Cable Long Runs.Experience,Theroy

[Magic Mushroom Farmer]

Hey I need to conduct 12VDC @ 130 AMP over 300-400m with minimal loss
and expense.(we all need to do this right?)
I have discovered that I may need some seriously heavy duty cable for
my power station.

Basics are understood that DC was no good for long runs therefore AC is
used.
7 to 12 miles for DC dose not ring bells!?

Questions:
Is It dumb to try to transport DC over such a distance?
What loss can I expect provided I can find a matching cable specific to
my requirments.?roughly(have been googling,but looking for been there
opinions)

What Cable has been used in the past for this type of
application......at a guess would it be right to assume,phone
cable?telegraph?amps rating? Old hydro cable?That copper cable they
used to run by the train tracks 20 years back?

Do I need to go 24VDC to get back to 12VDC at destination?(hate this
idea)

I can find 100amp cable in 100m rolls where do I look for bigger stuff
?

Finally is it worth AC over this distance?I would gather a similar
infustructure would need to be in place as with DC?

To tidy this up,what cable should I be looking at using?

Thanks in Advance

 

[Phil Allison]

"Magic Mushroom Farmer"

Hey I need to conduct 12VDC @ 130 AMP over 300-400m with minimal loss
and expense.(we all need to do this right?)
I have discovered that I may need some seriously heavy duty cable for
my power station.

** Yep - the cable needs to be about 100mm diameter of stranded copper,
per conductor. That would give you about 1.6 milliohms overall for a 700
metre round trip. Voltage drop = 208 mV @ 130 amps.

Basics are understood that DC was no good for long runs therefore AC is
used.

** Nope.

Is It dumb to try to transport DC over such a distance?

** Nope - DC is best actually.

What Cable has been used in the past for this type of
application....

** Thick cable.

Get the point?

I can find 100amp cable in 100m rolls where do I look for bigger stuff
?

** 100 amp cable is rated for 240 voltsAC.

No good for 12 volts DC.

Finally is it worth AC over this distance?

** Only if it is 240 volts AC.

Then convert down to 12 volts DC

Maybe use a big lead acid battery and a big charger.

To tidy this up,what cable should I be looking at using?

** Very, bloody thick.

Bout 50,000 kilos of copper.




......... Phil

 

[Magic Mushroom Farmer]

Thanks Dave.....thanks for confirming down-conversion as the most
efficent and proven,cheapest way to get this to work.
Have a clear idea of what I am doing now.
Got stuck on the idea that large cable was readily available and was
commonly used.
Not sure if I can find a cheap 24VDC alternator.

 

Snip

The higher the voltage the less copper you need.
130A is a heck of a lot though, you might need multiple DC-DC
converters at each end.

Dave

G'day

thats a huge cable you're cable you going to need, assuming you want a
voltage drop of <10%

AS3008 gives guidance on cable selection, gives both maximum current
carrying capacity and voltage drop and other properties for a large
range of cables in a large range of situations. Get a hold of this if
you want to calculate it properly....

Your cheapest way would be to bump it up to 240VAC at the supply end
and back down to 12V DC at the load end. Inverters and power supplies
would probably cost say around $1000 - $1500 maybe - just an order of
magnitude cost. You could use much smaller cable then and have better
voltage regulation by using the power supply.

To move 130 amps at 12 volts over 300 metres would cost tens of
thousands of dollars, maybe hundreds of thousands. You would need
multiple runs of say 240mm SQ Al cables.... That cable is about $15 a
metre and you would need a stack of them in parallel. You'd be able to
tow an aircraft carrier with the cable

If you step it up to 240VAC you can use standard off the shelf parts to
do it, standard cables, accessories etc. DC at even 240V in any sort of
quantity gets to become a pain to switch and fuse - you need high rated
parts.

