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Re: [ARSCLIST] Odd Speed
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.