Segmented Electromagnet Cores

[rukiddingme]

Is there any difference in magnetic field strength between an electromagnet with a single solid core and an electromagnet with a core that has two or more segments?

Thanks in advance.

[gyulasun]

Hi,

how do you mean the segments?  Lengthwise, radialwise? Best would be to make a simple drawing, even in MS Paint.

[rukiddingme]

http://i288.photobucket.com/albums/ll198/koretech/Cores.gif

[gyulasun]

Thanks for the drawing. Wished to know how you meant.

I do not think it would give any advantage, especially not if there are air gaps left between the segments.

In electromagnets, the core's permeability and the number of turns that mainly counts. Attract force depends on B² so the core should have high saturation flux data, and you have to consider the cross section area of the core. 
And if you have to switch the electromagnet on and off with a certain frequency (even if with only 5-10 Hz), then you have to start to consider eddy current losses in the core.

Have you seen this post by member DMMPOWER here:
http://www.overunity.com/index.php?topic=4624.msg96814#msg96814

He sums the flux of the permanent magnet with the flux of the electromagnet, so a stronger electromagnet is the result for the same input excitation. Be careful to choose the core material to avoid saturation from the summed fluxes. And a good sing is that when the coil is off the flux of the permanent magnet is closed within the core, not much or no leakage to the outside.

If you use the Search function on this Forum with key word electromagnet, you may find further hints on them.
Gyula

[rukiddingme]

Thanks for the reply.

I was more concerned if the multiple segments would be a detriment, I wasn't looking to gain anything from this.

Would the segments cause any decrease in the magnetic field?