50 Hz v/s 60 Hz 6

[Dan76]

I have a question I hope someone can answer: Why does Europe
(and most of the world) use 50 Hertz AC while the US uses 60 Hertz AC? Who decided these frequencies as the standard and when? I realize this corresponds to 3000 and 3600 RPM for the prime mover (assuming 2 pole machines) but why these frequencies?

 

[jbartos]

Those were "old good times" when things were decided; a lot of freedom, less hustle, etc.

 

[jack6238]

This is an excellent question.
The best answer and discussion is one provided by the superb article by Ed Owen( General Electric-Schenectady) in the History Section of the IEEE Industry Application Magazine, Vol. 3, No.6, Dec. 1997. The title of the article is "The Origins of 60 HZ as a Power Frequency. Additional information can be found in the following publications-which are all mentioned in the article.

B.G. Lamme, "The Technical Story of the Frequencies." AIEE Trans, vol. 37, 1918.

C.F.Scott, The Engineering Evolution of Electrical Apparatus; I. The Beginnings of the Alternating-Current System," The Electric Journal, vol 11, January 1914,pp 28-37.( My note C.F. Scott was also the one that "invented" the Scott-T transformer connection for phase transformation. I've used this connection to convert a three phase sytem to a two phase 4-wire system.)

B.G. Lamme, "The Engineering Evolution of Electrical Apparatus;XXIX, The Technical Story of the Frequencies," The Electric Journal vol,15, June 1918,pp230-237.

D.B. Rushmore, "Frequency," AIEE Trans., vol. 31, 1912 pp. 955-83. Disc. 974-78.

L.B Stillwell, "Note on Standard Frequency," IEE Journal, vol.28, 1899,pp. 364-66.

E.L. Owen, "Mill Creek #1-A HistoricalMilestone," IEEE Industry Application, vol. 3, May/June 1997,pp.12-20. this is another excellent article.

In summary it appears that the best evidence shows that the birth of 50HZ and 60 HZ was related to methods of solving light flicker associated with arc lighting. Because the type of fixtures were different in Europe and the US, the method of solution was slightly different( fixture construction and wind exposeure). In 1891 Westinghouse Engineers selected 60 HZ as their their new power frequency and that same year AEG engineers in Berlin selected 50 HZ as their standard frequency.
These two frequencies remain the principal power frequencies throughout the world. Interestingly enough in 1893 Steinmetz(just transferred from Eichmeyer to Thomson-Houston Companies) was involved in a problem on the system for Hartford Conn. Steinmetz solved the problem which had baffled many others and showed that the problem was caused by a transmission line series resonance which were excited by the 125 HZ power frequency in use. His proposal was to cut the frequency in half of the initial value or 62.6 HZ. GE installed the Mill Creek system in California at 50 HZ(1893). This is discussed in E.L. Owens article mentioned above. GE found itself lagging behind Westinghouse in the sale of AC equipment and changed to 60 one year after the comissining of Mill Creek.

Hope this helps.

 

[jbartos]

Small practical "encore" to "... but why these frequencies?"
1. 60Hz is more practical to rotary 360° divisions. This includes clocks (analog and digital), including the computer processor peculiar frequencies, 3600rpm is more divisible to nonfractional speeds of rotary motion (especially 9 and 12 are convenient), etc. Impractical parts are: bigger watt losses, difficult conversion to decadic divisions, etc.
2. 50Hz is convenient to decadic divisions such as counters, speeds, frequency multipliers, calibrations, gear, linear motors, linear motion in meters, decadic MKSA system (SI), etc. It causes smaller watt losses, somewhat smaller conductor diameters for the same conductor ampacities, etc. Impractical parts: conversion to 360° divisions and usage, smaller speed of normally operated AC motors 3000rpm versus 3600rpm, etc.

 

[Dan76]

Thanks for the answers and the refrences, this question has been bugging me for quite some time.
Gratefully,Dan76