Chris Eddy wrote:
>
> I visited the local power company in western Pennsylvania one afternoon
> (fellow engineers that I know showed me around).  While at the control room, I
> asked them why the frequency reading on a display was not exactly 60 Hz.
> They said that it rarely is, and that they run above or below 60 for some
> period of time to 'catch' back up to where they ought to be.  It sounded like
> a portion of the explanation was hooey, but then, if a zero crossing circuit
> wants to track total time, and it fell behind, it would have to catch up.
> (yea, far fetched).  That was the best explanation I could get.  The moral of
> the story is that one should not count on the power company for any accuracy
> at all.

The power line frequency may never be stable at an exact 60 cps, but
I'll bet a nickel that over a period of time it averages 86,400 cycles
per day.

 - - - Nick - - -