[Lowfer] Re: Power outages

Wed, 20 Aug 2003 22:23:11 -0400

Alberto, et al...

I found it interesting that you mentioned TV in this discussion of Power
Line standards.

I say that for the following reason:

I once compiled a (rather humorous) report for a defense agency regarding
the history, use and mis-use of standards. In my research I can across the
following story. It might be urban myth but one never knows. I included it
in my report.

Back in the 30's/40's there was a big electronics show in Italy. And RCA
brought it's Television system to the show for a demo. They set up a
transmitter at the convention site and receivers at the local hotels.

Everything worked well except that the pictures "rolled" vertically. The
engineers finally concluded that the local power plant was not at 50 Hz. So
they brought in a television set to the power plant. The operators were
amazed at what they saw but they complained that the picture was not stable.

"Oh!" said the RCA folks. "Here is how you can adjust that!" And they had
the engineer adjust the speed of the generator until the picture was stable.
"Now, if it starts rolling again you just adjust the speed and it fix
itself."

So I was told...   8-)

Mike
wa1ptc

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Alberto di Bene
> Sent: Wednesday, August 20, 2003 7:11 AM
> To: [email protected]
> Subject: [Lowfer] Re: Power outages
>
>
>
> A few months ago I measured with Spectran the 53rd harmonic of the 50Hz
> power
> line here in Italy, over a period of a few minutes (don't remember how
> many).
> You can see a capture of the screen here :
> http://www.qsl.net/i2phd/53x50hzita.jpg
>
> The crossing line going up is a spur, probably caused my daughter
> switching on the TV.
>
> 73  Alberto  I2PHD
>
> >Just to demonstrate grid frequency variation in the greek
> >network (which is also synchronized with Bulgarian,
> >Albanian etc utilities), I uploaded a GIF file which is
> >actual frequency measurements for the period 16 to 20
> >December 2000 (sorry, the date does not show onthe graph
> >after I changed from Office 97 to Office 2000).
> >
> >I uploaded the file to my web site:
> >
> >http://www.qsl.net/sv1xv/pics/grid.gif
> >
> >as QTH.NET does not accept e-mail attachments.
> >
> >I did these measurements for a client who wanted to
> >install a grid-connected 50 kW photovoltaic generator
> >and had to pass this info to the manufacturer of the
> >DC/AC inverters.
> >
> >It is possible that in other parts of the world the
> >frequency is regulated better!
> >
> >Costas SV1XV
> >
> >
> >
>
>
>
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