On Jun 25, 3:09*am, "azotic" wrote:
... http://www.cbsnews.com/stories/2011/...ain20074275.sh...

So will shop motors run slower or faster ?
Tom.

Both.

As I understand it, the grid frequency isn't perfectly constant now
and they have to tweak it to make the count of seconds in an hour or
day come out right.

I've built and tuned phase-locked-loops that synchronized to the power
line for precision measuring instruments. At that location the grid
was stable enough that I didn't see momentary frequency variations,
just a lot of SCR switching noise around the zero crossings.

A previous job had been out in the country near a ski resort. Their
200 HP snowmaking machine affected the grid enough that we bought a
generator to run the product for acceptance testing.

jsw