Check out Bryan Mumfords page.
http://www.bmumford.com/clocks/em2/index.html
Le 08/08/2010 11:14, Steve Rooke a écrit :
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.
Cheers,
Steve
On 08/08/2010, Neville Michie<namic...@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
pendulum
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
standard.
Steve
On 08/08/2010, Don Mimlitch<donm...@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
motors
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
positive
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
common
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
attract
then the arc is shortened and the clock runs faster. Of course my
master
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
regulation.
So the goal of your adaptation is to have precision control of the
current
flow in the positive or negative direction. Others on the list are
better
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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