# Ansys Maxwell Magnetic Transient Help

• Khang Vu

#### Khang Vu

I am trying to simulate a linear eddy current brake. To do this, I am modeling my brake as a single magnet moving above an aluminum plate. I plan to measure the drag force on this magnet and calculate my braking force as a superposition of single magnets. Here's my current setup:

Model:
A single rectangular magnet moving along the edge of an aluminum plate such that its cross section is fully covered by the plate's at a top view. My band is a bigger rectangular prism surrounding the magnet and a container object that holds the magnet. The model takes whatever in the container object as a single rigid body; that's what should happen from what I've read online. The magnet's magnetic field is aligned to be in the z direction (towards and perpendicular to the top face of the plate).

Motion setup:
The magnet is moving at a constant speed parallel to the edge of the plate.

Excitations:
The model only accounts for eddy current effects in the plate. It does not account for any eddy current effects in the permanent magnet.

Mesh Operations:
-Skin depth mesh on the plate. I used a frequency of 2000 Hz. This was calculate from the fact that the magnet is moving at 120 m/s
-Internal length mesh inside the plate.
-Internal length mesh inside the band.
-internal length mesh inside the magnet

Currently, I am getting 0 drag force on the magnet and oscillating lateral and lift force.

What equation are you using to solve for the force?

What equation are you using to solve for the force?
I have no idea where to pick equations, but I chose the magnetic transient solver for this problem. The force is given to me by applying a parameter to the magnet object.

I have no idea where to pick equations, but I chose the magnetic transient solver for this problem. The force is given to me by applying a parameter to the magnet object.

Well, it's kind of important to understand the underlying physics in choosing a numerical model. Eddy current breaking is due to power dissipation of the induced current in the conductor. Maybe a simpler model like strips or a coil replacing the aluminum plate might be simpler to analyze by hand? How are the magnet fringing fields handled? My bet is you've left something out if you are getting zero breaking force.

Also, what software is being used?

Well, it's kind of important to understand the underlying physics in choosing a numerical model. Eddy current breaking is due to power dissipation of the induced current in the conductor. Maybe a simpler model like strips or a coil replacing the aluminum plate might be simpler to analyze by hand? How are the magnet fringing fields handled? My bet is you've left something out if you are getting zero breaking force.

Also, what software is being used?
I am using Ansys Maxwell. I don't really see an option to choose the equations behind the model. All I really see is an option to pick which solver to use.