Use of 60 Hertz Frequency in the USA

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

From a standpoint of "cycles per second", and that with 60cps there are 360 rotations in a minute and 360 degrees in a circle, and rotation is a function of a circular movement, or Revolutions, which is measured in Revolutions per Minute, 60cps seems fairly logical and simple to me.

So the real question is, what possessed AEG to decide NOT to use 60cps? Seems to me to have been some sort of mathematical elitist decision based on 60 not being a "preferred number". Sure, 50 goes into 100 easier, but where does anyone use the number 100 when discussing rotation?

Didn't we just do this? In the early 1900s as motors were becoming widespread, power converters were difficult to synchronize at high frequencies, i.e., above 40 Hz. Westinghouse gambled on being able to use 60 Hz (and tesla really liked 60 as a number) while AEG took the safer bet. Both gave decent flicker smoothing.

1500 RPM gives 50 Hz nicely. 1800 RPM gives 60 Hz nicely.

Herman Westinghouse thought it should be 133 and some change, but he couldn't get anything to go that fast.

As I've said before, I'll be willing to bet that some how, some way the selection of 50/60Hz involved an engineer trying to impress a woman.

"Sure, baby...over in France the electricty is 50Hz. But me? I generate at 60Hz. 10 whole Hz stronger. Yeah, I'm kind of a rebel."

*swoon*

Europe's got 50hz

we got 60hz for the same money

it's all about economics

Economics, I'm sure is involved. If I remember correctly, the higher frequencies don't require as large a transformer or motor. Yet the higher the frequency, the harder it is to transmit long distances. So I guess a compromise between the 2 that gives the sensation of no flickering was what they chose.

Look at your computer monitor ... what is the frequency of the monitor. I'd suggest that there is a frequency below which you get eye strain ... Old films were in the 40 frames per second ... and they flickered a bit. But the scenes changed so often that you weren't bothered (much). TV broadcast in color in the NTSC did not turn out too well in Europe. They would up creating a different system (PAL) ... which was better ... at least for the color but slower for the refresh rate. Again, no biggie because the scenes changed so frequently. But why do we now have TV's now with 120hz and more? Because it looks better, you see fast motion clearer.

Incandescent light bulbs flicker too. Think of your incandescent light bulb as a strobe light, that flashes 5 to 6 times faster.

Have you checked your monitor yet ... mine is at 70hz ... I notice a difference at 60 after a hour or so.

I can remember when the first color monitors came out that bragged about 48hz and the headaches. Some people are more sensitive than others I guess. TV is not as bad because the screen changes so frequently ... but on a monitor, there is usually a background that is just a-flickering away at you.

Economics and the flicker ... and what you were willing to compromise on, is my final answer Regis.

"Incandescent light bulbs flicker too" - true, to a very small extent. Generally the flicker in light output from an incandescent lamp can only be detected by measurement with pretty sensitive instruments, even at 50Hz (due to the thermal time constant of the filament).

There isn't any point worrying about 50/60Hz. We will eventually return to DC power for all our home use and distribution.

Almost all the loads around the house are DC as they use an AC to DC power supply. Even the motors in appliances are being switched to various brushless DC controllers.

The distribution with DC is becoming a reality for large networks and could be brought closer to home in the next 20 years. The pole mounted AC transformers will be replaced by DC/DC converters. The power electronics is getting there. The safety problems of DC power distribution will be solved with the solid state switches and protections acting in the uS range. The intelligent grid will be a step in this direction as more monitoring and controls will be needed.

Most alternative energies are better at producing DC than AC. Solar panel, variable speed wind mills, thermal converters...

DC power should improve the system efficiency bu reducing the skin effect and transformer core losses. Hopefully this gain will be larger than the power electronics conduction and switching losses.

Energy storage for home and cars is mostly DC in batteries. A DC network should simplify the energy conversion. DC only electrical supply is increasingly used in "off grid" installations.

Eventually, AC power distribution will become the exception. But not tomorrow. This is introduced in specific applications and will spread if real merits are found.