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Mr Alan
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Quote: from bkkfella on 10:23 pm on Mar. 16, 2005
Mr Alan said...
"... But there are other types of new electrical "gadgets" that do need the correct Hz..."
Mr Alan.... I am curious what those gadgets might be and why they care about the power frequency ??
I can't think of any reasons why it would matter.
The point I was making is that it is not entirely a question of whether the gadget is new or old.
Electrical gadgets that run on DC power don't really care about Hz, because the transformer (or charger as most people describe it for a camera or PC) does the conversion from AC to DC, and DC does not have a Hz rating like AC. It is easy to build a transformer (charger) that can accept multiple frequencies and voltages.
But there are still some products that do run on straight AC, like variable speed AC motors for power tools, etc, that might depend on the correct Hz to run as designed. Most new stereo equipment specifies 120 volts and 60 Hz for the USA/Canada versions, but I can’t exactly tell you why.
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Thai Girls : Meet Sexy Thai Girls
Posted on: 2:01 am on Mar. 17, 2005
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Mr Alan
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Quote: from Ballsburstin on 12:19 am on Mar. 17, 2005
Always wondered, given that the first real power grids where in America so long ago (Edison Electric, and so on), why is it that the 120 vs 240 volt thing was never standardized world wide to one or the other? Anyone know the history of this?
- Balls
It is hard to change the voltage once the grid is in place and electrical products are manufactured. As you said, the US had the first grid and so their standard is older. 240V is easier to transport, but in the early days in the US there was a real fear about the dangers of AC power.
In fact Edison was originally pushing for DC power, and he conducted public relations campaigns to scare people about the dangers of AC power. But DC is extremely difficult to transport over a grid, and AC won out (championed by Nicola Tesla). But people were still scared about high AC voltages at the beginning, so the 120 volt standard was adopted (actually it was 110 volts in the beginning).
By the time that Europe and the rest of the world got electricity, the public did not fear AC voltages as much as before, and they were able to start off with a more efficient standard (in terms of ease of distribution).
Same thing happened for TV’s. The NTSC standard used in the US is not as good as the PAL standard used in EU and many other places, because the US developed their standard much earlier than other countries.
As time goes on, technology improves, and the later that standards are adopted, usually the better the standard is.
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Bangkok Women : Meet Sensual Bangkok Women
Posted on: 2:17 am on Mar. 17, 2005
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Smegma
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I can tell you why. But not sure what Alan wanted to address.
Posters in the previous page were right when saying that for all your purposes frequency matters mostly for gadgets that use the frequency to measure time. Or to drive motors that have to run at a fixed speed -like an old tape recorder or a turntable. That old digital alarm clock by the side of your bed counts on the frequency being 60Hz exectly in order to wake up you up at the right time. However, frequency is rarely exactly 60.000000 Hertz. It may more likely be 59.980 Hertz for part of the day and 59.960 for some other parts and so on. This would explain why after a week, you may be waking up a couple of minutes later.
A 50 Hertz electrical motor will work fine at 60 Hz, just 20% faster. The other way around, if the engine was made with just the minimum amount of active material (iron and copper) then there may be some issues about heat dissipation. But you shouldn't have to worry about this.
What does matters to you at the end is the effective power output. If you are at the right level your appliance should work work fine. Regardless of frequency being 50 or 60 Hertz -unless as indicated above for the keeping of time or for some old fixed speed motors.
By the way, your regular one phase voltage/current transformer does nothing to frequency. It couldnt care less about it. Frequency goes 1:1 through it.
Variable speed AC motors will run fine at 50 or 60. Only difference you could notice is if compared to previous calibration. In other words, the dial will not give you exactly the same speed at the same setting as before.
For most solid state gadgets, frequency of the power source nowadays is irrelevant as they are internally driven by DC (converted from the grid's AC and brought down to the typical 5 v or whatever voltage the circuit runs on).
Alan, I like seeing you lecture about electrical matters. It gives me an idea of how I would likely come accross if I tried to sound all knowledgeable about US law. Hmmm.... maybe I should give it a try just to see how you would reply to me.
(If I tell you the donkey is black, be warned that I pinched it and have some of its hairs in my hand  )
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Posted on: 2:49 am on Mar. 17, 2005
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Smegma
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Alan, please.... when you say that 240 is easier to transport....  You do not transport 240 or even 120. You transport ENERGY.
And energy is really never "transported" at 240 or even 120 except in the very last few yards prior to final residential consumption. And this is called "distribution." Not transportation. Transportation is made over large distances and at much higher voltages. Actually it is not even called transportation but the most common word used for those that work in this area is "transmission."
