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

[Ted Langdell]

Hi, Park,

See the link about

http://en.wikipedia.org/wiki/Preferred_number

The voltage differences are discussed in a number of things I googled  
earlier today.

Try "Alternating Current" or AC Voltages around the world" and see  
what appears.

Ted

On Apr 10, 2010, at 8:29 AM, C. Park Seward wrote:

> 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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Ted Langdell
Secretary

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