How did they distribute time in the old days?
On 2015-10-14 10:42, Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time business. They
would rent businesses such as banks, office buildings, etc clocks for a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and after the
top of the hour all traffic on the circuit would stop. Exactly at the top
of the hour they would push a pulse of 50 ? volts or so over the line and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate the synchronization signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this point, those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said, would cause the hands to “snap” to 12. The trailing edge of the pulse was synchronized and would release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
Ingenuity was never lacking - a few quotes from
https://archive.org/details/GreenwichTime - well researched and still
available in a later edition - includes many incidents which I found
humorous - the first ilustrating that TWTT long predated Cs clocks:
""Difference of longitude can be determined astronomically or geodesically (by
trigonometrical-survey methods) or, as we have seen, by the transport of
chronometers. One of the earliest examples of the use of this last method took
place during the geodetic operation to connect Paris and Greenwich
Observatories in 1784-8, instigated by Cassini de Thury and conducted on the
English side of the Channel by Major-General William Roy, FRS. In September
1785 Maskelyne sent his assistant Joseph Lindley by post-chaise and
cross-channel packet to Paris and back carrying eight of John Arnold's
chronometers, yielding a difference of longitude of 9 minutes 19.8 seconds,
only about a second too small and agreeing well with the existing astronomical
determinations and the geodetic result. 1 In 1825 a series of rockets was used
by John Herschel and Col. Sabine to connect Paris and Greenwich. The
chronometer method continued to be used for longitude determination of
observatories until the coming of the electric telegraph. For example, in 1843
more than sixty chronometers were sent sixteen times backwards and forwards
between Altona near Hamburg and Pulkowa near today's Leningrad, and the
following year forty chronometers went the same number of times between Altona
and Greenwich. Chronometers were sent across the Atlantic many times to
determine the longitude difference between Harvard and Liverpool Observatories,
from which the difference of longitude between Harvard and Greenwich was
accurately determined. In 1844 the longitude of Valentia Island and the west
coast of Ireland was found in this way, under Airy's superintendence."
"The use of the electric telegraph for this purpose was first suggested by the
American astronomer S. C. Walker and first used in the USA about 1849. As we
have seen, the telegraphic connections between Greenwich and the Continent were
suggested by Airy in 1851, connection with Brussels being established in 1853,
and with Paris in 1854. The longitude of Valentia was redetermined by telegraph
in 1862."
"The first successful submarine cable was laid across the English Channel in
1851. Wales and Scotland were linked with Ireland in 1852, England with Belgium
and Denmark in 1853. By 1860 London was connected with the Indian subcontinent,
one of the longest submarine cables being between Malta and Alexandria, 1,565
miles. But the really exciting prospect was a cable - perhaps more than one
-between Europe and North America. Its main protagonist was the great American
Cyrus W. Field (1819-92), whose untiring efforts provided the impetus
throughout."
"The next year, however, a new cable was successfully laid by the Great Eastern,
taking fourteen days from Valentia to Heart's Content in Newfoundland. To
complete the triumph, the Great Eastern successfully grappled the 1865 cable,
spliced it on to cable remaining on board, and thus provided a second cable
link across the Atlantic.
One of the factors leading to this success was that during the 1866 lay, at the
suggestion of Captain Anderson, the Greenwich time signal was received by the
Great Eastern twice daily by telegraph via London, Holyhead, Dublin, Valentia,
and the cable she was laying, thus enabling her to find her longitude exactly.
This seems to be the earliest example of a ship at sea receiving a time signal
by other than visual means. One of the earliest uses of the new cable was to
redetermine the longitude difference between the observatories of Greenwich and
Harvard University at Cambridge, Mass. This was conducted in October 1866 by Dr
B. A. Gould of the US Coast Survey, in co-operation with Airy."
--
Take care. Thanks, Brian Inglis
The Western Union clocks were still in use at broadcast stations in the
early 1970s. One problem was that the reset pulse and resulting jump in
time would come exactly on the hour, when you were trying to synchronize
with a network news broadcast that began at the network's version of 00:00.
