I have finally have taken the time to determine the efficiency of the auto winding mechanism in the Buren cal 11 thru 15 movement. I want to start with a comparison of manually winding the movement compared to how many rotations the micro rotor needs to do the same. This is an initial report. I decided to do this because I could not find this information anywhere and there has been a fair amount of discussion on the subject.
Manual winding - 3 to 4 twist on the crown (depending on the person winding = around 360 degrees on the mainspring barrel arbor) is equal to:
Auto winding - 180 or so full revolutions on the micro rotor.
This should run the movement for 6 to 8 hours (from completely wound down) without the second hand engaged. If the second hand is running, subtract around 1 hour.
This example is intended to show the efficiency (or inefficiency) of the auto winding mechanism in this movement. If anyone else has done this test, I would like to hear from you. More later.