Common household current...?

Question

To both cases; N. America, and Europe.

Who, where ,when, ,why, and how, was it determined that it would operate at 60 & 50 (respectively), cycles p/sec (Hertz-rate).

Surely, there was a process of factors that brought us to where we are today.

Any thoughts-

Answer 1

The first power systems were DC. But they discovered that AC systems are more effecient, with less loss because you can use transformers to raise the voltage at the source, and drop it back down at the destination.
Higher frequencies always go through a smaller, lighter transformer. So 60 Hz was a good compromise between many factors with the materials available in about 1890.
In more recent years 400 Hz was standardized in aircraft.
Now, very efficient power supplies use frequencies in the megahertz range.
I heard the story that when the first generator was put in service in England, the load was so heavy that they could only get it up to 50 Hz, so they left it there. Of course every plant on a system should be the same, so the reset were added at 50 Hz.
Personally, I think there is some competitive advantage to using a unique frequency, if it keeps customers from buying equipment from competitors, so at least some manufactures chose different frequencies just to establish their own user base.

Answer 2

This is not well documented, and urban legends abound. One thought is that 60 cycle AC is just fast enough that the eye does not perceive a flickering when lighting is powered by it. Another is that 60 is a "natural" number in telling time: 60 minutes per hour, 60 seconds per minute, so why not 60 cycles per second?

http://en.wikipedia.org/wiki/Utility_frequency#History

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Answer 3

According to this paragraph from the wikipedia, the reason for the choice of frequencies is not generally known.

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Very early AC generating schemes used arbitrary frequencies based on convenience for steam engine, water turbine and electrical generator design, since frequency was not critical for lighting loads. Frequencies between 16 2/3 Hz and 133 1/3 Hz were used on different systems, with lower frequencies favoured where loads were primarily composed of motors, and higher frequencies preferred to reduce lighting flicker. For example, the city of Coventry, England, in 1895 had a unique 87 Hz single-phase distribution system that was in use until 1906. Once induction motors became common, it was important to standardize frequency for compatibility with the customer's equipment. Standardizing on one frequency also, later, allowed interconnection of generating plants on a grid for economy and security of operation.

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. What is known is that Westinghouse in the US decided on 60 Hz and AEG in Germany decided on 50 Hz, eventually leading to the world being mostly divided into two frequency camps. Frequencies below 50 Hz gave noticeable flicker of arc or incandescent lighting. Westinghouse decided on 60 Hz before 1892 and AEG decided on 50 Hz by 1899. Tesla is believed to have had a key influence in the choice of 60 Hz by Westinghouse. The first generators at the Niagara Falls project, built by Westinghouse, were 25 Hz because the turbine speed had already been selected before alternating current transmission had been definitively selected. AEG's choice of 50 Hz is thought by some to relate to a more "metric-friendly" number than 60. It may also have been an intentional decision to be incompatible. A plethora of frequencies continued in broad use (London in 1918 had 10 different frequencies), and it wasn't until after World War II with the advent of affordable electrical consumer goods that broader standards were enacted.

Other frequencies were somewhat common in the first half of the 20th century, and remain in use in isolated cases today, often tied to the 60 Hz system via a rotary converter or static inverter frequency changer. 25 Hz power was used in Ontario, Quebec, the northern USA, and for railway electrification. In the 1950s, much of this electrical system, from the generators right through to household appliances, was converted and standardised to 60 Hz. Some 25 Hz generators still exist at the Beck 1 and Rankine generating stations near Niagara Falls to provide power for large industrial customers who did not want to replace existing equipment; and some 25 Hz motors exist in New Orleans' floodwater pumps [1].
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Answer 4

60 cycles made it easier to make clocks.