ABC and I presume the other networks would send a tone 10 seconds before
their program started, By listening to the network on the "Cue" channel,
you would have a pretty good idea of when the news would start.
Another system in wide use around then and still somewhat today for
controlling the clocks in a large building was sold by Simplex. The
building would have a master clock (set manually by the custodian or
whoever) that pumped out tones at about 3 KHz over the power lines. These
signals would come out a couple of minutes before the hour, presumably to
avoid problems with events scheduled on the hour. The slave clocks were
designed to run a little fast, and would wait at 58:00 until they received
a tone to restart. I believe there was a special tone that would make the
clock run "fast forward," to deal with longer adjustments for power outages
and DST.
One drawback of this system is that the tones sometimes leak into audio
equipment, and in a quiet room they are often audible through the
fluorescent light ballasts.
On Wed, Oct 14, 2015 at 12:42 PM, Nick Sayer via time-nuts <
time-nuts@febo.com> wrote:
The WU standard time service goes back further than the turn of the 20th
century. It started in 1870.
--
--Jim Harman
And to tie this back to the UPS thread, at university, the Simplex clock sync signal made our Vax 11/730 TOD clock run waaaay fast.
I never figured out if it was using line frequency zero crossings for seconds or if it was leaking as DEC fixed it not long after it was installed. (And it was moved to a different phase of the power system than the clocks...)
On Oct 14, 2015, at 15:55, Jim Harman j99harman@gmail.com wrote:
The Western Union clocks were still in use at broadcast stations in the
early 1970s. One problem was that the reset pulse and resulting jump in
time would come exactly on the hour, when you were trying to synchronize
with a network news broadcast that began at the network's version of 00:00.
ABC and I presume the other networks would send a tone 10 seconds before
their program started, By listening to the network on the "Cue" channel,
you would have a pretty good idea of when the news would start.
Another system in wide use around then and still somewhat today for
controlling the clocks in a large building was sold by Simplex. The
building would have a master clock (set manually by the custodian or
whoever) that pumped out tones at about 3 KHz over the power lines. These
signals would come out a couple of minutes before the hour, presumably to
avoid problems with events scheduled on the hour. The slave clocks were
designed to run a little fast, and would wait at 58:00 until they received
a tone to restart. I believe there was a special tone that would make the
clock run "fast forward," to deal with longer adjustments for power outages
and DST.
One drawback of this system is that the tones sometimes leak into audio
equipment, and in a quiet room they are often audible through the
fluorescent light ballasts.
On Wed, Oct 14, 2015 at 12:42 PM, Nick Sayer via time-nuts <
time-nuts@febo.com> wrote:
The WU standard time service goes back further than the turn of the 20th
century. It started in 1870.
--
--Jim Harman
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
I have been using 2 D cells in series to wind my clock - Every Labor Day I change the batteries! Has anyone used Ken's for a rebuild. Mine is still chugging along - amazing as some of the bushings are ovals and the gears can really move around in them!!
73,
Bill
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Brooke Clarke
Sent: Wednesday, October 14, 2015 2:02 PM
To: Nick Sayer; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] How did they distribute time in the old days?
Hi Nick:
One of my Self Winding Clock Co. (WU) clocks was taken down yesterday for painting.
When put up one of the Ken's Clock Synchronizers was installed and the hands moved to align with the heart shaped cam it uses, but it never worked.
The problem was it used a 4.5 Volt signal which can develop the current needed to pull the sync electromagnet the time constant is far too slow.
