Hi Mike:
The hourly synchronization 1 second wide pulse turns on a second prior to the
top of the hour and off at the top.
But . . . . it's not a low voltage pulse, but rather each clock is in a series loop where the external resistance is
more than an order of magnitude higher than the internal resistance of the solenoid. That's because T = L/R for
inductive circuits and using an external resistor lowers the time constant. When you use a DC source that has just
enough voltage to pull in the solenoid the movement is very sluggish, but when there's an external resistor in the
circuit the action is snappy and much stronger (to the point where for slave clocks it makes the difference between
advancing and just wiggling without advancement).
See for example the video at:
http://www.prc68.com/I/SWCC.shtml#SC
An energy efficient approach might be to start charging a large cap a minute prior to the top of the hour then discharge
it through a series power resistor using a one second wide pulse that ends at the top of the hour. Note it takes more
power to correct the clock if it's a couple minutes off than when it's on time, so there needs to be a lot of power in
the pulse.
PS the synchronizer by Ken's clocks uses a 4.5 V supply and is too weak to work
on my clocks.
PPS adding the series resistor is also needed in teletype circuits and for the
same reason, to get faster action.
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Mike Baker wrote:
Hello, Time-Nutters--
A friend has a vintage oak-cabinet pendulum movement
clock made by The Self Winding Clock Company some time
around 1903. The company was formed in 1886. By the
early 1900's era, this clock was known for its relative
accuracy. These clocks were pendulum controlled and
powered by a rather small and frequently reset
mainspring that was wound hourly by a set of 1.5 VDC
dry-cell batteries. In 1890 (?) the Naval Observatory agreed
to telegraph standard railway time. Western Union,
which also owned the Self-Winding Clock Company, sold
these clocks to the railroads and sent the hourly time
coordinating signals around the country by telegraph.
My friend has one of the railroad clocks that has the
Western Union Telegraph hourly resetting option.
My friend thought it would be an interesting juxtaposition
of technology from two different eras by creating the
momentary 3-volt resetting pulse every hour from a
GPS disciplined oscillator / clock pulse.
I am wondering what the easiest approach to this might
be? I suppose I could take the 1-sec pulses from a
GPSDO (Trimble Thunderbolt ?) and count 3600 of them
to generate a momentary reset 3VDC signal. In any event,
I thought I would pass this by the Time-Nuts gang to see
if any feedback is available as to what the least complicated
(simplest) way might be to accomplish this.
Mike Baker
***************
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