Engineering Class Project

⚙️ Axial Flux Motor

Spinning chakras 𖣐

Fusion 360 3D Printing Electromagnetics ESC

The Design

What is Axial Flux?

In a conventional radial motor the magnetic field travels outward from the centre of the rotor. Axial flux flips this: the field runs along the axis of rotation, so the stator and rotor face each other like two plates. The magnetic path is shorter and more direct, which gives higher torque and power density. The flat open winding layout also lets air move around the coils naturally.

This geometry is used in EVs, drones, and supercars. Faraday demonstrated the same basic principle in 1831.

When the class project came up to build a motor, I just found this design really cool. It looks like a chakra or a spinning disc. I enjoyed reading about the history of it and wanted to build one.

Axial vs radial flux motor comparison — Axial vs radial flux geometry. In axial designs the field path runs along the axis rather than outward from the centre.

Historical axial flux motor — Early axial flux motor. Faraday's disk experiment of 1831 demonstrated the same principle this design is built on.

The Build

What We Made

Mechanical

1 bearing, 3D-printed shaft
3D-printed rotor discs and independent spool bodies for each winding
Total weight: ~250g
Lightweight and easy to disassemble and rewind

Magnetics

16 neodymium magnets, alternating orientation around the rotor
Doubled up magnets to increase field strength
Axial field path through facing stator coils

Electrical

Six 150-turn coils, 28-gauge copper wire, 2A max per coil
Operating voltage: 15V nominal
Current draw: ~300mA under typical load
ESC for speed regulation and constant voltage supply

The Process

How It Came Together

Everything was modelled in Fusion 360. The geometry came from research papers since proper hobbyist documentation for axial flux motors barely exists. Winding tutorials in particular are nonexistent at this level, so we figured it out ourselves through trial and error.

The shaft went through a few redesigns to find a version stable enough to support the rotor without wobble. We doubled up the magnets on the rotor after testing showed the single layer was not producing enough field strength.

Honestly it came together more smoothly than expected. The most involved part was getting the windings to align correctly with the ESC, but even that sorted itself out. It also felt more engaging to learn when we were doing the unconventional thing.

Sketch of the axial flux motor design — Early sketch of the motor layout showing the axial field path, rotor disc, and coil arrangement.

Axial flux motor assembled — The assembled motor showing the rotor disc, neodymium magnets in alternating orientation, and the hand-wound stator coils.

Axial flux motor from another angle — Shaft and bearing arrangement, showing the spacing between the two rotor faces.

Iteration

Problems Along the Way

Heavy rotor produced low torque. Redesigned it to be as light as possible.
Large air gap between shaft and rotor was limiting speed. Reduced by 1mm to tighten the magnetic coupling.
Uneven shaft tolerances meant it would not spin continuously. Standardised all coils to 150 turns for uniform winding geometry.
Hall effect sensor polling was too slow to keep up with motor speed. Documented as a known limitation for future work.

Working through winding alignment issues during iteration.

The Result

Our Axial Flux Motor in Action

It spins well. Actually, it spins hard enough that it hurt to hold. We pushed the voltage past nominal and it handled it fine. Lightweight, agile, and it works.

The finished motor running under ESC control at 15V nominal.