MENG 4450, Lesson 3.1. Reading: Kuphaldt, Lessons in Industrial Instrumentation v2.30, section 10.4.1, pages 720 to 722. The air gap field is drawn as its fundamental, one cosine per pole pair, and the flux lines are sketches of where the flux goes, not a field solution. The animation runs about 240 times slower than 60 Hz.