Suitable magnets are now very easy to find and their prices have tumbled in recent years: See our article on buying Neodymium magnets here for some useful resources. However the wire used to make the stator coils (pictured above) in the alternator is not always easy to find and the increasing cost of the copper from which it is made has sent its price up.
What is Magnet Wire
Magnet wire is copper wire which has been coated (or enamelled) with a very thin layer of electrically insulating material – e.g. varnish. This means that it can safely be wound into coils as individual lengths of wire in each coil do not short-circuit one another where they touch. In order to make an electrical contact with magnet wire it is necessary to either scrape or burn off the coating to expose the copper wire inside.
Scavenging Magnet Wire
With new magnet wire being expensive, it is not surprising that many people have turned to alternative sources of wire. Old microwave ovens and power transformers are fantastic sources of magnet wire, and they can often be found in skips or for a couple of ££ at car boot sales. The microwave cooling fan motor alone contains around 30 metres of thin magnet wire which can be put to a good new use.
The large transformer in a microwave (pictured above) has a decent quantity of much thicker gauge magnet wire as well as yet more thin wire.
Microwave ovens also contain a couple of useful magnets in the ‘magnetron’.
Buying Enamelled Magnet Wire
Magnet wire is available in a huge range of gauges and lengths from a few metres for use in amateur jewellery making to spools of 1000m+ for coil winding. For most renewable energy projects you will certainly be wanting to buy the wire by weight on a spool rather than by the metre.
At the time of updating this article (January 2014), typical prices were £16 plus delivery for a 1 Kg spool of 12-24 AWG thickness wire (see our AWG to mm Size Converter), and approximately double that price per kilogram for the thinner enamelled wires (down to super thin 0.080mm diameter wire).
Click here to buy enamelled copper wire now.