Both 230/240 and 110/120 are transported at much higher voltages not due to "ease" but because losses are lower at lower currents (now, we do not want to get started on a discussion on losses over transmission lines). And the higher the voltage, the lower the current for the same amount of energy "transported." Voltage coming out from generating facilities is usually stepped up to a few hundred thousand volts to be transported over long distance lines and then brought down as it is ready to be "distributed". The primary side on the last transformer prior to final distribution for residential purposes is usually around 440 volts in a typical single phase transformer. Thus bringing it down to 120 or 240 for residential use once it has already been "transported" has nothing to do with it being easier to transport at this stage.
Now, however, as said above you are right that in general transporting at higher voltages is more efficient. But talking of transporting at 240 being easier than at 120 does not make much sense once that level already and so close to final consumption.
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Bangkok Girls : Meet Sexy Bangkok Girls
Posted on: 3:08 am on Mar. 17, 2005
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bkkfella
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Smegma
Are you sure about that or are you a bit in doubt ???
Sorry.... couldn't resist that one (See his signature)
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Yes, for a given power level, transmission at higher voltages means lower current and current is the cause for one major component of losses. Distance is the other major component.
Interestingly enough, there has been a fair amount of work done on long distance DC transmission. The rectifiers and inverters needed to make this happen have become cost effective and competitive with AC transmission. It was the low cost of AC transmission which originally won out over Edison's DC proposals and plans. History comes around full circle sometimes.
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Thai Women : Meet Matured Thai Women
Posted on: 5:35 am on Mar. 17, 2005
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dotcom
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Quite right Smegma.
Those massive power lines out by the new airport are the 40Kv lines 40,000 volts, which get stepped down along the way - to the 440 or 480 which runs down your street (3 phase). the lower set of lines are the 240 single phase ones.
Smegma is right to say that the only time hz would be a problem would be an air conditioner or a fridge - built to USA standards & then try to run it overseas on a transformer. The appliance will never cool properly because it will be running at too low a speed. (the compressor motor).
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Posted on: 6:17 am on Mar. 17, 2005
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MarkC
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Quote: from Mr Alan on 2:11 pm on Mar. 17, 2005
Quote: from Ballsburstin on 12:19 am on Mar. 17, 2005
Always wondered, given that the first real power grids where in America so long ago (Edison Electric, and so on), why is it that the 120 vs 240 volt thing was never standardized world wide to one or the other? Anyone know the history of this?
- Balls
It is hard to change the voltage once the grid is in place and electrical products are manufactured. As you said, the US had the first grid and so their standard is older. 240V is easier to transport, but in the early days in the US there was a real fear about the dangers of AC power.
In fact Edison was originally pushing for DC power, and he conducted public relations campaigns to scare people about the dangers of AC power. But DC is extremely difficult to transport over a grid, and AC won out (championed by Nicola Tesla). But people were still scared about high AC voltages at the beginning, so the 120 volt standard was adopted (actually it was 110 volts in the beginning).
By the time that Europe and the rest of the world got electricity, the public did not fear AC voltages as much as before, and they were able to start off with a more efficient standard (in terms of ease of distribution).
Same thing happened for TV’s. The NTSC standard used in the US is not as good as the PAL standard used in EU and many other places, because the US developed their standard much earlier than other countries.
As time goes on, technology improves, and the later that standards are adopted, usually the better the standard is.
What a load of old arse: 'By the time that Europe and the rest of the world got electricity'.
There were DC grids in place before they existed in the US (publicly lighting whole towns as opposed to just a few private residences). These places changed to AC and higher voltages when they realised there was a better (more effecient, less lossy) way of doing things.
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Posted on: 10:17 am on Mar. 17, 2005
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Mr Alan
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Quote: from MarkC on 9:11 am on Mar. 17, 2005
What a load of old arse: 'By the time that Europe and the rest of the world got electricity'.
There were DC grids in place before they existed in the US (publicly lighting whole towns as opposed to just a few private residences). These places changed to AC and higher voltages when they realised there was a better (more effecient, less lossy) way of doing things.
OK, by the time they got AC electricity, there was much less fear of higher AC voltages. AC electricity was deployed (on a wide scale basis) in Europe after the US had deployed it.
Speaking of arse, that probably explains the lack of bidets in the US. Toilets in Asia and Europe (in places where the Europeans and Asians actually have toilets) are more sophisticated and more likely to have bidets.
The later the technology standard is introduced, the more sophisticated the standard is.
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Thai Women : Meet Matured Thai Women
Posted on: 11:21 am on Mar. 17, 2005
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Mr Alan
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Quote: from sanook269 on 10:09 am on Mar. 17, 2005
Most homes in the U.S. today have 220 volts running to the "service box" on the outside of the house. From there 110 is
ran to the "standard" outlets and 220 is used for "heavy applications" such as air conditioning, electrical stoves, cooktops, whatever.
Actually, what they do is double-up 120 lines to get the 240 on the circuit panel.
The standard in the US was changed was 110/220 to 120/240 years ago.
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Posted on: 11:23 am on Mar. 17, 2005
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