Jack Ganssle, Editor of The Embedded Muse Jack Ganssle's Blog
RSS Feed This is Jack's outlet for thoughts about designing and programming embedded systems. It's a complement to my bi-weekly newsletter The Embedded Muse. Contact me at jack@ganssle.com. I'm an old-timer engineer who still finds the field endlessly fascinating (bio).

Review - Marvelous Magnetic Machines

April 16, 2021

I have reviewed a couple of books by Pete Friedrichs. He's a smart and clever tinkerer who comes up with innovative ways to build things that most of us would never make. Want to make a radio from scratch… including the components like variable capacitors? How about the vacuum tubes? He's got you covered. More info on his first two books is here.

His latest is Marvelous Magnetic  Machines, subtitled Building Model Electric Motors from Scrap. It's all about building small electric motors using found materials. As in his other books, Pete provides step-by-step instructions. Nothing is left out.

Why would you want to make a motor when it's so easy to buy one? Well, why would anyone engage in any hobby? I like astronomy, but the images in my backyard telescope are mere smudges compared to Hubble's art. There's a certain joy in doing things yourself.

(Interestingly, in this pandemic year it seems hobbies are the rage. Many vendors of the stuff we buy to entertain ourselves, for instance telescopes, are backordered months. Demand is very strong. I wonder if these hobbies will persist post-virus. I hope it does. Pete's use of found materials means motor makers won't be delayed by out-of-stock components.)

The book provides a good theoretical grounding in all aspects of this craft. Though EEs know this stuff, most people don't. Permeability, vectors, the right-hand rule and much more is covered in a very accessible way. Though you don't need to understand the physics those with curious minds will appreciate that they can learn from the book as well as build cool things.

And the motors are cool. Quirky. The Texas Motor has what looks like one of James Watt's walking beams. The Christmas Motor is shown turning a propellor, and its magnets are arrayed just like the cylinders on an old airplane's radial engines.

The book is richly illustrated with graphs, 3D drawings and many wonderful color photos.

The book ends with a compendium of parting thoughts that include how to use the sound port on a PC as an oscilloscope (with drawings of the needed cables), test equipment and even balancing your hand-crafted motors.

It's a fun volume that's an easy read. Recommended for those who like working with their hands.

Feel free to email me with comments.

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