I don't know of one available commercially, but it would not be hard to modify a standard quartz clock to do this. The standard quartz mechanism uses a motor that advances the seconds hand one second each time a pulse is applied to it. The catch is that every other pulse has to be the opposite polarity. A simple circuit consisting of a single D flip-flop could be constructed to provide this alternating phase functionality.

Matthew

Sent from Matthew D'Asaro's iPhone

It depends on how much work you want to do. I have various clocks driven
off 1PPS (or 2PPS) signals. The cheapest approach is to take almost any
quartz clock with a second hand and drive the coil directly (you need to
pulse with alternate polarities -- i.e. there are even and odd pulses).

I was introduced to this technique by building a Lord Vetinari clock (e.g.
https://www.instructables.com/id/Lord-Vetinari-Clock/ )

I purchased something like
https://www.ebay.com/itm/8-5-INCH-KAPPA-SHIPS-BOAT-YACHT-MARINE-RADIO-ROOM-SLAVE-NAVIGATION-CLOCK/143072681993?hash=item214fcbe009:g:Gn8AAOSwYTtcKPIp
and
it turned out to be a 2PPS clock....

Fun getting this stuff working!

On Thu, Jan 2, 2020 at 3:32 PM Jerry Hancock jerry@hanler.com wrote:

Jerry,

The Chinese NTP server that I've been discussing here lately has outputs
for 1PPS, 1PPM and 1PPH.

The plain vanilla NTP server (no 10MHz.) goes for 150-200.

George, N2FGX

On 1/2/2020 13:21, Jerry Hancock wrote:

I have also solved the same problem I have 4 Seth Thomas quartz clocks with
the red 24 numbers in the display driven by a single driver with
independent advance and hold for each clock. (Needed for multiple time
zones)
Generally reasonably quite. As mentioned they must be driven at a
alternating rate. These were quartz clocks and simply drop the electronics
out and keep the coil. Then have fun.
The clocks were purchased at a bargain store for little and picked up a 5th
as a spare. Do not recall if there were anymore left. If there had been I
would have purchased them 10 years ago.
Have been on the hunt and have not seen anymore.
Also tried to obtain replacement clock motors on the internet. But the
first purchase was not correct do not recall what it was but it was not a
by-phase motor.
Regards
Paul
WB8TSL

On Thu, Jan 2, 2020 at 3:46 PM xaos xaos@darksmile.net wrote:

I’ll have to go read about the Lord Vetinari clock.  He is one of my favorite book characters.

Thanks for all the tips.  I might have an old quartz clock around here to test.  I assume I can just measure the pulse while it is running and generate the same with the 1PPS output.  I’ll have to program a way to advance it, maybe use an Arduino or some other micro and add a few switches.

Jerry Hancock
jerry@hanler.com

I recall using a clock like that. I drove the coil with a 5v cmos type D
flipflop. The coil is hooked to q and ~q with a couple of resistors.
That way you get the reversal of voltage with little fuss.
Don

On 2020-01-02 16:32, Jerry Hancock wrote:

--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

Jerry you are right. See what it does on the original oscillator and match
it. With respect to advancing you can't go to crazy as the unit will
stutter. I want today I can advance the clocks I have at about 15 sec for 1
minute. Maybe faster.
Anarduino will be very fine for what you are doing.

On Thu, Jan 2, 2020 at 6:33 PM Jerry Hancock jerry@hanler.com wrote:

Hi,
I saw the discussion on PPS slaves and spent some time thinking about them.
I have, of course used $3 quartz wall clocks as slaves, but they are rather poor quality.
I remembered that in my collection I had some 40cm dials, probably from an observatory.
These are all 24 Hour dials, but they contain two alternate polarity motor units. One
for seconds, the other for hours and minutes. I had run them in this mode years ago,
they use 24 volts and I had to design a driver, the bi-polar drive being achieved by a
series capacitor, which was driven by a unipolar square wave signal from a GPSDO.
I also have a 10” “Chloride Gents” slave with an unusual bipolar motor driving worm gears.
This is a 12 Hour dial with sweep seconds, driven by a single drive.
This clock then poses the question, “if it stopped how do you correct the dial?”.
There is no clutch and adjusting knob, you cannot touch the hands as the bezel is fixed,
so you would either have to:
(a) set an alarm clock to warn you that the time would be right in a minutes time to start the clock,
(b) Try to double drive it with 2 pulses per second for up to 6 hours,
(c) run it backwards for 6 hours,
or dismantle the slave, which is a major task and likely to cause damage.

This dilemma explains the use of multiple drives in the slaves.

If anyone wants a 40 cm, 24 hour alternate polarity slave without glass and probably requiring
re-bushing of its pivots (which is why, I assume, that they were taken out of service), I have several,
for free, but in Sydney.

cheers, Neville Michie

Thanks for all the input.  My friend Dave has over 300 International Time Recorder master clocks and who knows how many of the old IBM wall clocks.  The slave clocks take 1 pulse per minute and don’t have second hands so they won’t work.  IBM made a wall clock with a second hand and I didn’t know until you guys posted that I can drive them with pulses, assuming.  So I’m going to talk Dave out of one of those clocks assuming he has a couple dozen.  I have a feeling some also used a synchronous motor.  I didn’t think about it until now, but I guess I can also use a micro to generate the 60hz (against my reference) voltage for the synchronous motor.  Has anyone tried that or should I just look for a quartz type only?

Jerry Hancock
jerry@hanler.com