Frame / Scaffold for Battery-Magnet Homopolar Motor

Frame / Scaffold for Battery-Magnet Homopolar Motor

Warning: Be safe and observe all safety rules.

Update: Added a cone spiral scaffold, which works as expected but needs a bit more copper wire. It also tends to move up and down slightly, which is a great problem for further exploration.

The homopolar motor is an interesting electronic experiment to play with. Using an AA battery, some copper wire, and a few neodymium magnets, one can quickly build a working motor for educational demonstration. However, it can be hard to balance the copper wire frame, esp. for beginners.

This design is a scaffold (45 mm x 60 mm), which allows the copper wire to be pushed into the grooves for easy balance. One can just focus on the contact between the wire terminals and the magnets.

Materials Needed.

1. An AA battery (rechargeable is fine).
2. About 10 inches (240 mm) of copper wires (18 or 20 gauge).
3. A few neodymium magnets (about 15 mm in diameter).
4. A 3D-printed frame

How to

1. Push the wire into the frame and fix the ends.
2. Then, adjust the ends of the wire so that they lightly touch the magnets to complete the circuit. A circular loop is fine.
   
3. Check to make sure the positive terminal of the battery can touch the wire at the top.
4. If necessary, use a screwdrivet to push it out a little bit.
5. Be safe and look into electromagnetism.

Questions

1. Is it a short circuit? Why or why not?
2. How does one change the direction of the spinning wire?
3. What would happen if the magnets are flipped at the bottom of the battery?
4. Why do the parts get hot?

References

1. https://en.wikipedia.org/wiki/Homopolar_motor
2. https://www.ligo.caltech.edu/LA/system/media_files/binaries/270/original/Homopolar_motor_vs2.pdf?1453822070