By Sheldon Greaves
H. P. Friedrichs, Marvelous Magnetic Machines. Building Electric Motors from Scrap. Artisan Ideas, 2020.
If you are familiar with Pete Friedrich’s earlier books, Voice of the Crystal and Instruments of Amplification, you probably have some idea of what to expect from this newest offering. The previous books describe how to build working radio receivers from practically nothing. Wire, screws, nuts and bolts, and other very common items, none of which come from an electronic supply house. This self-imposed restriction made these books truly unique in the literature of amateur radio and electronics, where they have achieved the status of cult classics. Incidentally, unlike his previous books, this one comes in a beautiful hardback binding, printed on high-quality paper.
Friedrichs is an inventor and electrical engineer currently working as a Principal Engineer with Honeywell. He has five U.S. patents and has contributed numerous technical articles to a wide range of technical magazines and newsletters.
The Next Level…
In a similar way, Marvelous Magnetic Machines shows how to build working electric motors, but this time there’s a difference. Along with the usual excellent how-to, he introduces the reader to the fine art of scavenging the necessary bits and pieces from discarded electronics, and other items that one wouldn’t normally associate with electric motors. By allowing himself the luxury of using electronic and other forms of scrap, Friedrichs takes his work to another level entirely.
When asked how to become an inventor, Thomas Edison is said to have replied, “First, you need a really large junk pile” or words to that effect. That is still true today. Friedrichs introduces the reader to a number of useful sources and strategies for locating and securing the parts needed for these and other projects. He not only describes where to look, but explains how to research different kinds of components to ensure that they will fit the needs of the project at hand.
Learning How It All Works
Besides the pleasure of building something yourself, one of the chief reasons for going to the trouble of building a motor or a radio receiver yourself is to learn how it all works. This takes us to one of the best features (in my opinion) of Marvelous Magnetic Machines as well as his previous books, and that is their excellent educational value. In order to give the reader a firm grasp of what is going on–and to make it much easier to end up with a working device–Friedrichs takes us through some of the fundamental ideas behind moving things with magnets.
His explanations begin with an excellent introduction to what magnets are and how they work, their properties, and the ways in which magnets differ from one another. Friedrichs has a talent for conveying the essential concepts without a lot of excess jargon or unnecessary detail that only confuses the beginner. The math is kept to the what is needed, and carefully explained. The motors in the book are arranged in increasing order of complexity, each one providing an opportunity for explaining additional concepts and ideas.
Engineering Artistry
As should be clear from the two photos I’ve included in this review, his motors are not the rough, ugly product of someone aiming for something that merely works. These motors are beautifully executed pieces that would not be out of place in an art gallery. They show a lot of careful craftsmanship and aesthetics that accompanies a well-designed and built device. His earlier books, Voice of the Crystal and Instruments of Amplification display this same careful attention to detail.
Other Features
Another positive feature of this book is the illustrations. Thanks to a new publisher (Artisan Ideas) to step up the production values, Marvelous Magnetic Machines includes some beautiful color photographs, charts, tables, line drawings, and a number of CAD illustrations using FreeCAD showing assembled and exploded views of various components.
Speaking of software, Friedrichs has an appendix that introduces the reader to the world of open source software, very fitting for the DIY enthusiast on a tight budget, or who simply wishes to indulge the streak of anarchism that lies buried–sometimes deeply–in the heart of most DIY’ers.
A second appendix lists a number of reference materials, of both the online and dead tree variety. These resources address the needs of both the raw beginner and the seasoned inventor or engineer. One item that I liked about the listings here is that in a number of cases, Friedrichs includes a brief note explaining why a particular reference was included.
Conclusion
This is not a book for a weekend. There is a tremendous amount of information packed between the covers of Marvelous Magnetic Machines. It is not really an exaggeration to state that the book is almost a self-contained course on electric motors, their construction, function, and use. One problem with books that describe projects drawn from the scrap pile is that everyone’s scrap pile (or thrift stores or garage sales) will be different. You can’t usually replicate the project in the book. Fortunately, Friedrichs concentrates on the basic ideas and principles that make his motors work, and explains them in a way that will help the reader find their own way through the subject, and on to their own projects. And, if you follow the books tips on acquiring parts, you’ll probably amass a pretty decent junk pile as well. For my part, I look forward to Friedrichs’ next offerings.
To order a copy (and you should), click here.