One of those techie concerns of an electric motor, especially a DD table.
https://en.m.wikipedia.org/wiki/Cogging_torque
https://www.brighthubengineering.com/commercial-electrical-applications/67622-what-is-cogging-in-ele...
https://en.m.wikipedia.org/wiki/Cogging_torque
https://www.brighthubengineering.com/commercial-electrical-applications/67622-what-is-cogging-in-ele...