Re: Synchronome amplitude

Tom Van Baak


Your theory sounds right. The support & frame does indeed play a large role. I found this out with a free-standing pendulum and was able to increase the Q dramatically by successively adding lead weights on top of the frame, thereby increasing its rigidity. Therefore one has to be very careful about interpreting experiments where only the bob mass is changed.


----- Original Message -----
From: John Haine
Sent: Sunday, January 27, 2019 2:27 AM
Subject: [synchronomeelectricclock] Synchronome amplitude

I don't know if anyone in this group reads "Horological Science News", but 18 months back there was a small furore in that publication arising from some measurements made on the influence of the mass of the bob on the amplitude of swing. The person who did the measurements used the results to attack the conventional theory that the amplitude depends only on the resistance and is independent of mass. I got interested in this and did some analysis of his results and concluded that one primary cause of the variation could be small distortions of the frame caused by the weight of the bobs he was using (which varied from 4 to 15 kilograms!). Some of the measurements included looking at the movement of the support bracket from which I could estimate its stiffness. Basically a heavier pendulum would move the pallet down relative to the gravity arm, reducing the effective drop and energy increment.

Now I have a Synchronome I'm hoping to make some measurements myself using a dial indicator once the clock is screwed to a wall, but if anyone finds themselves in a position to make such a measurement it would be very interesting. For reference I've uploaded a copy of my article to the files section.

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