[time-nuts] Wall Clock that takes 1PPS input

[Neville Michie]

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

> On 3 Jan 2020, at 05:21, Jerry Hancock <jerry at hanler.com> wrote:
> 
> Hello,
> 
> I looked around but can’t find a wall clock that would take a 1PPS input signal to drive the minutes and seconds.  I’ve made digital modules using a lot of different displays but would love to have a large, 14” or so with a second hand, wall clock that I can drive with 1PPS.  The old IBM clocks, etc I found take a pulse on the minute.  I have an old pendulum clock I can drive with a solenoid but thought I would ask here before going that route.
> 
> Signal levels aren’t important.
> 
> Thanks
> 
> Jerry
> 
> 
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