On Tue, 29 Nov 2005, TKM wrote:

Does anyone remember the Niagara flicker? Power supplied to the Niagara
Falls, Canada area until sometime in the 1950s was generated by one of
the original Falls hydro plants at 25 Hz (I think). The flicker was
very apparent. Motors and transformers were massive and the hum from
electromagnetic devices was a rumble.

25Hz is correct. The last 25Hz pockets of Canada were converted to 60Hz
surprisingly recently, though the exact date slips my mind. I have an old
console radio/record player bearing overlay labelling saying it's been
converted.

DS