We once had a major power failure on the Oklahoma State University
campus and the power plant fired up a stand-by generator to get the computer
center and a few other vital spots up and running again.  The trouble was
that the speed governor wasn't too accurate and our mains frequency swung
from 53 HZ to around 65 HZ before they got it settled down around 60 HZ.

        Several people commented upon the flickering or strobing fluorescent
lights so there is a visual difference between 50 and 60 HZ.  It makes
me wonder whether fluorescent tubes made for the 50 HZ market have a longer
persistence phosphor?

        Another couple of observations:  Our UPS's never came back on line
but displayed error indications since the frequency was too far away from 60
HZ for the ferro-resonant transformers to work. It was also kind of strange
to hear the large air handlers in the building gradually speeding up
and slowing down.  I thought I was loosing my mind at first:-)

        At least we did not burn anything up that day.

Martin McCormick