Why Do Countries Use Different Power Supplies?

The type of electricity delivered to homes and businesses was first direct current (DC) but then changed to AC electricity. The standard voltage level started at 110V, went to 240V, back to 110V, and then to 220V. The frequency started at 60Hz and then went to 50Hz in most areas.

Early in the history or electricity, Thomas Edison's General Electric company was distributing DC electricity at 110 volts in the United States. Then Nikola Tesla the devised a system of three-phase AC electricity at 240 volts. Three-phase meant that three alternating currents slightly out of phase were combined in order to even out the great variations in voltage occurring in AC electricity. He had calculated that 60 cycles per second or 60Hz was the most effective frequency. Tesla later compromised to reduce the voltage to 110 volts for safety reasons.

With the backing of the Westinghouse Company, Tesla's AC system became the standard in the United States. Meanwhile, the German company AEG started generating electricity and became a virtual monopoly in Europe. They decided to use 50Hz instead of 60Hz to better fit their metric standards, but they kept the voltage at 110V.

Unfortunately, 50Hz AC has greater losses and is not as efficient as 60HZ. Due to the slower speed 50Hz electrical generators are Apx 20% less effective than 60Hz generators. Electrical transmission at 50Hz is about 10-15% less efficient. 50Hz transformers require larger windings and 50Hz electric motors are less efficient than those meant to run at 60Hz. They are more costly to make to handle the electrical losses and the extra heat generated at the lower frequency.

Europe stayed at 110V AC until the 1950s, just after World War II. They then switched over to 220V for better efficiency in electrical transmission. Great Britain not only switched to 220V, but they also changed from 60Hz to 50Hz to follow the European lead. Since many people did not yet have electrical appliances in Europe after the war, the change-over was not that expensive for them.

The United States also considered converting to 220V for home use but felt it would be too costly, due to all the 110V electrical appliances people had. A compromise was made in the U.S. in that 220V would come into the house where it would be split to 110V to power most appliances. Certain household appliances such as the electric stove and electric clothes dryer would be powered at 220V.

plus the yanks always like to be different!!

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Thank you and good night

Trivia and History

Most early AC machines were 25 cycle. The lower speeds were easier to obtain from reciprocating steam engines and water wheels. Of course the machines and transformer were also much larger because of the need for more iron in the cores.

The first 28 machines at Niagara Falls were 25 cycle and they were still in service until the Scholkoff disaster (around 1950) when the river bank caved into the gorge on top of the generators. Two operators bodies are still buried in the rubble.

They later, reinforced 25 cycle machine rotors and turned them at double speed and made 50 cycles, however, Electric Clocks have 60 seconds to the minute and 60 minutes to the hour. The later higher 60Hz frequency made machine design simpler and more economical. Aircraft and servo systems use 400 and 800 cycle equipment to reduce weight and improve efficiency.

Europe when through a similar history.

Authority of information.... I was born in the US in 1927 and I was there!!

When I worked in Broken Hill it was not connected to the Eastern Australian Grid and still had its old diesel generators which ran the mines at 40 Hz 240/415 volts. (The system had been bought in the late 1930s from AEI in the UK - which had its own 40Hz power station.) The large motors in the mines were custom built so there was no problem but the smaller motors were commercial 50Hz motors run via transformers to reduce the hysteresis losses in the iron.

The Western Australia grid was run at 50Hz but at a nominal 250 volts. This voltage has recently been reduced to 240 volts to bring it into line with the rest of the country.

Parts of Sydney's CBD have only recently (about 20 years ago) been disconnected from a 200V DC supply. This was a legacy of the early days of electrification and the DC supply was kept available mainly to drive lifts - 240/415 VAC was used for almost all other purposes in the buildings

Why? Originally all the systems were independent and there was little incentive to have standards. We also have a three pin domestic plug which is different from that of most of the rest of the world (New Zealand has the same one).

Greg

This has been one of the most informative discussions I have encountered in the CR4 system. My US history is rather extensive because both my parents and I grew up in the power industry fields, however, I have little or no knowledge of development in countries abroad. I have heard that some UK systems operate in ungrounded (un-earthed) configurations and system protection is an entirely different science. This is straying away from the original question.

