Remixed Homopolar Motor

by davefhunt in Workshop > Science

4270 Views, 48 Favorites, 0 Comments

Remixed Homopolar Motor

2015 10:41.jpg
Homopolar Motor

I've been using these for years in physics lessons - it is a good demonstration of Fleming's left hand motor rule.

There are a couple ofproblems though.

  1. It can be difficult to see the motion from the back of the class.
  2. It won't run unattended.

I remixed this from here

Ingredients

2015 10:41.jpg
2015 10:42.jpg
  1. A retort clamp orsome other way of holding the battery up;
  2. A washer;
  3. Two rare earth magnets;
  4. A spinner;
  5. A wire;
  6. A wood screw. (must be ferrous Metal).

Make a Spinner.

2015 10:41.jpg
55e02eb14936d420ec001170.jpeg
55e02fdb2e7fb610bf0009ad.jpeg

I found an image of a spiral (in the public domain). I cut and pasted it into an editor, and printed it out.

I then cut two circles out and glued them back to back.

Assemble the Motor

2015 10:41.jpg
IMG_2369[1].JPG
2015 10:41.jpg

Assemble the motor in the usual way as shown in the original instructable,

The differences are

1. the addition of the spinner and the washer that makes it stick to the magnet.
2. The use of the clamp to hold the battery. (So you don't have to)
3. A second rare earth magnet is used to attach the wire to the top of the battery

Normally if you were making one of these motors you would try to make everything as well centred as possible.

In this case you actually want to make the assembly slightly off centre. This means as the disk spins, the lower magnet will tend to lose contact with magnet. Thus it will spin slower and in an eye catching wobbly manner.

Finished Product

2015 10:42.jpg
2015 10:41.jpg
2015 10:41.jpg
2015 10:41.jpg
2015 10:41.jpg
2015 10:41.jpg

The finished motor should run unattended