[LEAPSECS] Of stepping motors and leap seconds

[Tony Finch]

> On 7 Feb 2019, at 19:33, Rob Seaman <seaman at lpl.arizona.edu> wrote:
> 
> The Corpus Clock is entirely mechanical (and analog), isn't it?
> 

No, it is much more complicated than that. Let me c&p the relevant bits of my old blog post... https://fanf.dreamwidth.org/96948.html

> The clock's spring has to be particularly strong in order to overcome the momentum of the large escape wheel that goes around the outside of the clock. When prototyping the clock this caused a serious problem: the force of the spring is transmitted through the escapement to the pendulum, making it swing higher and higher and eventually breaking the clock. Taylor overcame this problem by adding a regulator, which also serves two other functions: it produces the clock's erratic behaviour that plays tricks with observers, and it listens to the MSF time signal to synchronize the clock every five minutes. (Taylor confirmed to me after the talk that these are all functions of the same mechanism. He also said that the hollow pendulum bob is not in fact "massive and weighty" as the book says, which answered my question about conservation of momentum.) I'm not sure how this is consistent with his assertions that the clock is purely mechanical - would it work if the computer regulator broke? News reports about the clock's teething problems suggest that it's pretty vital. I wonder if the maintenance periods this week and back in January are for software patches rather than mechanical adjustment?

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at

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