I'm going to add a high voltage circuit with series resistor to get the time constant down one or two orders of magnitude. The key to this is a PCB I make that holds 5 each 9V batteries connected in series, so I'll use one, two or more of them to get the time constant down.
http://www.prc68.com/P/45VS.html
Before I had the 45 Volt Stick I was considering getting the needed high voltage by charging a cap a minute or two before the top of the hour and discharging it through a resistor. Here's a video showing that would work.
http://www.prc68.com/I/SWCC.shtml#Experiments_Feb_2014_
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time
business. They would rent businesses such as banks, office
buildings, etc clocks for a few dollars a month. These were
pendulum wall clocks that had 2 #6 dry cell batteries inside that
would wind them every hour or so. The clocks were connected to the WU
telegraph line and for a minute before and after the top of the hour
all traffic on the circuit would stop. Exactly at the top of the
hour they would push a pulse of 50 ? volts or so over the line and it would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate the synchronization signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this point, those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said, would cause the hands to “snap” to 12. The trailing edge of the pulse was synchronized and would release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
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Hi, Brooke,
My self winding clock synchronizes fine on three volts. I built a
synchronizer using a PIC controller with a 32KHz quartz crystal, running
on three volts. You might want to carefully check the coil and
connections on yours. By the way, the winding coils also are running on
three volts.
Don Couch
On 10/14/2015 11:02 AM, Brooke Clarke wrote:
Hi Nick:
One of my Self Winding Clock Co. (WU) clocks was taken down yesterday
for painting.
When put up one of the Ken's Clock Synchronizers was installed and the
hands moved to align with the heart shaped cam it uses, but it never
worked.
The problem was it used a 4.5 Volt signal which can develop the
current needed to pull the sync electromagnet the time constant is far
too slow.
I'm going to add a high voltage circuit with series resistor to get
the time constant down one or two orders of magnitude. The key to
this is a PCB I make that holds 5 each 9V batteries connected in
series, so I'll use one, two or more of them to get the time constant
down.
http://www.prc68.com/P/45VS.html
Before I had the 45 Volt Stick I was considering getting the needed
high voltage by charging a cap a minute or two before the top of the
hour and discharging it through a resistor. Here's a video showing
that would work.
http://www.prc68.com/I/SWCC.shtml#Experiments_Feb_2014_
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net
wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time
business. They
would rent businesses such as banks, office buildings, etc clocks
for a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry
cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and
after the
top of the hour all traffic on the circuit would stop. Exactly at
the top
of the hour they would push a pulse of 50 ? volts or so over the
line and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the
20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up
with a circuit to recreate the synchronization signal for it,
probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The
problem is that at this point, those clocks are quite expensive once
they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once
daily and, as you said, would cause the hands to “snap” to 12. The
trailing edge of the pulse was synchronized and would release the
clock to operate normally.
That they had something as accurate and widespread as it was so early
is astonishing.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
You are really late to this party. Current comptition is how many diffenent types of clocks can be driven with PoE&NTP -- know someone trying to do Nixie with it.
Sent from my iPhone
On Oct 14, 2015, at 09:42, Nick Sayer via time-nuts time-nuts@febo.com wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time business. They
would rent businesses such as banks, office buildings, etc clocks for a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and after the
top of the hour all traffic on the circuit would stop. Exactly at the top
of the hour they would push a pulse of 50 ? volts or so over the line and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate the synchronization signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this point, those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said, would cause the hands to “snap” to 12. The trailing edge of the pulse was synchronized and would release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Nick Sayer writes:
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
See also: http://leapsecond.com/history/usno.htm
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate
the synchronization signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET.
The problem is that at this point, those clocks are quite expensive once they’re reconditioned.
You will find lots of these auto-setting self-winding clocks on eBay. Some are very reasonably priced.
There's a bunch of clock guys out there who play with these and you'll find circuits and information with a google search for words like self-winding clock company or SWCC or Western Union USNO and so on. Start with:
https://en.wikipedia.org/wiki/Self_Winding_Clock_Company
http://www.telechron.com/swcc/swcc.html
http://www.kensclockclinic.com/pdf/PoweringSWC.pdf
http://community.nawcc.org/chapter52/pages/selfwindingclockco
Mitch's (www.telechron.com) and Ken's (www.kensclockclinic.com) sites are superb.
