Clip of my test linear alternator

[joegatt]

Hi.

Linear alternators are coupled to Thermo Mechanical Generators to produce electricity.  I've just set up a crude demo of a linear alternator made from an old transformer.

You can see it at

http://www.youtube.com/watch?v=3HKrxvrJ_JY

I started out by cutting out the central pillar of the laminations using heavy duty shears. This was a mistake as it warped the laminations. I then flattened them out with a binding wrap of adhesive tape. Also, there might have been a way to avoid this modification altogether.

The magnetic field in the core is induced by four flat rare-earth magnets similar to the ones you find in a hard disk drive. The field is alternated by sliding the core from one complimentary pair of magnets to the other.

The LEDs are wired up with opposing polarity to ensure that one of the two lights-up for every half cycle.

In a working model it would be the smaller part, the one carrying the magnets, that would be moved from side to side. Also, low friction would be required, so a ball-bearings slider would be used.

Having the magnets move on their own on a plastic slider would further reduce momentum overheads. And a better layout of the laminations may also reduce magnetic drag. It would be interesting to try to set up a number of additional magnets, outside the slider, in an effort to provide the slider with magnetic levitation.

Regards
Joseph