: 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.

First let me say that this is very interesting and when I first read it I thought to myself that this doesn't seem very efficient. However, on second thought, and mind you I am not a watchmaker, a mechanical engineer or a physicist, it seems to me that there might be more than simply gear ratios involved in the overall efficiency of an auto-winding mechanism. The amount of friction caused by the rotor pivots running in their bearings...the way the mass of the rotor is positioned etc all have an effect on the overall efficiency which is more difficult to measure.

All I know is that if I wear my cal 14 Autavia GMT all day and am normally active it will run and keep time all night while it is off my wrist. I have never managed to be sedentary enough to let the watch go to sleep on me.

Just some thoughts.

JohnCote