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Posted by Don Foreman on April 27, 2008, 1:16 am
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On Sat, 26 Apr 2008 21:48:45 -0500, "Martin H. Eastburn"
>Phone companies used to use copper clad steel on poles.
>
>Maybe there is some still hanging or some in the phone yard sitting.
>
>I'd talk to them if the phone or power company has scrap line for
>this type of use. Might find so. Might find a few to help string
>some of which they provide.
>
>Even a bundle of twisted wire could be used - sets of lines in parallel.
>
>The zinc might not be considered in the estimates either. But it leaches off.
>
>
>I think myself I'd send AC - 36V at 1/3 the current and voltage drop. Then
>on top convert that into the 12V. I'd limit to 36 for safety. You might
>have to post flags warning of voltage present. Much like cattle fences.
>
>Martin
That'd work ... but I don't think minimizing voltage drop or
maximizing efficiency is the objective. The objective is to get 12
volts at 0.5 amp at the top of the hill. Ya just need enough push
at the bottom to overcome 4 volts or so of drop in the wire that's
already in place. A regulator at the top takes care of having a bit
more push than necessary, which makes scrounging parts much easier.
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Posted by cavelamb himself on April 26, 2008, 2:44 am
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grumpyoldhori wrote:
> Could I have some advice please.
> I need to get a twelve volt, 1/2 amp supply five
> hundred metres up a hill.
> I do have a fence a metre high made from wooden posts and
> seven runs of Num eight (4 mil) galvanised steel
> wire.
> Is it feasible to use two of these wires to carry twelve
> volts that distance ?
> Thank you.
>
>
No.
Line losses will reduce the voltage at the far end way too low
to use.
That's why we use AC voltage for distribution.
Richard
--
(remove the X to email)
Now just why the HELL do I have to press 1 for English?
John Wayne
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Posted by Karl Townsend on April 26, 2008, 7:29 am
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> Line losses will reduce the voltage at the far end way too low
> to use.
>
> That's why we use AC voltage for distribution.
Thomas Edison never did agree with you on this issue.
Karl
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Posted by cavelamb himself on April 26, 2008, 7:37 am
Please log in for more thread options Karl Townsend wrote:
>>Line losses will reduce the voltage at the far end way too low
>>to use.
>>
>>That's why we use AC voltage for distribution.
>
>
> Thomas Edison never did agree with you on this issue.
>
> Karl
>
>
YEAHbut - his didn't win.
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Posted by Spehro Pefhany on April 26, 2008, 8:01 am
Please log in for more thread options On Sat, 26 Apr 2008 06:29:29 -0500, the renowned "Karl Townsend"
>
>> Line losses will reduce the voltage at the far end way too low
>> to use.
>>
>> That's why we use AC voltage for distribution.
>
>Thomas Edison never did agree with you on this issue.
>
>Karl
>
Yup, and HV DC transmission has advantages over AC transmission, and
can contribute to overall system stability.
http://en.wikipedia.org/wiki/HVDC
250km undersea (Sweden to Germany) 450kVDC cable:
http://library.abb.com/GLOBAL/SCOT/SCOT245.NSF/VerityDisplay/A74338323CD88E19C1256E36003FFD7A/$File/Project%20Baltic%20Cable%20450%20kV%20MIND%20subm-.pdf
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
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>
>Maybe there is some still hanging or some in the phone yard sitting.
>
>I'd talk to them if the phone or power company has scrap line for
>this type of use. Might find so. Might find a few to help string
>some of which they provide.
>
>Even a bundle of twisted wire could be used - sets of lines in parallel.
>
>The zinc might not be considered in the estimates either. But it leaches off.
>
>
>I think myself I'd send AC - 36V at 1/3 the current and voltage drop. Then
>on top convert that into the 12V. I'd limit to 36 for safety. You might
>have to post flags warning of voltage present. Much like cattle fences.
>
>Martin