More Trivia.. In the late 1920's my father was the power company in a small town. He and the neighbors built and maintained the power distribution lines and my mother drove the Model T ford around and read the electric meters. The town clerk sent out the bills and collected the money. The source of 25 cycle power was from from a Niagara Falls power company 60 miles to the West. The Niagara transmission voltage was 66 KV and the local purchase voltage (to the local power company) was 4160 volts. A typical farm load was a single light in the house kitchen, a milking machine in the barn and a 1/4 horse motor on a pump jack (water pump). Monthly bills of over a dollar and a half were often seriously contested. The original village system had about 350 customers.

How would you possibly find out this stuff if you had not known anyone who lived it? Great thread.

Nice, informative post!

Snakemike,

What you are saying is that the USA has been keeping green house gas production down all these years whereas Europe continues to generate more by not converting to the most efficient approach?

David

Hi

I tought Britain is 240 Volts system.

Kimi

USA

Hi Snakemike,

Your researched were corrects. But you've left out one important subject is that every coal, hydro-electric power, nuclear power plants are following per basic idea for generates electricity, which is electromagnetic induction or mechanical energy convert to electrical energy. Therefore, AC source, when a rotating a coil in a magnetic field generate the power (emf) in ONE complete revolution or cycle per second that is 1Hz, also, 60-cycles per second (60Hz).

Based on some comment, said "why you cannot use it on the other frequency or higher even better?" in order to answer to Andy Germany's question is No! Because the winding in the transformer impact its performance, direct relationship is the loading impedance or Xl=2*pi*freq*L. or, how cool of equipment that you wanted to operate. Lower the frequency generates higher current and hotter to operates

For the safe practices in the realm of the mechanical ability to operate efficiently within 3000-3600 RPM or 50-60Hz (50-60 cycles per second), deliver huge power through the high voltage line, distance miles lesser lost. If you're talk about 400Hz and 800Hz are the realm of military's specification which is another part of discussion.

Europe likes to operate 50 cycles, more current and less voltage (90V ac outlet).

United States likes to operate 60 cycles, slightly lesser current and higher voltage (120V ac outlet) than the 50 cycles does. On 50 cycles was operate about 17% less efficient than 60 cycles does. For those whose travel, when use his/her laptop computer, electric shaver and up to hair dryer. Principle of delivering power still followed the law of physic. Just like the statement above was stated. Global warming is endless process, day by day which we are working toward the better. The 50 cycles was established in the early day and now day different.

Cheer,

Nuphea.

I think you are not understanding the differences in Alternators and Transformer and you comments to Snakemite are invalid.

The only limits to the speed that you can run a generator are tbe mechanical ones, i.e. mechanical forces on the armature etc.

With a given field, a alternator will develop a voltage proportional to its speed and a frequency proportional to its number of poles.

The inphase load currents are basicaly limited by

The size of the wire, the available cooling air, (or hydrogen in large machines),the horsepower input and the connected load are the primary functions that determine the current and heating.

The frequency (within reasonable limits) has no function on the amount of heat

It is a generator, NOT a transformer. The field flux is fixed, the EMF is induced in the rotating coil. not the other was around.

There is a difference because the flux in transformer core is induced into the core by the primary windings and is a function of the voltage. At low frequencies, core saturation can occur and then only the resistive component limits the current. Direct heat from the I ² R losses will occur. The transformer can also be re-rated to a lower voltage and still operate.

And for you experts, I know I have omitted a lot of parameters in this comment, Keep in mind that I am aware of them. Lets not muddy the water for this commenter.

OH OH

My comments were directed to NUPHA and went out by accident while they were in composition.

Boy that is sure messed up wording and spelling..

Hi Snaker,

I did knew, the transformer consist of winding coil and it can only handle somewhat in the current of wire can holds (indeed, the resistance in the wire has uniform cross section area, its formula is Rw= resistivity*(length/cross-sectional area) which is creating the heat created by the primary coil (it definitely the size power transformer). if you're near by high power station, huge power transformer has the fins on them.

