Edison would've approved. What's the basis for your claim?to be fair DC is the best form of voltage for transmitting (very) high power.
It's the same equation, the only thing that dominates is Ohm's law. Reduce the current flowing through the transmission lines or increase the cross-sectional area of the lines to minimize power losses. A transformer to step up voltage on one end and down on the other costs far less than increasing the wire gauge for long distance power transmission.high voltage is prefered since the cable losses will be dominated by V^2/R instead of I^2*R
thus as far as power is concerned less is lossed in heating the cables
Electronics (which regularly lied to us)
A few statements that shouldn't go unchallenged. Science vs. electronics is a false dichotomy. Electronics is a subset of physics, itself a subset of science. What may appear as "lies" should probably be chalked up to misunderstanding before placing the blame on an abstract entity.So, I am asking who was right, Science or Electronics? I wouldn't be supprised if Electronics was just plain wrong.
ah, no, sorry. By 'Science' I mean the subject that we taught in school. (my into paragraph said it was about stuff during my GCSEs, although non-UK people may not know whatthey are). So when I said 'science taught me blah', i meant that i learnt 'blah' in my science lessons. And my comment that electronics regularly lied to us, meant that our electronics teachers lied to us, rather than the subject lying to us. The reason that I phrased it like I did, was because out teachers only taught us what they had been told to teach us,so it wasn't really them that lied to us, bu the subject that was lying. If that makes any sense.A few statements that shouldn't go unchallenged. Science vs. electronics is a false dichotomy. Electronics is a subset of physics, itself a subset of science. What may appear as "lies" should probably be chalked up to misunderstanding before placing the blame on an abstract entity.
It really makes that much difference? I didn't know that.IF you have a DC shock you will tense up and if it is around a cable you wont let go.
AC has points of zero voltage so it is more pulsing and more chance to pull teh cable out.
grrr_arrghh said:So basically, power (in this instance) is transmitted using AC because that it was is created by the generators, and it is easier to step up AC to high voltages. You also say that what our science teachers taught us was wrong, because DC is more efficient? But you would say that what our electronics treachers taught us about less chance of being seriously electrocuted, is true, but not the reason for power being transmitted as AC?
laroche73 said:Ok, this thread is verging on the ridiculous.
Edison would've approved. What's the basis for your claim?to be fair DC is the best form of voltage for transmitting (very) high power.
which does what? I'm guessing the link is between england and france - and I can't believe the french let us share their power? (no offence intended to any frech people...)there is a high power DC-link connecting Europe to the UK
grrr_arrghh said:which does what? I'm guessing the link is between england and france - and I can't believe the french let us share their power? (no offence intended to any frech people...)there is a high power DC-link connecting Europe to the UK
err, what?we do have the JET
grrr_arrghh said:moving away from the orginal topic i know, but this is quite interesting.
err, what?we do have the JET
"Above a certain break-even distance (about 50 km for submarine cables, and perhaps 600-800 km for overhead cables [3]), the lower cost of the HVDC cable outweighs the cost of the electronics."
HVDC can carry more power per conductor, because for a given power rating the constant voltage in a DC line is lower than the peak voltage in an AC line
Nigel Goodwin said:Generally teachers in schools know next to nothing about Electronics, there may be the odd exception - but it will be rare!. So you need to take anything they tell you with a 'pinch of salt'..
Nigel Goodwin said:AC and DC generators are both pretty well as easy to build, the main advantage of DC is that you more often need DC power than AC power. Using DC mains prevents the requirement for rectifiers in electrical equipment - however, it's far simpler to convert AC to DC, than DC to AC.
AC won, hands down, simply because of it's ease of voltage conversion.
This is only practical with AC, as transformers simply, cheaply, and reliably perform the required conversions.
Believe it or not, the skin depth of copper wire at 60Hz is only 8.5mm, and 9.3mm at 50Hz.laroche73 said:I'm a little doubtful of the "skin effect" argument though, the effect increases with increasing frequency and is pretty much negligible under audio frequencies. Of course, "negligible" could be "significant" at Grid power levels.
The fact that thick cables are used in your car has nothing to do with the fact that it's DC but that your starter motor uses a lot of power at a very low voltage.captainkirksdog said:Did you ever notice how big the battery cable is in your car? It's only about 3 or 4 feet long, but for even that short a distance it has to be that size in order to carry the current required by the starter motor. Can you imagine how big the cables would be if everything were DC? And since nature abhors a vacuum, can you imagine how big the birds that evolved to roost on those cables would be?
Actually DC is safer than AC.Styx said:The comment abt AC being safer is 1/2 true, if you have ever touched a AC line it is ok (still not nice), but DC is, well dont do it. I have been shocked by AC, 230V alot and I am careful but not as worried abt DC I have been shocked by DC once (28V) and never again. In DC systems you tend to have alot of DC-link caps, you short them and you could have thousands of amps flowing through you, it only takes 20mA to your brain/heart to kill you.
IF you have a DC shock you will tense up and if it is around a cable you wont let go.
AC has points of zero voltage so it is more pulsing and more chance to pull teh cable out.
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