[time-nuts] Re: Power line timing -- setting a clock

[Peter Reilley]

Back in the 1970's I installed Westinghouse power plants
in the US and around the world.   On the control panel
there was a sort of clock that showed the difference between
the AC produced by the plant and some reference, could be
WWV or a crystal, I don't remember.

The "clock" had only one pointer and would advance clockwise if
the plant was running fast and it would move counter-clockwise
if the plant was running slow.   If the pointer went around more
than one turn then you did not really know where you were.

In the US the clocks were not used because the frequency was
determined by the regional dispatcher.

Overseas the clocks were ignored by the operators because no
one used AC driven clocks.   People were just happy to have
power and did not care about the frequency.   If the voltage
was reasonably close the the frequency was more or less correct
that was much better than the alternative, no power.


On 3/21/2024 6:13 AM, Hal Murray via time-nuts wrote:
> All sorts of gear uses the power line to drive their clock.
>
> I picture that a corner of the control room has 2 clocks, one tracking UTC and
> the other tracking the power grid.  The difference between that pair feeds
> into their complicated control system that includes some sort of PLL that
> keeps the power line clock
> tracking UTC.
>
> Is there any way to get a copy of their power line clock?  So I can set my
> power line clocks to a similar offset so they will have a better chance of
> being right tomorrow after they correct for today's offset?  I'm not looking
> for microseconds, just microwave-setting accuracy.
>
> Do they have a graph showing the offset for the last week or month?  I can
> line that up with my graphs.
>
>
>
> Here is a graph from Feb/Mar 2024 where it drifted a minute over 2 weeks.
>    https://www.glypnod.com/TimeNuts/60Hz/60Hz-2024-FebMar.png
> That's 4 seconds per day.
>
>