Goodluck

Cheers

 

[dmm]

On 23 Mar 2006 01:45:46 -0800, "Magic Mushroom Farmer" <jjbruce@gmail.com> wrote:

Hey I need to conduct 12VDC @ 130 AMP over 300-400m with minimal loss
and expense.(we all need to do this right?)
I have discovered that I may need some seriously heavy duty cable for
my power station.

Basics are understood that DC was no good for long runs therefore AC is
used.
7 to 12 miles for DC dose not ring bells!?

Questions:
Is It dumb to try to transport DC over such a distance?
What loss can I expect provided I can find a matching cable specific to
my requirments.?roughly(have been googling,but looking for been there
opinions)

What Cable has been used in the past for this type of
application......at a guess would it be right to assume,phone
cable?telegraph?amps rating? Old hydro cable?That copper cable they
used to run by the train tracks 20 years back?

Do I need to go 24VDC to get back to 12VDC at destination?(hate this
idea)

I can find 100amp cable in 100m rolls where do I look for bigger stuff
?

Finally is it worth AC over this distance?I would gather a similar
infustructure would need to be in place as with DC?

To tidy this up,what cable should I be looking at using?

Thanks in Advance

I'm curious.

What's your application? What sort of load requires 12 volts at up to 130 amps?
Why can't you have your load closer than 400 metres to your source?

David

 

[The Real Andy]

On 23 Mar 2006 03:40:13 -0800, "Magic Mushroom Farmer"
<jjbruce@gmail.com> wrote:

Thanks Dave.....thanks for confirming down-conversion as the most
efficent and proven,cheapest way to get this to work.
Have a clear idea of what I am doing now.
Got stuck on the idea that large cable was readily available and was
commonly used.
Not sure if I can find a cheap 24VDC alternator.

I am thinking welding cables - perhaps you can get these in the size
you want.

 

[Pete]

dmm wrote:

What's your application? What sort of load requires
12 volts at up to 130 amps?

I think the OP kind of implied that it was a micro hydro system.

Why can't you have your load closer than 400 metres to your source?

If I drew the right conclusion above, then I guess because the river is
400 metres from his house

Peter

 

[Terry Collins]

The Real Andy wrote:

I am thinking welding cables - perhaps you can get these in the size
you want.

It is sold by the drum, but I'm not sure as to what lengths,

>

 

[Terry Collins]

Magic Mushroom Farmer wrote:

I recall we took a truck load of copper, 1 ton of it for scrap 20
years ago and got $150 for it,must have trippled by now,as people go
crazy flogging the copper leads off junk yard stuff.
50 tons is alot of money....lol.

Last time (few months ago) I went to the recyclers, copper was $1/kg
(non-stripped cables) and Al was 1.13(?)/Kg.

the copper was a bit of a surprise as I had just cobbled together some
internal wiring from a sorting machine and internal computer cables. I
was expecting to be told they needed all the plugs cut off, but they
just picked up the full box, weighed it, dumped copper, weighed box and
paid for the difference.

 

[Terry Collins]

Magic Mushroom Farmer wrote:

What Cable has been used in the past for this type of
application.....

Is it economical to just runs some standard 240V heavy gauge cable in
parrallel? I know you can pick up drums of 240V 20Amp cable at various
places cheaply. Perhaps running 5 runs of that may give you what you
want cheaper.

 

[Phil Allison]

"Terry Collins"

Magic Mushroom Farmer wrote:

What Cable has been used in the past for this type of
application.....

Is it economical to just runs some standard 240V heavy gauge cable in
parrallel? I know you can pick up drums of 240V 20Amp cable at various
places cheaply. Perhaps running 5 runs of that may give you what you
want cheaper.

** Terry - I did the sums for you.

The OP needs 50,000 kilos of copper wire.

Get your calculator out and start with the fact that 1 metre of 1 sq mm
copper wire has 18 millohms resistance.




