Wall Clock that takes 1PPS input
Jerry the old IBMs are loud at the 1 minute mark or if pulsed clunk clunk
clunk. Great when you first start them annoying after a bit. But if the
cost is $0 have fun and learn. With respect to 60 hz motors you will need
real power to drive them nothing a micro can do. Something like 20 watts at
some voltage. It all varies from manufacturer to manufacturer.
There was something else on the IBM clocks and don't recall. But I think if
you sent a inverted pulse the clock would go to the top of the hour or was
it that it went backwards.
I suspect there is some good information online.
Regards
Paul.
WB8TSL
On Fri, Jan 3, 2020 at 7:05 PM Jerry Hancock jerry@hanler.com wrote:
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@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@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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