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

[Jerry Hancock]

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?

> On Jan 3, 2020, at 2:59 PM, Neville Michie <namichie at gmail.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
> 
>> 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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Jerry Hancock
jerry at hanler.com