.......... Phil

 

[Mark Harriss]

Magic Mushroom Farmer wrote:

I recall we took a truck load of copper, 1 ton of it for scrap 20
years ago and got $150 for it,must have trippled by now,as people go
crazy flogging the copper leads off junk yard stuff.
50 tons is alot of money....lol.

I have some 7 strand IMAPI 10-20mm ,unsure what it was used
for....hydro earths?just looked at the power pole and they use even
bigger unsheilded stuff for their earths.
It is sheilded conductor wire...possibly that stuff they run to your
house from the transformer......cannot find specs on it.
I need big battery cable......this is what I need to ask/look for.....I
got the picture....thanks
Think I might go and check out an era gone by power station, everything
is long gone expect turbines sitting in a deep water filled hole,never
know,they used to drop water on trubines which powered 3 giant
alternators via belt drives....strange...thats how they did it
though....I am doing the same thing....just small scale.
Thanks again Phill.

$4 a kilo buy price where I am

 

[Terry Collins]

Phil Allison wrote:

"Terry Collins"

Magic Mushroom Farmer wrote:


What Cable has been used in the past for this type of
application.....

Is it economical to just runs some standard 240V heavy gauge cable in
parrallel? I know you can pick up drums of 240V 20Amp cable at various
places cheaply. Perhaps running 5 runs of that may give you what you
want cheaper.




** Terry - I did the sums for you.

The OP needs 50,000 kilos of copper wire.

Is that in one wire, or multiple strands?
Or would he be better off installing copper pipe (skin effect where
electrons prefer outside of strand to inside)?

Get your calculator out and start with the fact that 1 metre of 1 sq mm
copper wire has 18 millohms resistance.

I probably won't get far considering my brain is clearly aware that this
is Friday afternoon/evening and it wants to relax {.


So 400 metres gives ( 400 x 0.018) = 7.2 Ohm in one wire
therefore total resistance in one pair (there and back) is 14.4 Ohm
And if V = IR where V = 24V and I = 160 Amps,
there fore wire resistance needed is 0.15 Ohm, which means he needs 96
wires to get 160 Amps doing a nice loop out and back but no useful work
at any point {.

Actually that whole 160Amps thing has my ming boggling. I'm wondering it
it isn't easier to move the generator?

Plus, 160Amps must be something like welding 2" thick steel, so he is
going to require some huge special switches, otherwise the poor sucker
who has to throw that switch is going to want full leather kits (boots
to top of head) and arc welding visor?

Did I miss the revelation as to what this is for?

 

[Phil Allison]

"Jasen Bleatts"


** FUCK OFF - Jasen.

Large, friendly, brown persons are just about to have all the anglo puke's
arses on toast over there in NZ.

I sincerely hope they shove a 30 foot lamp post right up yours.

ASAP....





........ Phil

 

[Chris Jones]

Magic Mushroom Farmer wrote:

Hey I need to conduct 12VDC @ 130 AMP over 300-400m with minimal loss
and expense.(we all need to do this right?)
I have discovered that I may need some seriously heavy duty cable for
my power station.

Basics are understood that DC was no good for long runs therefore AC is
used.
7 to 12 miles for DC dose not ring bells!?

Questions:
Is It dumb to try to transport DC over such a distance?
What loss can I expect provided I can find a matching cable specific to
my requirments.?roughly(have been googling,but looking for been there
opinions)

What Cable has been used in the past for this type of
application......at a guess would it be right to assume,phone
cable?telegraph?amps rating? Old hydro cable?That copper cable they
used to run by the train tracks 20 years back?

Do I need to go 24VDC to get back to 12VDC at destination?(hate this
idea)

I can find 100amp cable in 100m rolls where do I look for bigger stuff
?

Finally is it worth AC over this distance?I would gather a similar
infustructure would need to be in place as with DC?

To tidy this up,what cable should I be looking at using?

