[QuadList] Mains frequencies==(was Quad - progressive or interlaced?)

[C. Park Seward]

Thanks Ted. Interesting. But I still don't know why 60 was not a "preferred number"?

Now what about 110 vs. 220???

Best,
Park

C. Park Seward
2" Quad and 1" "C" transfers
Visit us: http://www.videopark.com




On Apr 10, 2010, at 7:54 AM, Ted Langdell wrote:

> On Apr 10, 2010, at 3:23 AM, Trevor Brown wrote:
> 
>> I would like to say that 405/25  and 625/25 in the UK was forward thinking
>> Ie 24 FPS films could be played at 25FPS and nobody would notice,
>> but it was because of the mains frequency and if you locked to it picture hum would not move
>> I don’t know why the mains was 50hz, I don’t think we planned it that way in anticipation of television coming  
>> but you have to win one now and again.
>>  
>> Trevor
>> UK Member
>>  
> 
> 
> 
> The reason why we have incompatible AC power frequencies is this:
> http://en.wikipedia.org/wiki/Utility_frequency
> 
> Though many theories exist, and quite a few entertaining urban legends, there is little certitude in the details of the history of 60 Hz vs. 50 Hz.
> The German company AEG (descended from a company founded by Edison in Germany) built the first German generating facility to run at 50 Hz, allegedly because 60 was not a preferred number. AEG's choice of 50 Hz is thought by some to relate to a more "metric-friendly" number than 60. At the time, AEG had a virtual monopoly and their standard spread to the rest of Europe. After observing flicker of lamps operated by the 40 Hz power transmitted by the Lauffen-Frankfurt link in 1891, AEG raised their standard frequency to 50 Hz in 1891.[5]
> Westinghouse Electric decided to standardize on a lower frequency to permit operation of both electric lighting and induction motors on the same generating system. Although 50 Hz was suitable for both, in 1890 Westinghouse considered that existing arc-lighting equipment operated slightly better on 60 Hz, and so that frequency was chosen.[6] Frequencies much below 50 Hz gave noticeable flicker of arc or incandescent lighting. The operation of Tesla's induction motor required a lower frequency than the 133 Hz common for lighting systems in 1890. In 1893 General Electric Corporation, which was affiliated with AEG in Germany, built a generating project at Mill Creek, California using 50 Hz, but changed to 60 Hz a year later to maintain market share with the Westinghouse standard.
> 
> 
> 
> 
> Ted Langdell
> Secretary
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