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3-D Static Force Benchmark (T.E.A.M. Problem 20)

Miscellaneous with MagNet for SOLIDWORKS

This rig was designed to benchmark the static force calculation in electromagnetic problems. It is made from a steel center pole and yoke. The center pole is surrounded by a copper coil excited by a DC current. This problem shows the ability of MagNet for SOLIDWORKS to solve Static Magnetic Problems involving force and magnetic field calculations.

The coil is excited by four different currents ranging from 1000 AT to 5000 AT. The resulting force acting on the center pole is then evaluated. Flux density is also evaluated at two points and over two lines situated in the air gaps between the pole and the yoke.

The following problem is based on the Testing Electromagnetic Analysis Methods (T.E.A.M.) problem #20: 3-D Static Force Problem. The benchmark can be found on the International Compumag Society's website.

Steel center pole and yoke with copper coil

METHODS and RESULTS

REFINED MESH on CENTER POLE

In this example, a refined mesh on the surface of the center pole is necessary to obtain accurate force calculations. The mesh can then be observed and evaluated using the Field View Tab along with multiple filters.

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SPECIFIED B-H CURVE

The specified B-H curve of the yoke and pole material were created in MagNet for SOLIDWORKS and added to the library.

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FLUX DENSITY

When the current is set to 5000 AT, a strong magnetic field is created in the center of the coil.

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FLUX DENSITY RESULTS ALONG LINE

As described in the problem definition, the flux density had to be evaluated along a vertical 10 mm line situated in an air gap between the center pole and the yoke. Here are the results obtained for the four different values of current going through the coil.

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FORCE CALCULATION RESULTS ON THE CENTER POLE

Here are the values of the force calculations on the center pole. The high current coil applies a uniform magnetic field which creates force on the center pole in the opposite direction. In the values presented in the bar graph on the left, the force on the center pole is not exactly proportional to the current. This is the case because the center pole is made out of non-linear permeable steel. As can be observed in the bar graph on the left the force calculations are in agreement with the measured values for this problem.

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