Print

Print


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.