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#137849 - 08/02/03 08:16 PM 120 V; 60 Hz vs. 240 V; 50 Hz
JohnS Offline
Member

Registered: 07/31/03
Posts: 36
Loc: Cleveland, Ohio USA
The US, Canada, part of Japan, Taiwan, Cetral America and a few other countries here and there use 110~120 V; 60 Hz as their standard single phase voltage. The 3 phase industrial voltage is 440~480 V. Canada also uses 550~600 V for industries

The rest of the world use 220~240 V; 50 Hz for single phase voltage and 380~415 V for industry.

What is the history of this difference? What is the advantage/disadvantage of one over the other?

What about sockets and plugs? What are the advantages/disadvantages of round pin vs. flatpin?

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#137850 - 08/02/03 09:09 PM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
A few hits…
http://www.electrical-contractor.net/ubb/Forum1/HTML/002075.html
http://www.ieee.org/organizations/history_center/faqs.html
http://www.eng-tips.com type thread238-3663 in the search area




[This message has been edited by Bjarney (edited 08-03-2003).]

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#137851 - 08/03/03 06:17 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
With travel as it is today, it would certainly be convenient if the whole world had adopted a single plug style and a single voltage/frequency standard. Unfortunately. we'd be back to the question of standardization we've been discussing in the cable thread and the problem of who would change.

Europe in general uses 220/380 (or 230/400V) power now, but in many countries they had 127/220V three-phase systems. I think our Belgian friend will confirm that there might be one or two places there which still have such a system, although with only 220V phase-to-phase loads these days.

Britain had 120/240V (or thereabouts) 3-wire DC systems in the very early days (e.g. late 19th century, earyl 20th), but most of these were upgraded to the 200/400 to 250/500V systems which survived in some older town areas until the early 1960s.

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#137852 - 08/03/03 06:23 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
ECN Member C-H has a nice web site that shows the voltages and plug types for many countries.
http://electricity.does.it/
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts

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#137853 - 08/03/03 07:42 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
Not sure about consumer appliances in general, but the IEC320 C13/14 connectors {like on the other end of electronic-equipment power cords} and ~90-260V switchmode power supplies have been a significant advance in 'world power.'

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#137854 - 08/03/03 09:20 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
230V 50hz as used in Europe has a few advantages.

1) Any modern outlet (13amps(UK)-16amps(Europe)) can easily and safely supply at least 3000W making it ideal for portable heating, electric kettles, esspresso machines, irons, high powered vacuum cleaners, washing machines, dryers etc etc.

Many EU countries go one step further and hook cooking and heating appliences up to 380V 3-phase.
Homes may also be supplied with 3-phase with different circuits taking 1 phase + neutral (220V) to balance the load.

2) Because of the higher voltage cabling doesn't need to be quite as heavy.

3) distribution networks are not quite as transformer laden as they are in the US. Local distribution in urban areas can be done at the 220/380V supply voltage distributing power to an entire block / street from a single large transformer (substation).

Rural distribution is, at least here, similar to the US though (i.e. dependent on lots of local pole top transformers)

The US system has the advantage of using lower voltage (110-120V) which is, arguably, slightly safer. With the option of using 240V for heavy appliences, like dryers, as it's a 3 wire system.

However, both 110 & 220V will do a very nice job of killing you. (Bare in mind that early electric chairs operated at 110V!!! albeit DC) It all depends on how much current passes through, where it goes en route and for how long.

Modern RCD (Residual Current Devices) and equivilants in the US have made the chances of surviving a shock from either system much better.

As for the 50 or 60 Hz question:

The US settled on 60 Hz.. Fits nicely into the system of seconds, mins, hours.. 1/60th of a second = 1 cycle.

The Europeans went for an almost metric frequency basically.

The current oscillates 100 times per second (completing a full cycle 50 times per second)

giving you a frequency of 50Hz.

Nice round number.

It amazes me that the entire European area managed to pick 50Hz.. Imagine if every country had gone for a different frequency!!

However, there is really no advantage to either 50 or 60Hz they're just 2 standard frequencies adopted as conventions.

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#137855 - 08/03/03 02:28 PM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
Belgian Offline
Member

Registered: 10/10/02
Posts: 177
Loc: antwerp
 Quote:

I think our Belgian friend will confirm that there might be one or two places there which still have such a system, although with only 220V phase-to-phase loads these days.


Yes, Confirmed. It's even worse than that. I have heard of new building or even whole streets which still can only get from the PoCo 3x230V !

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#137856 - 08/04/03 02:21 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Belgian,
Presumably all houses wired this way use the TT earthing system?

On the 50 vs. 60Hz question, there is a minor advantage in that with 60Hz the transformers can be a little lighter for any given loading. 50Hz was used in some parts of America in the past. Bjarney posted a link some time ago to an article about the 1930s conversion of the Los Angeles area from 50 to 60Hz. Can you remember that link, Scott?

 Quote:
However, both 110 & 220V will do a very nice job of killing you. (Bare in mind that early electric chairs operated at 110V!!! albeit DC)

True, 110 and 220V can both be deadly, but the first electric chair used a lot more than 110V and most certainly wasn't DC.

I've seen values of around 1500 to 1700V quoted for the first use of the chair in 1890. Thomas Edison played a large part in getting the State of New York to adopt the chair, and he was firmly of the opinion that DC was far safer than AC (how much his belief was colored by rivalry with George Westinghouse is very much open to debate).

Some people have gone so far as to suggest that Edison's insistence on the use of AC for electrocution was an attempt to create a distrust of AC in the minds of the public ("Look, they're using AC to execute criminals, so it can't be safe to have in our home.")

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#137857 - 08/04/03 10:54 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
The article is Crookshank, C., Kinsler, M., 1936 Los Angeles Synchronous Clock Project [History] IEEE Power Engineering Review, Jun 1997, Volume: 17, Issue: 6, ISSN: 0272-1724

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#137858 - 08/04/03 11:28 AM Re: 120 V; 60 Hz vs. 240 V; 50 Hz
JohnS Offline
Member

Registered: 07/31/03
Posts: 36
Loc: Cleveland, Ohio USA
I remember learning that originally all the electric power produced in the US was DC. Thomas Edison was actually a proponent of DC. It was said he did not know how to do the math for AC. It was a German immigrant who pioneered AC and the invention of the 3 phase AC motor helped cement the use of AC over DC.

The first use of AC in the US was at 25 Hz. I guess the generators in those days were not efficient enough to produce 50 Hz voltage. 50 Hz was not chosen because of metric, but because it was twice 25 Hz, and machines that ran at 25 Hz could be easily upgraded to run at 50 Hz.

It was an American clock maker who is responsible for the 60 Hz standard. He could sell his clocks more cheaply if he could synchonise them to the line frequency and if the line frequency was stable and of course if the line frequency was 60 Hz. He gave the presidents of various power compnaies gifts of clocks and in order for them to work or keep proper time, the power companies had to insure the frequency was right and stable. This is what established 60 Hz in the US.

What it all boils down to, was the US settled for convenience and the rest of the world for economy. Resources were in abundance in the US 100 years ago and so conserving was not an issue. Now, it may be, but the standards are established and it would cost a fortune to change them.

Those countries that the US played a major role in electrifying use the same power standards as the US. European colonies tend to follow European voltage standards. Korea is the only large scale industrial country I know of that switched from 120 V single phase to 240 V, using the schucko plug and German socket. But, they still use 60 Hz.

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