# Homework Help: Eddy Current transient problem

1. Feb 25, 2010

### Powersprint2

1. The problem statement, all variables and given/known data

For my internship I need to solve a problem with eddy currents involved.

The problem shows a U-shaped aluminum slider (see attachment) with steel plates on the left and right side mounted on it. In this aluminum slider there are 10 magnets (5 at each side) with a strength of ??Tesla each.

The slider can be pulled over an aluminum or, if this isnâ€™t possible a copper plate that has a thickness of ?mm with an external force. This results in a speed of about 4m/s. The space between the slider and the aluminum (or copper) plate is constant and is about ?mm on each side.

The question is now how big is the eddy current force when I pull this slider with 4m/s over the aluminum plate?

2. Relevant equations

?

3. The attempt at a solution

All the question marks in the text above are variables. Therefore I think I have to use Maxwell as a numerical solver for this problem. But I don't know how to use Maxwell for this problem.I did the 2 tutorials (rotational actuator and transient problem) that came with the Maxwell install and I have the schematic 3D model completely in Maxwell (see attachment) with the "standard" values for the variables, but I don't know how to install all the boundaries, excitations and all the other setups on the right way. It seems Maxwell is a very complicated program for a beginner like me.
Could anyone on this forum help me with this problem?

Kind regards,

Arno

#### Attached Files:

• ###### Project2.zip
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2. Mar 15, 2010

### Powersprint2

So, lets start from the beginning because I don't get any feedback for my problem.

I've managed to simulate one magnet with a diameter of 30mm and a thickness of 10mm. The values that where calculated by Maxwell 3D are the same as the ones in real life.
The next thing I wanted to do was to put another magnet with the same dimensions and material facing the other magnet in attracting position 19mm above the first magnet. But then it already went wrong. When I determined the magnetic induction in Tesla, the calculated value is different from the value measured in practice.

I didn't changed the material properties, but nevertheless the calculated value in Maxwell 3D is different then the one measured in practice.

What am I doing wrong?

Thanks for helping me out!