger the wire must be and so you can't fit as many turns. The number of turns and the wore size determines the bulk resistance of the coil, and so you need a certain voltage to maintain a certain current flow.

Maxwell's equations explain it, but without some college level math under your belt, they won't help much.

So, what kind of pull, what is the power source, any size limitations, etc.. and we;ll get you through it.

Google "electromagnet"


Don