[time-nuts] 1903 Self-setting / self-winding clock

Mike Baker mpb45 at clanbaker.org
Sat Nov 1 11:06:42 EDT 2014


This particular 1903 Railroad self-setting/winding
pendulum regulated clock needed only an hourly
signal from a Western Union telegraph line to
provide momentary closure of a relay contact.
This supplied +3 VDC to rewind the spring and also
reset the sweep seconds hand on the hour, every hour.

 From what I have learned about this, the resetting of
the sweep seconds hand is mechanically coordinated
to occur when the pendulum is at either end of its
swing.  It appears that is no way (that I know of) to
guarantee that the "telegraphed" reset pulse would
coincide with either end of the pendulum's travel.

Apparently, the resetting of the sweep seconds hand
will only occur within the time frame of any single
pendulum swing.  I suppose this means that the clock
might be in error by as much as nearly one swing of
the pendulum because it has to reach the end of its
swing before the second hand is reset.

Just guessing here, but I am thinking that all this
clock needs is a 1-second long closure of a relay
contact on the hour, every hour.   I don't think
that leap-seconds are an issue here as the clock
can be manually adjusted for that whenever a leap
second occurs.  So-- it comes back to counting
3600 one-second pulses from a GPS clock...?  Or
am I missing something here...?

Mike Baker

More information about the time-nuts mailing list