Re: History Re: [TCML] Kids class Project

["resonance" <resonance@xxxxxxxxxxxx>]

The real big problem with HV DC lines is that they don't work with 
transformers.  You can use an AC xmfr from the generator and into the 
substation, jack up the voltage with an AC transformer, then rectify it with 
relative ease, and then transmit it at low loss over long distances.  The 
problem occurs when it gets to where it is going.  You can't use a 
transformer on a 750 kV DC line.  AC works fine with xmfrs but not DC, so 
you need a high voltage inverter to bring it back to 60 Hz to operate on the 
local distribution legs and with the AC xmfrs at homes and factories.

Recently, with the advent of IGBTs and other transistorized devices, the 
power industry is coming around to using DC lines in certain applications.

Dr. Resonance




----- Original Message ----- 
From: "Dave Halliday" <dh@xxxxxxxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Wednesday, December 05, 2007 11:52 PM
Subject: RE: History Re: [TCML] Kids class Project


> I was waiting for someone to bring up the scalability of DC electrical
> transmission.
>
> We have quite a few DC long-haul lines in the USA and Canada.
>
> What was implied in my "not being able to scale" comment was "given the
> level of technology available to Tesla or Edison at the time".
>
> Cheers!
> Dave
>
> > -----Original Message-----
> > From: tesla-bounces@xxxxxxxxxx
> > [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Dave Pierson
> > Sent: Wednesday, December 05, 2007 6:41 AM
> > To: Tesla Coil Mailing List
> > Subject: History Re: [TCML] Kids class Project
> >
> > [Not sure how far into history I/we should go...]
> > >    I seem to recall a homopolar motor. It can be built and
> > then a paper
> > >can be written on its operation. Instructions here:
> > http://www.evilmadscientist.com/article.php/HomopolarMotor
> >    Last I looked, Homopolar motor preceded Tesla.
> >    Faraday?
> >
> > >...scalability of DC...
> >    Wellllll.
> >     8)>>
> >
> >    DC can be scaled, some little known exercises in the 20 in Europe.
> >    Modern Solid State technology (done earlier with ignitrons) allows
> >    HVDC links.  One end of one such helps power my area, receiving
> >    +/- 500KVDC and chopping it back to AC.
> >
> >    best
> >     dwp
> > _______________________________________________
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