[time-nuts] Regulating a pendulum clock (Jim Palfreyman)
sar10538 at gmail.com
Sun Aug 8 09:14:07 UTC 2010
I was rather more thinking of the setup that Don was suggesting as not
many domestic clocks have a seconds pendulum and it would otherwise
take dividing down a referenced oscillator to the correct frequency.
On 08/08/2010, Neville Michie <namichie at gmail.com> wrote:
> Not many clocks are set up with the gear to modulate the rate,
> but they are all still sensitive to injection locking.
> A tiny rare earth magnet on the pendulum (say 1/2 way down the
> pendulum rod)
> and a coil fed with a stretched (say 250ms long) PPS or for a seconds
> PP2S pulse will pull the pendulum into phaselock with a surprisingly
> small amount of power.
> In fact if you turn off the drive it would keep the pendulum swinging.
> Cheers, Neville Michie
> On 08/08/2010, at 6:00 PM, Steve Rooke wrote:
>> This is very interesting and I wonder if the capabilities of this
>> system being applied to any clock pendulum. If this sort of control
>> any pendulum, then I wonder if it's possible to sync it to some
>> On 08/08/2010, Don Mimlitch <donmeis at yahoo.com> wrote:
>>> Jim Said:
>>>> It also has a coil mounted near the pendulum and a fixed magnet
>>>> on the
>>>> pendulum bar and this coil connects to a box down below with a meter
>>>> and a knob. They are labeled in sec/day. The electronics in the box
>>>> are not clear (being quite old) but by measuring the current in the
>>>> coil it quite simply increases the current one way to slow the clock
>>>> and the other way to speed it up. (I'll admit the physics of this
>>>> doesn't make sense to me - but it works!)
>>> I have a Warren Telechron Master Clock used in Power Stations in
>>> the 20's to
>>> regulate the 60 Cycle so that household clocks using synchronous
>>> would be accurate to seconds a day.
>>> This clock has a similar permanent magnet at the end of the
>>> Pendulum and
>>> a battery connected to a potentiometer to adjust the current flow
>>> or negative in an electro-magnet below the pendulum..
>>> If the bottom of the magnet in the pendulum is "north" and the
>>> current in
>>> the electromagnet is flowing such that its top face is North, then
>>> this will
>>> repel the pendulum causing its swing to be wider and contrary to
>>> knowledge the swing of a fixed length pendulum is not constant
>>> regardless of
>>> the swing. (Huygens discovered this in 1670 an found by forcing
>>> the arc of
>>> the swing to be cycloid instead of circular he could produce uniform
>>> oscillation) Thus if the arc is longer the swing takes more time
>>> and the
>>> clock runs slower.
>>> If the current flows in the opposite direction and the two magnets
>>> then the arc is shortened and the clock runs faster. Of course my
>>> clock isn't as accurate as a Riefler pendulum clock. Also the
>>> magnet in my
>>> clock has lost it's magnetism over time and I can't use this
>>> So the goal of your adaptation is to have precision control of the
>>> flow in the positive or negative direction. Others on the list are
>>> then me at describing how you might achieve this.
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>> Steve Rooke - ZL3TUV & G8KVD
>> The only reason for time is so that everything doesn't happen at once.
>> - Einstein
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Steve Rooke - ZL3TUV & G8KVD
The only reason for time is so that everything doesn't happen at once.
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