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electromagnet A/turn

electromagnet A/turn

electromagnet A/turn

Hello For an electromagnet of given dimensions of coil, to have most possible field what is the best? to increase the number of turns for less current either to decrease the number of turns and to increase the cross section of conductor and increase the current value: nXI with 10A x 100 turns for example is it equivalent with 1A x 1000 turns or 100mA x 10000turns? is it better to make a coil with copper rubber with large cross section and high current or small magnet wire with a great number of turns and small current? thank you.

RE: electromagnet A/turn

You forgot the voltage supply that creates the current. Is the voltage fixed or you will change the voltage to adjust the current?

Assuming the voltage is fixed and the coil dimensions are fixed you will not receive the 1A x 1000 turns or 100mA x 10000turns at the same coil. Using thicker wire diameter (smaller AWG number) will decrease N but the coil resistance will be decrease more. Therefore the N*I with thicker wire diameter will be larger.

One more issue to remember is the inductance, the larger the N the larger the inductance and the slower current rise time.


RE: electromagnet A/turn

You need to consider heat as well. A single turn with lots of amps is the smallest coil. But it might not last too long.

You need to provide more constraints. With enough constraints there is usually only one coil that will provide the NI needed.


RE: electromagnet A/turn

Use square or rectangular wire. (or maybe copper strip)
This will give the largest % copper fill.
Square or rectangular wire is difficult to wind in the smaller sizes, so a fairly large size wire is prefered for winding.
Size the wire to obtain the correct resistance for the power supply that is used.
Amp turns are amp turns. 100 turn and 10 amp is the same as 1000 turn and 1 amp. High amps could cause some magnetic field non linearity due to the start and finish leads.

RE: electromagnet A/turn

For high current/few turns often coils are made from Cu strip (really just heavy foil).
For mid range, square magnet wire is the best.
For lots of turns and very low current then use round magnet wire.

There are all sorts of other considerations.  Heat dissipation, mechanical strength, movement of the windings, ease of connecting leads, and so on.

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