Remember! Power IN is equivalent to power OUT (In the transformer).

In my early comment have just stated, replied to the original question.

Yes, I am familiar with those items.

And a technical correction, the power in is equal to the power out PLUS the core loss, which can be significant.

And Resistivity in your equation is a factor, generally expressed in ohm-cm at 25 ⁰ C

I worked as an electrical engineer for 35 years at a power company in New York State utility and I am also a member of IEEE and have co-authored several papers.

I am now retired and 79 years old.

Hi Snakers,

Thanks you very much, pardon for my technical correction is needed. what part I did not that I was not understood? Because I have alot to learn from this post. Please do! maybe I'm thinking ahead to myself without pay attention with the details.

Thanks again.

with you knowledge of these systems you must be aware or the Two Phase systems that were in some cities like Phila PA

Sorry Snakemite, but there us no evidence to suggest that that UK (Great Britain) ever generated and transmitted 110v and certainly not after 1896. The UK first started generating and delivering 250v DC from local power stations in major cities and as demand increased, the standard generating an distribution voltage was fixed at 250v AC. (440v -3 phase).

After the second world war this was formally reduced to 240V and 415v and more recently - 230V and 415v for European harmonisation.

110v AC was only ever derived in the consumers premises using step down transformers either for instrumentation and control, or power tool safety where the transformer was centre tapped to reduce th earth fault voltage to 55v.

I worked in the electricity supply industry since 1970 and never encountered any evidence or history of 110V distribution.

Throughout the 20th century British engineers were responsible for building the supply industry in commonwealth countries such as Australia and India and naturally the British standard distribution voltages followed.

Th introduction of the British 30A Ring Main and 13A fused plug top for domestic installations was conceived by a government sub-committee during the war in 1944 as the rapid development of electrical technology, as a result of war time experiments indicated a substantial increase in domestic energy consumption.

My Father was an electrical engineer and he mentioned the fact that the UK had many different "species" of supply, even DC, up to the end of the 1930s....

As to how widespread it was, I don't have a clue.

I think a good one word answer to all this is "history"!

It is true that the lower frequencies were used when the Prime Movers of the day were often Steam engines and not Turbines......

60HZ is more efficient than 50HZ, 100HZ would be even better.....and technically would be no problem today, were it not for all the older equipment around.

What the absolute best frequency for all concerned would be I personally do not know, but I guess it would be around 1KHz or near.....

110 volts was used as a "safer" voltage, but with the problem that a) it still can kill, it is not "safe", just somewhat "safer".....and a lot would argue that point!

110 volts also has the problem that for the same wattage, all the cables must be twice as thick, more copper, more costs and a lot heavier.....

With modern safety equipment, I see no advantage of 110volts as residual circuit breakers can be installed that once a very small fault current flows, they remove the supply within a few milliseconds or so. It still hurts though!!! I accidently tried it about 10 years ago!!But it should not kill anyone with reasonable health!

Here is an interesting ( and short) article on the origins of the 50 and 60 cycle standards:

http://archives.openflows.org/electronetwork-l/msg00678.html

This has been one of the most interesting threads and and many have given wonderful messages . As has been discussed 110 vols 60 Hz now is considered standard voltage for US and 220/230/240/250 volts 50 HZ is the standard now adopted in European and Asian countries .Why it is so is history. But why it should not be changed for better safety and energy transmission loss is a matter which can be debated. If anybody recommend a change in voltage and frequency what will happen to all the electrical equipments which are presently in use in these countries .In US since transmission to towns and villages are 110 /220 voltage but the transformers are fixed at close proximity to the load un like in Asian countries where long overhead distribution lines are laid at 440/220 volts 50 cycles .If 110 volts distribution is used the transmission there the power loss will be very large and voltage at users premises will be much below the rated voltage .So a distribution system with least transmission loss of power is better.

