Re: Temperature compensating a pendulum clock?



In article <jenfgv$btj$1@xxxxxxxxxxxxx>,
jeff_wisnia <jwisniaDumpThisPart@xxxxxxxxxxxxxx> wrote:

We have a very nice pendulum wall clock in our kitchen which has the
type of movement where a battery powered electric motor winds the spring
of a traditional type pendulum movement.

The clock keeps excellent time in the summer, but during the cold months
of our New England weather, when we let the temperature in the part of
the haouse where the clock is located drop into the 50s during the
night, the clock gains about 3 minutes a day.

I presume this is due to the pendulum shaft shortening with temperature
and I can sort of compensate for it by adjusting the bob downwards a
bit, but it's still not accurate enough to suit my taste.

I was wondering if I could fasten one end of a strip of bimetal
scavengened from an old thermostat onto the back of the bob in such a
way that the free end moved downward as the temperature dropped and with
some trial and error tuning end up with a "temperature compensated
pendulum."

Comments appreciated, I'd really like to keep the existing movement in
that clock rather than jump to a quartz movement.

Thanks guys,

Jeff


I know little in general about clocks... but remember hearing of better
clocks being compensated.

Check this, in particular the section on thermal compensation about half
way down;

<http://en.wikipedia.org/wiki/Pendulum_clock>

Erik
.



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