Question for the UK folks about AC power

[Phonesrfun]

I went to an antique store today about 80 miles from home and bought a Kellogg 900.  You can see that phone in the thread in the collectors corner.

Anyway, while there, I saw on his table a genuine synchroscope!  The dial was about the diameter of a 45 RPM record (Anyone remember those?) and it was about 4 inches thick, with threaded connecting bolts coming out the back.

The proprietor said that it was removed from the powerhouse of a small hydro-electric dam in NE Oregon.  Whaddaya know!

[benhutcherson]

This has definitely been an interesting thread, and here's an interesting side note about US power quirks:

Up in the Northeast Corridor, Amtrak trains actually run on 25 hz. Back in the late '70s, there was a big push to convert everything over to 60 hz-in fact, that was one factor in retiring the GG-1s, which dated to the 1940s and were in service up through the early '80s. The GG-1s could only run on 25 hz. The plans to change everything around never materialized.

[McHeath]

The plans to change everything around never materialized.

Sort of like the plans to convert the US to the metric system in the late 70's. 

[Stephen Furley]

I believe that the section that I've travelled on quite a few times, between Newark and Trenton, NJ, is 11 kV, 25 Hz.  At least that's what the driver that I asked told me.

I believe that there was a narrowly-rejected proposal to convert the US to the metric system sometime soon after the Civil War.  You didn't do yourselves any favours; it really does make life much easier.

I'm on the coach from Oxford back to London, and the on-board Wi-Fi isn't working.  I can't get a 3G connection on my own device either, so it's a very slow GPRS one.

[McHeath]

In the late 70's we started seeing metric figures on everything from gas pumps to highway distance signs.  Speedometers were required to have the metric speeds as well, which they still do.  For years we had this weird deal where cars would have some nuts and bolts in standard and some in metric, but now they are all metric. 

[Dennis Markham]

I recall as far back as the third grade teachers telling us we may as well get used to the metric system because we were going to have to know it.  That was a looooooooonnnnnnnngggggg time ago.  Other than having both measurements on bottles of liquids the practical use of the metric system here has gone by the wayside.  I do recall seeing metric numbers on freeway signs.  In fact only in one area that I can recall and that was in Ohio when the mileage signs showed both miles kilometers for distances from Toledo to Dayton and Cincinnati on Interstate 75.  Stephen it may be easier for you but since the U.S. system is all we've used since birth, this way is easier for me!   It's hard to teach an old dog new tricks.

[contraste]

We still use Miles Per Hour on our speed limit signs in the UK and things like TV screens are still measured in inches.

[HobieSport]

I'm just guessing why America didn't convert to metric during the 1970s because it would mean complete re-tooling. Besides the fact that architecture based on twelve inches is a really good form of measurement in feet and inches; and more dividable than the number ten.

http://www.youtube.com/watch?v=z302bHUMokA

[Stephen Furley]

We still use Miles Per Hour on our speed limit signs in the UK and things like TV screens are still measured in inches.

Milk is in pints if it's in bottles, but litres if it's in cartons.  Draught beer is sold in pints, but bottled or canned is metric.  Arc lamp carbons, if you can still find them anywhere, are odd; they've been metric diameter x Imperial length for as long as anybody can remember.  There are a few exceptions, but not many now.

Yes, the changeover is the worst part of it, and we dragged it out for well over thirty years, rather than getting it over with.

I'm old enough to remember the days when almost everything was in Imperial units; metric was mainly used for scientific purposes.  When I went to school I learned all of the strange units, and awkward calculations between them, and then at about the time that I moved up to secondary school, late '60s, metric started to come in, though it wasn't used much in everyday life to start with, so I had to use both systems for many years.  Now I can just about forget about Imperial units, thank goodness.

It's rather like learning a language; it's really difficult if you're constantly trying to convert backwards and forwards between the two, but once you start to think in the new system it's much easier.

Something interesting about the 120/240V thing.  Some years ago, I think it was in either the '70s or '80s, somebody did some research into the number of deaths caused by the 120V system in the US, and the 240V one somewhere else; I can't remember where.  I can't find the details at the moment, but they are on the Internet somewhere.  What they found was that the number of deaths, per million of the population was considerably higher with 120V; I think it was about twice as high.

This was surprising; I would have predicted that there would be little difference either way.  I don't think there as any conclusive evidence as to the reason, but a number of suggestions were put forward by various people.  These included:

"People perceive the higher Voltage to be more dangerous, so they take greater care with it."

Possibly part of the cause.

"Americans have more appliances than people elsewhere, and therefore more opportunity to kill themselves with them."

I doubt it by the time this study was made, though possibly true earlier.

"With the higher Voltage the normal current will be half what it would be with 120V, but the fault current will be twice as great, so the ratio between the two will be four times greater with 240V, so protective devices will operate faster."

Sounds plausible; I think it would make a greater difference with fuses than with breakers.

"The lower Voltage requires a higher current, which is more likely to cause fires".  (The figures included deaths by electrical fires as well as those by electrocution.)

Again, sounds plausible.

"Americans are stupid, so they do stupid things with electricity."

I doubt it.  America certainly has its share of stupid people, but so do other places.

"American electrical fittings are of poorer quality than those in 240V countries."

True to some extent I think.  We used to have some pretty dangerous fittings here, but tighter safety regulations have removed most of them in the last few decades.  I've seen some pretty horrible things still on sale in America which certainly wouldn't be allowed here.  It seems quite common over there to find plugs running warm, whereas that would certainly be seen as a sign of a fault here.

