Different Standard Power Supply

[Electroenthusiast]

Why Do Different countries have Different Standard Power Supplies?
like in US 120V/ 60Hz
In India 240V/50Hz
so...on

 

[Electroenthusiast]

Anyone with Answer?

 

[Techie7]

They started like that. So moving on with that.

Is it changeable? No.

 

[Electronworks]

I heard the US moved to 120V cos the electric chair was more efficient at that voltage.


Having played with off line switched modes, I can safely say that 240V works pretty damn good too...

 

[Electroenthusiast]

what does ' off line switched' mean? I still get the required answer frenz

 

[Nigel Goodwin]

I heard the US moved to 120V cos the electric chair was more efficient at that voltage.

Unlikely, as it doesn't work off 120V

 

[Electronworks]

'Off line' switched mode power supplies are switching regulators that work directly from the mains.

Nigel: what voltage do they run off...? Excuse my ignorance in issues of murder...

 

[audioguru]

I don't know if the electric chair is still used. The first few of them used 2000VAC at 10A and frequently caused the victim to catch on fire.
What a way to go.

 

[Electroenthusiast]

oh ok!....anyone with more accurate answer??
thread moving out of topic!

 

[Warpspeed]

Because, in the very beginning, electricity was new, and there were no standards to go by.

Every country just built it's first small power station using whatever equipment was available, and everyone had a different idea about voltage and frequency.

But once you have decided on a voltage and frequency, and you build more and bigger power stations, and start linking them together, the system grows. By that time it is not really possible to change anything.

A bit like building your very first railway. You decide on how far apart your tracks are going to be. Once you have a few hundred miles of track, and a few locomotives and rolling stock, you cannot really then decide to change the width of the tracks !!!

So countries started out (maybe over a hundred years ago) with different rail and electric power distribution systems, and cannot really ever change.

 

[audioguru]

Electricity standards changed. We had 25Hz a long time ago. Then when they changed it to 60Hz every motor and transformer were changed to match.

Trains too had a different space between their wheels a long time ago and when the track spacing was changed the old trains didn't fit.

 

[Electroenthusiast]

y is it AC? y not DC? does the same reason holds good for this?

 

[Nigel Goodwin]

y is it AC? y not DC? does the same reason holds good for this?

You shouldn't need to ask this - AC works through transformers, DC doesn't.

As mentioned previously, there have been various supply voltages, frequencies, and even DC used over the years. But eventually it's settled down to (mainly) 220/240V 50Hz or 110/120V 60Hz.

Until relatively recent times even in the UK there were a few small spots of different mains, not far from me the Staveley Works generated their own power, and fed parts of the surrounding town - this was using 30Hz 240V.

 

[Electroenthusiast]

Thanks...
But i heard that even DC is used as Power Supply (Domestic)!
Transformer doesnt work with DC rite?!!!

 

[RCinFLA]

Trains too had a different space between their wheels a long time ago and when the track spacing was changed the old trains didn't fit.

Did you know the space shuttle's solid booster diameter was determined so it will fit on a railroad trailer.

The width of the railroad tracks (rail gauge) can be traced back to England and the first railroad tracked laid in the trails long established, back to Roman rule days where the width of the trail was created by two horse chariots.

So the moral of the story is the space shuttle solid booster design is based on two horses' ass.

 

[georgetwo]

power suply is different based on these reasons;
Some countries, followed their colonial masters blindly, that is why we have British Standard, America Standard, etc. One other is pride; these countries only want to produce their own electronics to generate more money and increase their technology. America wants to tell the world that they can minimise energy perfectly and they dont need high voltage to run the country and it is true. electrical power is not a question of number but it is a question of consistency

 

[Sydney]

AC is preferable over DC due to the IR drop along transmition lines. For long lines very high voltage -low current, transformed at destinatio to operating voltage. Difference in AC voltage and frequency purely due to local developement.
Sydney

Look outside the square then square it

 

[rmn_tech]

The first UK mains was DC and even in the 1950's domestic equipment was designed to work on AC or DC. The first Railways in the UK were wide gauge before the rail companies got together and standardised the size even in the 1940's we had two gauges and for many years passengers had to change trains to move from one system to the other however both mains and the railways eventually got together and decided on a standardised Idea. P.S. Most electric trains around the world still use DC

 

[mneary]

AC is preferable over DC due to the IR drop along transmition lines. For long lines very high voltage -low current, transformed at destinatio to operating voltage. Difference in AC voltage and frequency purely due to local developement.
Sydney

Accurate but incomplete.

In long transmission lines, high voltages can transmit power with lower losses because the current for any given amount of power is lower. Since transformers have historically been the easiest way to convert from high voltage to low voltage, Alternating Current was chosen.

Because of a phenomenon called "skin effect" which limits the useful cross section of wires carrying AC, DC actually would be more efficient on long distance wires. Until recently the problem has been the conversion from AC to DC and back. In recent years, very long transmission lines (>750km) have been using Direct Current (ref: "DC Intertie").

 

[vsmGuy]

Tesla woudl be rolling in his grave.

It was exactly this problem of transmitting power via long distances for which he invented the Tesla coil model of long distance power transmission that is not used any more.