Electromagnet Strength

Increasing amperage. But you also should look at increasing your number of windings, and perhaps the size of your rod material as well.

Here is a sight with some tested information you might find usefull:

http://www.usc.edu/CSSF/History/2002/Projects/J0727.pdf

I think it's amp turns on the coil...so more turns or more amps...
But of course more volts will give more amps!
Del

As will higher voltage allow more turns @ same amperage.

AMPS! AMPS! AND MORE AMPS!!!

Assuming that the coil is the constant.

so if voltage goes up then amprege will also? or can one only increase the amps while leaving the volts alone, or visa-versa?

Arthur, the voltage across and current through your electromagnet coil are related via Ohms law, so, yes to your first question, and no to the second. Understanding Ohm's Law is a good thing for someone wishing to tinker with electricity. Have fun!

Tom

If this is hooked to batteries (lets say 12V), Its all about how its wired. If you connect the batteries in parallel (ie positive to positive), you increase the amperage. If you wire them in series (a string of positive to negative so the two remaining leads are one positive and one negative), you increase the voltage. Rule of thumb can be that it will roughly double.

It can also be achived using a good benchtop power supply (the easy way).

There are many other ways this can be achieved, but my guess is that your application is with batteries??

If you connect the batteries in parallel (ie positive to positive), you increase the amperage.

Connecting batteries in parallel does not increase the amperage in the circuit (i.e. the electromagnet.) The amperage in the circuit follows ohm's law. Only if the battery is very small relative to the load will the voltage be pulled down by the circuit, (for example from 12.8 volts to 12.5 with a twelve volt battery... in which case a second battery in parallel will increase the voltage somewhat, perhaps to 12.65). That's a little more esoteric than the questioner wants, I suspect.

Assuming a reasonably constant power supply, the strength of an electromagnet depends on amp-turns (number of amps times number turns).

It depends on amperes but from principle it also depends upon the inductance.

- inductance varies as the square of the number of turns.

- the inductance of a coil increases directly as the cross-sectional area of the core increases.

- Doubling the length of a coil while keeping the same number of turns halves the value of inductance.

- inductance of a coil increases directly as the permeability of the core material increases.

- the inductance of the coil increases with each layer added.

- inductance is dependent upon the degree of linkage between the wire conductor(s) and the electromagnetic field

F = BiL Newtons, if remembered correctly, so either increasing i, the current, or L, the number of turns, or both, will work.

Somewhere there is a balancing act between the size of the wire used and the number of turns. Because the more, thinner wire used, the more resistance is presented to the supply, which in turn (no pun intended) reduces the current.

keep in mind

1) if the iron core is magnetically saturated, you will never get more "magnetic" force out of your coil. The only solution in this case is

-using a "better" material for the iron core.

-using a bigger iron core. increase the diameter.

2) the product, ampere x windings is important. This means,

-with the original coil, make the current go up, by means of increasing the applied voltage.

- make a new coil with more windings on it and adjust the supply voltage in such a way that the current is at the original level