How is this possible? Needs an Explanation!

I took this video about 15 years ago because I could not explain how this was being done,
What you are seeing is a motor spinning what use to be a direct drive turntable at 4100RPMs and somehow an arc that is about 1 -1.5 cm long is being generated.
All the original motors parts have been removed and what's left was just being used as a bearing.