The Homebuilt Dynamo by Alfred T. Forbes reviewed by Mark Newell The Homebuilt Dynamo book presents complete details for what I consider to be the ultimate in homebrewed power projectsÄbuilding my own low rpm (revolution per minute) generator. A low rpm generator is ideal for simple and efficient generation of electricity from sources that often are in the 100 to 800 rpm range such as wind, hydro or, as Alfred and Julia Forbes do for their daily electric needs, a bicycle. As Alfred says himself, "The Homebuilt Dynamo is not another 'do-it-yourself' book, it is simply a careful diary with photographs, detailed working drawings, and text of how I built myself a low speed, low voltage, three-phase permanent magnet alternator with internal rectifier diodes which makes it, in effect, a direct current generator. To avoid a long winded description, I have substituted the word 'dynamo'." Alfred and his wife Julia were "New Zealand back to the landers" in 1967. They lived for three years with kerosene and oil lamps before tiring of smell and danger. The idea for the book was born because of the high cost of bringing power to their door. Deciding to make their own, Alfred was unable to find any books on building small dynamos and decided to document the learning and building process as he built his own. The result is a 182 page journal filled with over 300 photographs, charts, and drawings detailing the construction of a 1 kiloWatt (28 Amps and 36 Volts DC) generator at 740 rpm. In building this generator, no casting, welding, or soldering is required as well as no previous knowledge of electrical machines. Construction requires nothing but hand tools. It's not, however, a project for the first time builder; if you have problems making a box out of wood and getting the corner to match up then I recommend practicing this first. Precision and patience are required in the cutting of materials and winding the coils. For the mechanically adept there is plenty of information, a source list for materials, and patient explanations of the underlying physics that make it a challenging, educational and rewarding project. Alfred includes descriptions of how he built some of his tools and construction equipmentÄa precision-cutting diamond saw for cutting magnets to size, a high power magnetizer to magnetize ceramic magnets, a small precision sheet-metal, wire winding jigs, and several test instruments. The appendix contains details of tests made on the Homebuilt Dynamo and data for scaling up the dynamo to obtain large increases in output and efficiency. The only drawback I can find is the $65 price (including shipping from New Zealand) attached to this plethora of practical knowledge. Overall it is a great lesson of the art of self sufficiencyÄthe patience, resourcefulness and determination needed. This is what home power is all about! Access The Homebuilt Dynamo, Alfred T. Forbes, ISBN 0 9597749 0 4 1987; 182pp. $50 ($65 postpaid) from Todd-Forbes Publishing, P.O. Box 3919, Auckland, New Zealand. Reviewed by: Mark Newell, c/o Home Power, POB 520, Ashland, OR 97520 ù 916-475-3179