Sunday, August 27, 2017

Clock 3 torsion pendulum Q

So the pivots on Clock #3 clearly are consuming energy... I tried the torsion pendulum outside the frame (basically just excluding the pivot).  I counted 70 periods before the amplitude halved... which yields a Q of roughly 315.  But there is considerable wobble since the balance itself is badly out of poise.  I tried to clean this up a bit on the lathe and redrill the center hole (which is misaligned).  Repositioning the suspension hanger also helped, so now the rod spins vertically without much wobble except when the impulse is given.

This seemed to help a bit, as the necessary drive torque has dropped to 1.75 inch-pounds, or about 0.34 mW.  This is about 2/3 as much power as Clock #1 uses, which gives basically one day of runtime with about the biggest weight I'm comfortable with.

Much better, but I suspect that there is still easily fixable power loss due to the wobble at impulse.  If the pendulum weight is placed lower (on a longer rod), this should be reduced, and might help matters further.

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