On Saturday, February 17, 2018 at 10:54:06 PM UTC-5, Ralph Mowery wrote:
In article ,
says...

trader_4 wrote:

AC isn't
consistent polarity in the positive/negative sense. It changes. In
the case of the states, roughly 60 times a second.

I don't think it is "roughly". AC powered clocks keep very good time for
long periods. Though I have heard that sometimes the power generating
companies keep track of how many cycles have taken place over some fixed
period of time and slow down or speed up the generators to correct things.

Jeff

It is sort of roughly 60 Hz. The power company has at times slowed the
frequency some ( maybe 1/2 or 1 Hz) during peak power loads. They will
then raise it a small ammount during lower loads to keep an average over
a long period of time. This keeps all the line powered clocks very close
over a period of time.

Given that the whole grid is tied together, I don't see how one power company could deviate from being at exactly 60hz without either disconnecting from the other grid sources or something very bad happening very quickly.