Considering the acute shortage of power generation in developing countries the transmission loss play a vital role.Hence it is essential that engineers and scientists to carry out research to find a more suitable voltage and frequency level for those countries and if economical a single standard for entire universe. At least it may be benefit the countries where use of electricity is not popular and will grow . But a different standard will also have its disadvantage as the latest equipments and machines made by developed world cannot be used there with out an adapter. Simple example is that I bought a small machine from US and when I took it to India I had to spend almost same cost of the original equipment to buy a 230 50 Hz adapter to use it there. So universal standard is always good for future world but the decision will depend on economical considerations of each country.

HALLDAVIDI

I'm only winding you up i knew someone would bite,

Plus i didn't say it was a bad thing to be different!

Anyway i know your alot better then us, (US being the UK) for green house gases especially on your car CO2 admissions

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Thank you and good night

Great thread guys...very informative recreational learning, Thanks

Where I live in the Berkshire Hills of Western Massachusetts, I've often thought there should be a museum to the history of electric power which is supported by this question and all the marvelous historical information everyone has provided so far.

It was here in Great Barringon, MA (ca. 1886) that Robert Stanley first electrically lighted the downtown area with alternating current using his own generating system and "induction coils" (power transformers). Stanley had been an employee of George Westinghouse in Pittsburgh but returned to the place of his childhood for health reasons and, possibly, for personal business reasons (i.e. he had a better idea to build transformers and Westinghouse might have been stifling him?). Stanley's 'experiment' was a great success and he was persuaded by local financiers to move his business to nearby Pittsfield, MA...and the rest, as they say, is history.

Westinghouse's alternating current (AC) eventually clobbered Edison's direct current (DC) so much so that GE's financial backers told Edison to buy into the AC business and, wouldn't you know, GE bought Stanley's business. Edison seems to get all the credit in the textbooks but in reality he was but one of many (much like Bill Gates, Larry Ellison, Steve Jobs are only a few of many in the modern era of distributed computing) who brought us the AC grid that so many now take for granted.

Interestingly, George Westinghouse and his wife took a fancy to the Berkshires and built a house here. While his primary home in Pittsburgh, PA was replete with all manor of gadgetry and power systems, he built his own coal-fired power plant here and, much to the chagrin of many other local well-heeled citizenry who did not want unsightly power lines, he electrified much of the local area and laid all the wiring underground in lead pipe. The original street lights are still in use.

My daughter interviewed some local IEEE members (retired GE employees, at that) about the power plant (which was demolished about 50 years ago) and we toured the site in search of memorabilia. During that tour much was shared about the haphazard historical growth in power frequency and voltage. As was the case 25 years ago in software, there were many competing options offered and standardization (as others have written in this blog) came about slowly and generally along geopolitical boundaries. It interests me that nearly 125 years later, we still do not have a universal standard!

But, as I learned, changing a patchwork quilt to a common thread is fraught with difficulty. To this day, there are buildings in New York City that still run on Edison's DC. The Brooklyn Naval Shipyard (with it's hay day in the 1940's) and all of lower Manhattan (until the World Trade Center complex was built in the late 1960's) all operated on DC. And, if memory serves me, many aluminum smelting facilities in western portions of North America still run on 50hz AC because they were built with their own power systems before the grid existed.

I'm told that of the aforementioned Westinghouse power plant in Massachusetts that he distributed his alternating current at something like 440 volts and had a transformer vault (sealed room) in each home on his system. And, while the rooms might be sealed, the power lines are still 'hot'. Pity the poor mouse that ventures into such a space!

How do you archive some of these threads? I find some of these to be great reference material and would like to be able to save them without the cut & paste process.

Thanks

Hi Yani,

The best way to maintain contact with a post is to subscribe to the discussion. Just click on the Subscribe menu at the top of the page. This way, you will be informed when others post to this thread and you will have its location saved so that you can return to it easily at a future date.

- Chris

Thanks Chris,

How long do these threads staye active?

It varies. Most stay active for only a few days, but some can truly take on lives of their own.

Since we have digressed from the original thread, can anyone tell me how to import a picture or diagram into the text box. I have managed to copy text from Word, but not Word diagrams or pictures