Why power supplied is 110v and 60hz?

Actually the supply is 240/120 volts. You have available 240 volts for some appliances and 120 volts for others. 60 cycles is standard.

ok but why is it just these values in the USA and even over the world, I want to know the technical reason.

Anyway thanks Wareagle.

This is a question that many people have tried Because when AC power distribution was invented here in the US, 110V was the DC standard voltage that Edison was using at the time, so Tesla used that same voltage level in order to allow people who were using electric lights to use the same devices. He chose 25Hz to begin with, but it made lights visibly flicker. So he later changed to 60Hz so that electric clock motors would run at the right speed.

When the Europeans finally caught up with the US and started distributing AC power, they chose 220V 50Hz. You would have to ask some old dead German whay he did that, makes no sense to me. Good luck trying to find a valid reason, but most likely it was just to be different.

hi

Fourtuntly, I have found the answer to my question in the Internet, you can see the answer in the attach. Maybe its lettel bit long but it has useful information .

http://www.madsci.org/posts/archives/2001-04/988615032.Sh.r.html

The original reason of using 120V and 60 Hz was a practical one:

120 is a multiple of 2,3,4,5,6,8,10.12,20,24, so usually when designing a transformer to convert this voltage to a lower one, the ratio of the turns necessary is an integer.

Also, if in DC, the nominal voltage of an elementary cell is 1.2V, for which 120V is a multiple.

The same is valid with the frequency of 60 Hz.

The EU standard voltage of 220V (recently upgraded to 230V) as well as the frequency of 50 Hz has been selected differently.

For the voltage, considering the fact that distribution goes usually in 3 phases, thus the range covering both that voltage and a 1.73 x voltage, it has been (probably) considered that a 220V (together with its 1.73 x value (380V) would cover most power requirements for this range.

The initial selection of 120V (in both areas) has been considered as both safe for humans (distances, isolation characteristics, etc) as well as the power trasmitted.

When power to be transmitted increased, in order to use the existing wiring (same wire size - assuming the wire insulation was OK), the most efficient way was to increase the voltage.

Definitely, to distribute electric energy at a higher voltage is more efficient, but all appliances have to be replaced by appliances with the new voltage rating.

Effects of 60Hz versus 50Hz would be: less flickering, lighter equipment at the same power rating, etc.

Please see also: http://en.wikipedia.org/wiki/Utility_frequency

In the US, Voltage and frequency were determined by what Brian Arthur has called the Law of Increasing Returns, that is, when competing technologies enter the market, one sometimes gains an earlier advantage in market share and becomes the de facto standard without regard to technical superiority. An example is the triumph of VHS over Beta for video recordings.

The 60 Hertz frequency was initially determined by the Westinghouse Electric Company. Herman Westinghouse had produced a generator which operated at 133 Hz. When Nikolai Tesla joined the engineering team working on motors, he argued that this was too high and should be 60 Hz instead. Some believe Tesla based this on the same "magic number" ideas that cause circles to have 360 degrees for example. The important point is that Tesla was arguing for a lower frequency and had enough prestige to do that. When it became obvious that 133 Hz was not practical, principally due to the magnetic cores available at that time, it became impossible to ignore Tesla's arguments for 60 Hz. Had Tesla not been there and had he not been forcibly arguing for 60 Hz, another frequency might have been chosen, perhaps 50 Hz since that would have been twice the 25 Hz that George Westinghouse and several of his engineers should have been familiar with from their work at Union Switch and Signal. But, the team tried 60 Hz, found it suitable, and made it the standard.

The Voltage of 110/115/118/120 is a slight variant on the base Voltage of 100 Volts. That base Voltage was dictated by incandescent lamp development and was largely driven by Ohm's Law and the filament materials available at that time. By way of illustration, a 100 Watt lamp at 100 Volts requires 1 Ampere and a filament of 100 Ohms. A 100 Ohm filament can be quite thin and easily supported. To make a 100 Watt lamp at 50 Volts would have required 2 Amperes with a resistance of 25 Ohms, requiring a filament four times heavier. It is not clear from the historical records whether early engineers considered surface emission area in this matter.