Also, for a screen full of irresistible SWCC photos, try this:
https://www.google.com/search?tbm=isch&q=self-winding+clock+company
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said,
would cause the hands to “snap” to 12. The trailing edge of the pulse was synchronized and would
release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
Oh, Padawan, that's just the tip of the iceberg when it comes to the deep and fascinating history of precise timekeeping.
/tvb
I drive one of my Self Winding Clock Company/Western Union clocks using the NTP server I built using a Trimble Thunderbolt and a Soekris Net4501. I use a GPIO line to drive a simple transistor switch using the same 3 volt battery that I also use do power the winder. The pulse from the GPIO pin is accurate to a sub-microsecond level. By the time you deal with the solenoid and the mechanical issues in the synchronizing arm, it is, let us say, somewhat less precise.
On a side note, I have in my possession the book “Selling the True Time: Nineteenth-Century Timekeeping in America”, http://www.amazon.com/Selling-True-Time-Nineteenth-Century-Timekeeping/dp/0804738742/ref=sr_1_1?ie=UTF8&qid=1444919952&sr=8-1&keywords=selling+the+true+time. Interesting read about railroads driving the need for standard time, as well as college and university astronomers setting up a cottage industry of selling the time. Western Union, with its telegraph distribution of time from the US naval observatory and using the Self Winding Clock Company clocks supplanted the local observatories.
Ralph
AB4RS
On Oct 14, 2015, at 2:02 PM, Brooke Clarke brooke@pacific.net wrote:
Hi Nick:
One of my Self Winding Clock Co. (WU) clocks was taken down yesterday for painting.
When put up one of the Ken's Clock Synchronizers was installed and the hands moved to align with the heart shaped cam it uses, but it never worked.
The problem was it used a 4.5 Volt signal which can develop the current needed to pull the sync electromagnet the time constant is far too slow.
I'm going to add a high voltage circuit with series resistor to get the time constant down one or two orders of magnitude. The key to this is a PCB I make that holds 5 each 9V batteries connected in series, so I'll use one, two or more of them to get the time constant down.
http://www.prc68.com/P/45VS.html
Before I had the 45 Volt Stick I was considering getting the needed high voltage by charging a cap a minute or two before the top of the hour and discharging it through a resistor. Here's a video showing that would work.
http://www.prc68.com/I/SWCC.shtml#Experiments_Feb_2014_
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time business. They
would rent businesses such as banks, office buildings, etc clocks for a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and after the
top of the hour all traffic on the circuit would stop. Exactly at the top
of the hour they would push a pulse of 50 ? volts or so over the line and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate the synchronization signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this point, those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said, would cause the hands to “snap” to 12. The trailing edge of the pulse was synchronized and would release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
Hi Don:
I've got a number of SWCC clocks and 3V doesn't work for any of them. I've done a number of experiments and a higher
voltage and series resistor makes a huge improvement.
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Don Couch wrote:
Hi, Brooke,
My self winding clock synchronizes fine on three volts. I built a synchronizer using a PIC controller with a 32KHz
quartz crystal, running on three volts. You might want to carefully check the coil and connections on yours. By the
way, the winding coils also are running on three volts.
Don Couch
On 10/14/2015 11:02 AM, Brooke Clarke wrote:
Hi Nick:
One of my Self Winding Clock Co. (WU) clocks was taken down yesterday for painting.
When put up one of the Ken's Clock Synchronizers was installed and the hands moved to align with the heart shaped cam
it uses, but it never worked.
The problem was it used a 4.5 Volt signal which can develop the current needed to pull the sync electromagnet the
time constant is far too slow.
