# User:Brian P. Josey/Notebook/2010/04/05

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## Variations in Complex Neodymium Magnetic Yoke

From the complex neodymium magnetic yoke from last week I created two variations, a smaller gap, and a "broken" yoke. For the smaller gap, I simulated the additional small magnets that we have, both of which are neodymium magnets with a grade of N42, a diameter of 1/2" and 2/10" long. I placed them in the gap so that they are connected to the flat edge, and leave a gap of .1" between the cone and their edge. The second model, the "broken" yoke, features a break in the magnets on the far side of the yoke from the gap. This break was .5" long.

Brian P. Josey 14:23, 7 April 2010 (EDT) After writing the above paragraph, I was sidetracked by another project, and I didn't finish updating my notebook. Here is everything that I wanted to add, but was unable to on Monday:

### Small Gap

For the small gap, the field is very strong, especially near the tip of the cone. The derivative follows the expected trend. The field intensity as a function of the distance from the tip of the cone is on the left, and the derivative is on the right. For both graphs, the distance is measured in inches, the field in measured in Teslas and the derivative in T/in.

### "Broken"

For the broken yoke, it appears that the field intensity and derivative are similar to the control. The field intensity as a function of the distance from the tip of the cone is on the left, and the derivative is on the right. For both graphs, the distance is measured in inches, the field in measured in Teslas and the derivative in T/in.

Because they both look so similar to the control, I calculated the difference between the broken yoke and the control. Here is the field on the left, and the derivative on the right:

In both cases, a positive value indicates that the broken yoke has a higher value at that point for either the field of the derivative. Also, for both, the length of the measurement has been cut down to 0.1" to focus on the part nearest to the tip of the cone.

I find it interesting that according to my math, near the tip of the cone, the field is stronger for the broken yoke, up to about 0.06" away from the tip.