The technical story of the frequencies

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ron_o

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THE TECHNICAL STORY OF THE FREQUENCIES by Benjamin Garver Lamme a Westinghouse engineer.

http://books.google.com/books?id=Qw...al+Story+of+the+Frequencies&output=text#c_top

Finally an answer as to why 60hz was so chosen. According to Benjamin Lamme 60hz was just a compromise. 125 and 133 Hz would have been impossible to produce with a combustible engine at the time. At 80 RPM they would have needed some 200 poles in order to produce these frequencies.

There was much infighting as to what frequency would win. There was a battle at one time between 25 and 60 Hz. But in the end 60Hz came out the overall winner because of technological advances and such. And 25Hz did have problems with lights flickering as such.

Nothing said about Telsa. I always assumed his or other calculations were based on mathematical findings. However, it was through empiracal experiments that proved 60Hz was sufficient to handle most every problem. And Lamme even goes on to say that perhaps different frequencies could be produced for naval ships, because they are a place unto themselves, like the airplanes and such of today.

It's an interesting read and I believe it's about as definitive as you can get in regards to the truth of the matter. I'm not sure if 60Hz is so much better than 50Hz, because if that were the case then why wouldn't 70Hz be better than 60Hz? Or maybe I'm thinking about it wrong.

Enjoy the read.

Lamme's Wikipedia article:
http://en.wikipedia.org/wiki/Benjamin_Garver_Lamme
 
I personally believe it is even less technical than as described by Lamme. Europe was all but settled on 50hz (German AEG), General Electric settled on 40hz. Westinghouse decided to go with 60hz. Why not all be the same? Why does a Ford Mustang look different than a Chevy Corrvette? Why are Mcdonald's hamburgers not quite the same as Burger King's?

Its about establishing a "brand" or an identity separate from your competitiors. However, if one particular company gets so big and so powerful that it begins to influence everything about their market, you have to either change to survive or die continuing with the old.

Once Westinghouse won the Niagra Falls Hydro-Power and Buffalo Transmission Project AND at the same time started taking HUGE chunks out of the lighting and appliance market from Edison / GE, all eventually had to go with 60hz here in the US. The same applies to all the individual companies in Europe.

The middle frequencies (40-60) make the most sense, but there is really nothing special about any one.
 
Bryan,
I thought that the Edison/GE systems of the time frame when Tesla/Westinghouse did the Niagra project were DC systems.
 
glene77is said:
You have piqued my curiosity.
What about 40-60 Hz makes most sense?
Click to expand...

I certainly could be wrong but I seem to recall reading it is a trade off between the voltage drop characteristics and the physical size of transformers, generators and motors.

For example 400 hz is used in aircraft as the electric motors and transformers can be smaller (lighter) and voltage drop is not a real issue.

At least that is what I remember reading here. :smile:
 
iwire said:
I certainly could be wrong but I seem to recall reading it is a trade off between the voltage drop characteristics and the physical size of transformers, generators and motors.

For example 400 hz is used in aircraft as the electric motors and transformers can be smaller (lighter) and voltage drop is not a real issue.

At least that is what I remember reading here. :smile:
Click to expand...


That's the whole point. I'm not sure if most people are just repeating old myths or they are talking facts.

The real issue if the day was that there needed to be a standard, and there were technical difficulties with higher frequencies. It was settled upon eventually that 60Hz suited most any situation. Having that standard they stuck with it.

The book was written at that time. Lamme redisigned the induction motor and died in 1924. In 1903 he became lead engineer of Westinghouse. I'd say he's a pretty darn credible reference.

http://en.wikipedia.org/wiki/Benjamin_Garver_Lamme
All information from the wikipedia article came from:
Benjamin Garver Lamme: Electrical Engineer; an Autobiography, by Benjamin Garver Lamme, Adolphus Mansfield Dudley
 
I believe that most Telco's still use 25 Hz to ring your land-line phones. I'll have to measure it with my Fluke next time I have the test meter in the house .... ;)
 
Teslas Waldynclyffe is only 5 min from my house if you need me to run over there and test something just pm me. Too bad morgan had it blown up. Buildings are still there though. I drove past it again today leaving the rocky point st patricks day parade looking at history that few knows exist. It is for sale in case anyone is interested.
 
50Hz has the merit that it makes calculations easier. A half cycle is a nice even 10ms, not 8.333333333333333........
:wink:
 
Jim Dungar
Not only that, wasn't Niagara a 25Hz installation?


Well Jim i read this niagara falls power plant turbine 65,000kva 13,000volts
3 phase 25 cycle 107 rpm generators and they had 12 large magnets in each . so it was 25 hertz first ? comments take care
 
The "middle frequencies of about 40/60 cycles" are indeed the best for general use.

Lower frequencies produce an obstrusive flicker on lamps, especialy low wattage higher voltage lamps.
Lower frequencies require larger more expensive motors, generaters and transformers for a given KW duty.
Low frequencies limit the rotational speed of alternators or induction motors.

High frequencies increase the capacitive and inductive losses in both cables and overhead lines, apart from the power wasted, undesirable insulation heating occurs in cables at higher frequencies.
Transformers and other equipment tend to emit noise at twice line frequency, 120 cycles in the USA, at a higher line frequency this noise would be more of a nuisance since the ear would be more sensitive to say 200 cycles, than to 120. Higher frequencies would also interfere with telephones to a greater extent, due to greater coupling between power and phone circuits.

In the early days lower frequencies were used because commutator motors were not satisfactory on higher frequencies.
Lamp flicker was only a minor concern since a DC supply was sometimes used for lighting, and anyway the flicker was still better than an oil or gas lamp that would be used otherwise.

If the most suitable frequency was being chosen today (ignoring the capital tied up in existing equipment) Then IMHO a higher frequency would probably be chosen, perhaps 100 cycles.

The greater losses on long transmission lines would be avoided by the greater use of HVDC for bulk transmission.
Interference with telephones would be much less of a concern than in the past, due to the widespread use of digital and fibre optic systems.
Power could be generated at slightly greater efficiency and lower capital cost by steam turbines or gas turbines which could be run faster than the present 3,000/3,600 RPM limit.
 
Just as a point of interest the 25 Hz system was still in use in New YorK City until the 1970s. It was used to supply the rotary converters that supplied the original DC system in New York. When the last of the 25Hz generators was retired, they used frequency changers to convert 60 Hz to 25Hz. The system was finally retired when the New York Transit system finally upgraded their subway signalling system. Just the facts.
 
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