I'm going to add a high voltage circuit with series resistor to get the time constant down one or two orders of
magnitude. The key to this is a PCB I make that holds 5 each 9V batteries connected in series, so I'll use one, two
or more of them to get the time constant down.
http://www.prc68.com/P/45VS.html
Before I had the 45 Volt Stick I was considering getting the needed high voltage by charging a cap a minute or two
before the top of the hour and discharging it through a resistor. Here's a video showing that would work.
http://www.prc68.com/I/SWCC.shtml#Experiments_Feb_2014_
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time business. They
would rent businesses such as banks, office buildings, etc clocks for a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and after the
top of the hour all traffic on the circuit would stop. Exactly at the top
of the hour they would push a pulse of 50 ? volts or so over the line and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the 20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up with a circuit to recreate the synchronization
signal for it, probably with a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this point,
those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once daily and, as you said, would cause the hands
to “snap” to 12. The trailing edge of the pulse was synchronized and would release the clock to operate normally.
That they had something as accurate and widespread as it was so early is astonishing.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
I have a synchronome clock built for the British Post Office.
I find that the 10V or so that a USB to serial adapter can produce can
trigger the solenoid, if allowed to charge a capacitor for the intervening
minute. The effect is that I can print a single character once a minute at
a low bit rate and, with a few components but no power supply beyond USB,
step the clock.
A better solution would include a microcontroller to remember where the
hands had stepped to, for automatic recovery after a stoppage.
On Fri, Oct 16, 2015 at 1:25 AM, Brooke Clarke brooke@pacific.net wrote:
Hi Don:
I've got a number of SWCC clocks and 3V doesn't work for any of them.
I've done a number of experiments and a higher voltage and series resistor
makes a huge improvement.
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Don Couch wrote:
Hi, Brooke,
My self winding clock synchronizes fine on three volts. I built a
synchronizer using a PIC controller with a 32KHz quartz crystal, running on
three volts. You might want to carefully check the coil and connections on
yours. By the way, the winding coils also are running on three volts.
Don Couch
On 10/14/2015 11:02 AM, Brooke Clarke wrote:
Hi Nick:
One of my Self Winding Clock Co. (WU) clocks was taken down yesterday
for painting.
When put up one of the Ken's Clock Synchronizers was installed and the
hands moved to align with the heart shaped cam it uses, but it never worked.
The problem was it used a 4.5 Volt signal which can develop the current
needed to pull the sync electromagnet the time constant is far too slow.
I'm going to add a high voltage circuit with series resistor to get the
time constant down one or two orders of magnitude. The key to this is a
PCB I make that holds 5 each 9V batteries connected in series, so I'll use
one, two or more of them to get the time constant down.
http://www.prc68.com/P/45VS.html
Before I had the 45 Volt Stick I was considering getting the needed high
voltage by charging a cap a minute or two before the top of the hour and
discharging it through a resistor. Here's a video showing that would work.
http://www.prc68.com/I/SWCC.shtml#Experiments_Feb_2014_
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Nick Sayer via time-nuts wrote:
On Oct 14, 2015, at 4:42 AM, billriches bill.riches@verizon.net
wrote:
Not milisecond time distribution but time related!
In the early half of the 1900s Western Union was in the time
business. They
would rent businesses such as banks, office buildings, etc clocks for
a few
dollars a month. These were pendulum wall clocks that had 2 #6 dry
cell
batteries inside that would wind them every hour or so. The clocks were
connected to the WU telegraph line and for a minute before and after
the
top of the hour all traffic on the circuit would stop. Exactly at the
top
of the hour they would push a pulse of 50 ? volts or so over the line
and it
would reset the clock to the top of the hour.
The WU standard time service goes back further than the turn of the
20th century. It started in 1870.
I’ve always wanted to get my hands on one of those clocks and come up
with a circuit to recreate the synchronization signal for it, probably with
a Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at
this point, those clocks are quite expensive once they’re reconditioned.
My understanding (perhaps incorrect) was that the sync pulse was once
daily and, as you said, would cause the hands to “snap” to 12. The trailing
edge of the pulse was synchronized and would release the clock to operate
normally.
That they had something as accurate and widespread as it was so early
is astonishing.
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