# Difference between revisions of "User:Brian P. Josey/Notebook/2011/02/08"

Project name <html><img src="/images/9/94/Report.png" border="0" /></html> Main project page
<html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>Previous entry<html>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</html>Next entry<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html>

## FEMM Model Results

[User:Brian P. Josey/Notebook/2011/02/01| Last Tuesday], I attempted to make a model of my newest electromagnet in FEMM, however it failed to work. At the time, I thought that it could be an issue with my computer, until I tried it again. On Thursday, I recreated the model on the lab computer, and it too failed to work properly. After playing with the precision and mesh size, I was able to create a working model. Here is a representative picture of it, taken directly from FEMM:

2.5 Amps solution This image is the solution created by FEMM of my electromagnet with 2.5 Amps running through the magnetic wire. The colors represent the magnetic field density |B| in Tesla. The magnet is represented so that the 325 turn portion of the magnet is the upper large box, while the 25 turn portion is the lower flat box. Clearly the field strength is greatest near the 325 turn portion. The data collected for today was taken from the boxes on the center left portion of the image.

From this model, I then calculated the magnetic field as a function of the current running through the magnetic wires. From this, I then calculated the force acting on a magnetic dipole placed in the center of the magnet. This time, I am going to do something a little different; I created two different fields over which I took data. The first is a line running along the central axis of the magnet that is 10 mm long. This line is centered at the center of electromagnet, giving 5 mm to either side of the center. The derivative from this is recorded as 10 mm Derivative (T/mm) in the table below. Then I cut this line down again to focus on only the central 4 mm. This data is written down as 4 mm Derivative (T/mm) in the table below. Here is the data: