Perforated Levitating Disk

For this example, we have taken an aluminum disc with 4 holes and placed it upon a solenoidal coil. This disc will at first jump from its resting position, oscillate for a certain period, until it finally levitates at a specific height above a coil -- the coil is using an AC current as its input source.

Symmetry was used to solve only 1/8 of the model. Using MagNet's post-processing abilities, the current density field was generated as if a full model was solved.

Results

Disc

radius = 70mm

thickness = 3mm

initial position = 4mm above the top of the coil's current-carrying section

mass = 154g

Holes

radius = 10mm

location = The center of each hole is 40 mm from the center of the disc, with all four aligned precisely at the 0°, 90°, 180°, and 270° positions of the disc

Solenoidal coil

1250 turns of wire

The current carrying section of the coil has an inner radius of 26mm, an outer radius of 56mm and a height of 55mm

Conductivity

The conductivity of the aluminum disc used in the simulations was 34 x 106 S

Input source

50 Hz, 5A

Video#1 - This first animation shows the dynamic position of the levitating plate.

Note The position animation was generated to be in real time; it demonstrates how the actual device would look when switched "On" in a laboratory.

Video#2 - This animation demonstrates the current density of the plate through a few cycles.

Note The current density animation shows only the startup (0-150ms) of the full solve. It has been slowed down so that the user can see the current density field.