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At 02:59 PM 3/5/2004 -0500, Steven C. Barr wrote: >This gets me to wondering...were tape recorders being sold in Toronto >before much of Ontario was changed from 25 to 60 Hz? I know there are 25Hz >electric clocks and record players, and there was a thriving industry >changing these to 60Hz... Interesting question. Back at you: Do you know much about the Utah brand of paper-tape recorders (and/or tape) sold in Canada in the early 1950s? My understanding is that 60/25 is too much of an difference for things to work well and often smoke is emitted when you try it. Here are some interesting 25/60 Hz and Niagara links http://services3.ieee.org/organizations/pes/public/2003/sep/peshistory.html http://www.iaw.com/~falls/power.html I found this at http://www.electrical-engineering-forum.com/ee/Why_5060_Hz_112839.html >Date: 18 Jan 2004 12:16:23 >From: BFoelsch >Subject: Re: Why 50/60 Hz? >What is amazing to me is that nobody here is aware of the fact that 50 >cycles WAS at one time popular in the US. > >When the Hoover Dam was built it provided 50 Hz power to southern >California, which explains why many old electrical appliances were rated for >50/60 cycles long before exports became an issue. I don't recall the date, >but at a point Hoover was refitted for 60 Hz, and little by little the 50 Hz >system vanished. > >The first commercial AC system was 133 Hz, the first long-distance power >transmission was 25 Hz. Southern Ontario, Canada, was exclusively 25 Hz >until 1957, when there was a total and complete conversion. If you poke >around in Toronto you will find 25 cycle color television sets, radios, >clocks, etc. Across the river in Buffalo there is still a tiny 25 Hz utility >system, but its discontinuance has been scheduled for 2007. > >The existing 25 Hz generating capacity is all converted to 60 Hz with static >or rotary frequency changers. If we peg 1957 as the conversion date, I would expect 25Hz recorders... So, here are the numbers for 25/60: A 60 Hz machine, recording on 25Hz power (assuming no smoke which is unlikely) Nominal Actual 1.88 0.78 3.75 1.56 7.5 3.13 15 6.25 30 12.50 A 25 Hz machine being powered from 60Hz would produce (again assuming no smoke): Nominal Actual 1.88 4.51 3.75 9.00 7.5 18.00 15 36.00 30 72.00 The EQs, of course, would be for the nominal, not the actual speed. But I really don't think these machines would work at that great a frequency discrepancy.