Sandro Ronca
Physics and Mathematics of the Rotating Magnetic Field
From AC motors to waves and harmonics — an e-book that students learn from by experimenting with 14 interactive cards.
Sandro Ronca
From AC motors to waves and harmonics — an e-book that students learn from by experimenting with 14 interactive cards.
These are two of the interactive cards from the book, exactly as students use them while reading. Start the animation, tick the boxes, move the sliders. They work on desktop, tablet and phone, with no installation.
Interactive card 2.1 — A two-pole synchronous motor: the three-phase currents, the field of each phase, their sum and the rotating poles. Tick Description to see the parts of the machine.
Interactive card 7.1 — A small function plotter: write a function of x and t with the keypad, press PLOT and start the time. Can you find a wave that travels without changing shape? Then measure its phase velocity and wavelength with the stopwatch.
The three-phase system (card 2.1-A): how the EMFs are generated, star and delta connections of generator and load, phase and line currents. Then the induction motor (card 3.1): slip, rotor currents and torque appear as the load is applied.
Every chapter is built around cards like these. Each one comes with the text that explains what to look at and why.
Courses on electrical machines, electromechanical energy conversion, AC circuits and applied electromagnetism, from first encounters with the rotating field to the mathematics of traveling waves and spatial harmonics.
The cards can be shown in class on a projector, assigned as guided exploration, or simply left to curious students. The prerequisites are basic AC circuits and trigonometry; the book recalls what is needed.
Download the free sample (EPUB) — the introduction and the first two chapters.
The cards run inside the e-book in readers that support scripts. On a computer we recommend one of these free readers; on iPad, iPhone and Mac, Apple Books works too. In other readers each card appears as a picture with a link that opens it in the browser.
If you teach a related course and would like to evaluate the book, I will gladly send you the complete e-book. Please write from your institutional address and mention your course.