Re: [OT] British vs. American English
On Thu, 6 Oct 2011 19:07:43 +0000 (UTC)
Virgo Pärna <virgo.parna@mail.ee> wrote:
> On Fri, 7 Oct 2011 02:12:53 +1300, Chris Bannister <mockingbird@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.
--
Best wishes / 73
e-mail: richard@g8jvm.com
Richard Bown
nil carborundum a illegitemis
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