Imagine a plane coil with zero magnetic flux through it. When it rotates in its plane, will an EMF be generated? Everybody would say no. Due to Faraday’s law, no EMF could exist in a coil if the enclosed magnetic flux does not change. Then, how can you explain the experiment in this video?

Please read the article at
Tangential EMF experiment http://pengkuanem.blogspot.com/2014/12/tangential-emf-experiment.html
or https://www.academia.edu/9684360/Tangential_EMF_experiment

Tangential EMF experiment pdf or word with video