"The higher Voltage is more painful so you let go of it quicker/it throws you away from it quicker."

I'm not sure about this one; sounds unlikely.

I think that was about all of the suggestions offered.

[Phonesrfun]

I think we should have stuck to the plan of converting here in the US, personally.

What has happened is we have turned into a country of importing many of our items that wind up all being assembled with metric parts any way, and now we have to deal with both.

Cars, for instance now have an interesting mix of both metric and "standard".  Lately, cars have become too complex for me to do much maintenance on, but I used to do things like replacing clutches, transmissions and so forth on my own cars.  I am what you call a backyard mechanic.  As a result, I now have to have two sets of socket wrenches in my toolbox.  Metric tools are not very hard to get used to, and just as in the case of "standard", you can take one look at a bolt head and know which socket to reach for.  It really is not confusing to me.

Where I find it confusing is in trying to mentally convert one to the other.  Gallons to Liters, Fahrenheit to Celsius, Miles to Kilometers, etc.  If we just went to the metric system, I would not have as much need to convert, since everything would be metric.

Right now, if I go to Canada, the moment I go across the border things are in Kilometers and my speedometer shows Kilometers per hour, so it is no big deal.  What does get confusing is knowing whether the price of gas is good or bad.  Canadian gas stations have signs just like the US but the price of gas is expressed in Canadian Dollars per liter, and I want to know how that relates to gas I just bought in the US in US Dollars per gallon.  That necessitates a conversion of both currency and measurement.

The medical and scientific areas in the US have long ago gone metric.

I really think we should convert, but I am not holding my breath.

Now having said that, it would not be good for us phone collectors.  In many cases, I have been able to find a screw at the local Ace Hardware store to fit an old US made telephone.  If all those screws go away, we will be screwed.

[HobieSport]

Well said Bill.

I remember learning about the metric system in the U.S. in the late 1960s and the discussions of converting. But my Dad explained that we would then have to completely re-tool all the factories. We weren't loath to try it though, and it wasn't from sticking to tradition that we didn't.

Personally, with my interest in simple small home architecture, I like both systems of measurement, because with the base ten metric system, all you have to do is move the decimal point when calculating how much plywood to get.

But I also like that we kept the system of twelve inches per "the kings" foot, because twelve is a wonderfully dividable number, divisible by 2, 4, 6 and even 8. Whereas the number ten is only divisible by 2 and 5. I work in mathematical proportions a lot in building designs, and I love the number 12.

I'm not sure what my point is here, other than I wish I had twelve fingers, and that if you have ever tried to carry a metric sized piece of plywood up a rickety staircase four floors up into a cheap room in Paris you might agree.

Frankly, I think the Japanese sizes of 3 x 6 feet makes the most sense, because you can think of them in both centimeters and inches, and they are better scaled to be carried by mere mortals. Just speaking in terms of plywood sizes.

[Bill]

It has always been interesting to me that the one segment of the US economy that adopted the metric system immediately and enthusiastically was the wine and liquor industry. The reason, of course, is that US consumers were accustomed to standard size bottles, and could identify each size by eye. These consumer sizes included gallon, half-gallon, quart, fifth, pint, half-pint, and nip. And in each case, a new metric size standard bottle was invented that is about the same size by eyeball, but contained a bit less of the product.

For example, both wine and liquor used to be available in half gallons, and a half gallon is 1983 milliliters. But the new standard size bottle immediately became 1500 ml for wine, and 1750 ml for liquor. Similarly, the quart bottle (946 ml) has been replaced by the standard 750 ml bottle for both wine and liquor, and the fifth (25.6 ounces or 757 ml) was replaced by the 750 or 500 ml bottle. Even the ubiquitous "nip" (2 oz or 59 ml) that you see behind the cash register has been replaced by a more compact 50 ml bottle.

When the bottle size got smaller, do you think the price went down?

Bill

[dsk]

We all know the economical aspect of changes, at least in a short time window.

What would be the voltage and frequency if we should start on today?

I had the interesting job to sit here in Norway and design a machine for use on the Sanfransisco bay bridge project, and i am sure the industrial standards with 480/277V with rough big outlets.... is a great way to do it. And it was not to much problems to design for a foreign system. But it was quite different standards, and rules. 



dsk

[HobieSport]

What would be the voltage and frequency if we should start on today?

Good question!

If we could have any voltage and frequency (hypothetically asking) in electricity, at home and/or in a grid, what would really be the most useful and efficient? For the sake of discussion, let's pretend that we didn't have to "re-tool" all of our electrical appliances. What would really be the most efficient form of generating and distributing electricity in general?

Since I don't know, I'm really asking.

[Stephen Furley]

About the only use where 120V has a positive advantage over 240V is incandescant lighting, and since that is well on it's way to extinction, it's not a good thing to choose a Voltage for.  I think 240 is about right; halving the current brings considerable savings in copper, which is expensive, but does not require aditional insulation; at these Voltages it's physical/mechanical considerations which determine the amount of insulation required rather than electrical ones.  The Voltage phase-phase is about 1.73  time the Voltage phase-neutral, so 240V comes out at 415V phase-phase, and you probably wouldn't want to go much higher than that.  I think there may be a case for also having a much lower Voltage, personally I think I'd choose 24V, fed from a local transformer.

As far as frequency is concerned, I'd go higher than 50 Hz., at least 60, and possibly as high as 75.  Discharge lamps often show flicker at 50 Hz., and going to a higher frequency would also allow higher speeds with a.c. motors, and reduce the weight of motors, generators and transformers.  Going much higher than this would increase transmission losses over long distances.