The SWCC clock time synch coils were wired in series. Voltage varied with
the number of clocks in the circuit. It takes about 300ma to drive the
coil. Do a Google search for "swcc synchronizing coil voltage" to see a
thread where I talk about this on the NAWCC clock message board. Also the
clocks have a mechanical lock out mechanism that will prevent synch if the
minute hand is more than a few minutes on either side of the hour. Send a
pulse too early or late & you'll hear the click but the time won't be
reset. And yes, it is amazing how many years ago people came up with time
sync systems. Some of the early systems used pneumatics to distribute the
On Thu, Oct 15, 2015 at 8:25 PM, Brooke Clarke <***@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
> 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.
>>> 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.
>>> Mail_Attachment --
>>> Have Fun,
>>> Brooke Clarke
>>> Nick Sayer via time-nuts wrote:
>>>> On Oct 14, 2015, at 4:42 AM, billriches <***@verizon.net>
>>>>> 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
>>>>> 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
>>>>> top of the hour all traffic on the circuit would stop. Exactly at the
>>>>> 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
>>>> That they had something as accurate and widespread as it was so early
>>>> is astonishing.
>>>> time-nuts mailing list -- firstname.lastname@example.org
>>>> To unsubscribe, go to
>>>> and follow the instructions there.
>>> time-nuts mailing list -- email@example.com
>>> To unsubscribe, go to
>>> and follow the instructions there.
>> time-nuts mailing list -- firstname.lastname@example.org
>> To unsubscribe, go to
>> and follow the instructions there.
> time-nuts mailing list -- email@example.com
> To unsubscribe, go to
> and follow the instructions there.
time-nuts mailing list -- firstname.lastname@example.org
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.