On Thu, 2011-10-06 at 20:33 +0100, Richard wrote: > On Thu, 6 Oct 2011 19:07:43 +0000 (UTC) > Virgo Pärna <virgo.pa...@mail.ee> wrote: > > > On Fri, 7 Oct 2011 02:12:53 +1300, Chris Bannister > > <mockingb...@earthlight.co.nz> wrote: > > > > > > Not sure I understand what you are saying. Unless the wrong terms are > > > being used, but transformers "hate" DC. Plus also, think of voltage like > > > > > > > I ment the voltage drop on the long lines. And that there was no device > > like > > transformer for DC. Thanks the existance of transformers AC could be easily > > converted > > to higher and lower voltages - shich ment, that long distance transmissions > > could be at > > high voltage and converted to lower voltage near the consumer. And that was > > one of > > the main reasons, why AC one out. > > Nowadays DC current is actualy used for long distance high voltage > > power transmissions > > (because of lower losses). But it's my understanding that the voltage > > conversion is still > > not as easy and simple, as it is with AC. > > > > Very simple, if you switch a DC voltage on and off repeatedly, what wave form > do you get ? > If the period of switching it on is shorter that the off period the > equivalent output voltage is > proportional the the width of the pulse chain, ie pulse width modulation. > And a much higher efficiency voltage and mode conversion. A much simpler > process and less lossy. > Only recently possible with high voltage high current due to developments in > semiconductor power > handling.
That reminds me to switching power supplies. Again, I'm an audio engineer. Perhaps those switching power supplies are more efficient, but they cause troubles to the grid. A switching power supplies starts with changing AC to DC, at the end it will cause AC, however, their result are troubles to the grid. I haven't any knowledge about power lines, but I suspect that this high power transformation might be comparable with a switching power supply. How expend effort is needed to clean DC voltage transformed power from troubles? -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/1317955045.9616.31.camel@debian
