Hello here is a good video showing the motor/gen parts and how they work. For a description of how the 4 modes of operation work there are other videos with schematics that show this more clearly. But, if you wish to see the actual parts then this video is good or at lest OK. You may wish to zip half way thru the video where he starts to do some close ups. And I am not sure why after showing himself once or twice he did not zoom in on the actual Motor/gen to get a better look at the parts.
https://www.youtube.com/watch?v=dqM3YXEf1js&t=1654s
https://www.youtube.com/watch?v=dqM3YXEf1js&t=1654s
