[GTALUG] mysterious restarts

[Peter Renzland]

> On Jun 18, 2016, at 23:12, James Knott via talk <talk at gtalug.org> wrote:
> 
> On 06/18/2016 07:58 PM, Michael Galea via talk wrote:
>> You know of course that the grid frequency is only approximately 60.00
>> hz.  For example, it was 59.97 hz on Friday at around 5 PM.  I have
>> heard rumors that the generators spin the grid up to above 60 hz in
>> the early morning hours to compensate for the drift, but I don't know
>> if thats a fact.  I often see the grid at 60.01 hz, in the middle of
>> the day though.
> 
> That's true over the short term, but long term accuracy is very good.

Yes, because the power plant frequently advances and retards the frequency slightly so that the average is exactly 60Hz.
That makes synchro clocks highly accurate.  IIRC, the German train station clocks are synchronized that way. (50Hz).