HDD1 DIY Alternator - Part 2

So we now have a nice stack of magnets still attached to the metal backing plates. The next task is to remove the magnets from the backing plates. The magnets are held onto the backing plates with a thin film of adhesive. Warming the magnet slightly does seem to help soften the adhesive and make removal a little easier. Do not try to prise the magnets off, they tend to break! I used the method of holding the metal backing plate in the vice and then bending the backing plate with a pair of pliers, as the backing plate bends the magnet will free itself from the adhesive. Take a look at the photos to see how this works. All of the magnets I removed came off without breaking. The only slight damage was that the protective plating pealed away from some of the magnets, this is not a problem and is purely cosmetic. The plating is only there to stop the magnets from rusting. Once the magnets were free I stuck them onto a heavy steel bar to stop them from flying around the garage.

Hard drive magnets have four poles, at this point I needed to decide if I would use the magnets as they are or cut them in half to make a magnet with two poles. While I would have prefered to use the magnets whole I decided that the two poles were too close together and would make things over complicated. I like to keep things simple so decided to cut the magnets in half, see my blog post here about cutting hard drive magnets.

I now have 12 magnets, each one consisting of two halves stuck together. To make handling and storage easier (and safer) I've stuck the magnets on a spanner (the nearest steel metal object I had to hand). The alternator will be a 3 phase alternator using 12 magnets and 9 coils, so there will be 3 coils per phase. Next step is to mount the magnets on a rotor for which I am using an old diamond tile cutting disk. This has several advantages, its made of steel which is good for directing the magnetic flux, its flat and perfectly round, there are no teeth to be ground off (some people use old saw blades) and best of all it didnt cost anything!

This page was last updated on 16th Jan 2010, I will update the page as some more progress is made, hopefully within the next week or two.