The Internal Components of Positive Displacement Motors (PDM)

This video is the best one i found in the internet which explains the internal components of the Positive Displacement Mud Motors. i really want to thank the instructor who did his best to show and explain the subject in a very simple and understood way. the original video link is
https://www.youtube.com/watch?v=dmnfeBvMLAs

Видео The Internal Components of Positive Displacement Motors (PDM) канала Oil Drilling Channel