Notes from Windward: #68


Axial Flux Alternator

exploring an evolving technology

  March 27:

     We've been studying the various ways that we can hook up an electrical generation unit to our steam engine, and came to the conclusion that an axial flux alternator was what we wanted. Of special interest was the work of the kind folks at While much of their work involves building alternators for wind power installations, the reasons why axial flux alternators work well in wind applications also apply to steam powered systems.

     For a great page outlining the process of adding an axial flux alternator to a steam engine, Click Here.

     After conferring with the Otherpower guys about our application, we sent off for a set of 24 rare earth magnets and a coil of #13 magnet wire, which arrived today. Unpacking the magnets was a hoot, as they remind one of a Road Runner cartoon in that any knife within two feet of them will launch itself across the counter and bond quite securely to the magnets.
Annie checks out the strength of the rare-earth magnets

     One of the reasons why we went with this technology is that out of all the options, this is the one that seems most practical for the post-Industrial village to use. An axial flux alternator has no moving parts, such as brushes, to wear out, or bearings that will need replacing. Whereas a automobile type alternator needs to turn at 5,000 rpm, our axial flux is designed to turn at 500 rpm, a speed which the steam engine can handle indefinitely.

Notes From Windward - Index - Vol. 68