Thanks in Advance

Tell me about what you are trying to do - where does the 160A at 12VDC come
from? Is it an alternator with a rectifier, or is it a DC generator with
brushes? This makes a big difference as to your options. If it is an
alternator with a rectifier, then you could either (a) have it rewound for
a higher voltage or (b) find a surplus transformer that can step the
voltage up to something more sensible. You need to think about the
frequency in this case because it will affect the spec of the transformer.

Also, what is your load? Are you storing the power in batteries? If so,
this might offer other opportunities such as moving the batteries and
inverter to the generator end of the cable.

Chris

 

[Mark Hathaway]

Hello Magic Mushroom,

I've plenty of experience running 25-30 volts up to 200 amps up to 30-40
meters for cinema xenon lamps and its a big enough hassle.


Working through the numbers, 100 amps at 12 volts at 400 meters using 120mm
tycab welding cable that has 0.161 ohms per 1000meters resistance and
assuming you can live with a 1.61 volt drop over the cable you'll need 8
runs of it.


The 35mm stuff in pvc jacket runs at about 22 bucks a meter on a 50 meter
drum. I've never used the 120mm2 stuff, but recall the 70mm2 stuff was a
kings ransom.

As others have pointed out, its beyond silly to go down this path.

Maybe a coupe of dc to ac inverters are the trick.

Good luck,

Mark




"Magic Mushroom Farmer" <jjbruce@gmail.com> wrote in message
news:1143107146.100575.322430@z34g2000cwc.googlegroups.com...

Hey I need to conduct 12VDC @ 130 AMP over 300-400m with minimal loss
and expense.(we all need to do this right?)
I have discovered that I may need some seriously heavy duty cable for
my power station.

Basics are understood that DC was no good for long runs therefore AC is
used.
7 to 12 miles for DC dose not ring bells!?

Questions:
Is It dumb to try to transport DC over such a distance?
What loss can I expect provided I can find a matching cable specific to
my requirments.?roughly(have been googling,but looking for been there
opinions)

What Cable has been used in the past for this type of
application......at a guess would it be right to assume,phone
cable?telegraph?amps rating? Old hydro cable?That copper cable they
used to run by the train tracks 20 years back?

Do I need to go 24VDC to get back to 12VDC at destination?(hate this
idea)

I can find 100amp cable in 100m rolls where do I look for bigger stuff
?

Finally is it worth AC over this distance?I would gather a similar
infustructure would need to be in place as with DC?

To tidy this up,what cable should I be looking at using?

Thanks in Advance

 

[Magic Mushroom Farmer]

Close...Fossil fuel costs money......Water in a river is
free...strapped to a car alternator.

 

[atec77]

Magic Mushroom Farmer wrote:

Hey....It is a water wheel running a regulated Alternator from a car.
I have learned I can trick the alternator into giving off more volts by
removing a diode or so.
Maybe 18volt....also the possibility of running in AC,then regulating
it back to 12vDC for an inverter.....thats if I can get enough power to
the destination.

I think my distance was more like,150m-200m however playing it safe.
As it is a costly exercise to experiment over this
distance....technical information or personal experience is a plus.
This is supposed to be a quick and dirty way to get some
power..lights...maybe a TV.
300W at the destination would be a good start.

Most people that are doing this are based close to their water wheels.
I

if its a normal 3phase alternator you should be able to get a usable ac

voltage from it , push it through a suitable transformer to step up and
deliver to site.

 

[Mark Hathaway]

"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:44252c94$0$491$61c65585@uq-127creek-reader-03.brisbane.pipenetworks.com.au...

Magic Mushroom Farmer wrote:
Maybe a coupe of dc to ac inverters are the trick.


Are you suggesting that at the power source(water trubine) convert it
to AC 240V via invertor,conduct it a couple hundred meters .....I do
want AC 240V at the destination....I can live with a slighly dodgy AC
power supply....been there many times over 100m with extenstion
cords...?


You could probably experiment with some older Fisher and Paykel washer
motors driven as alternators to get some higher voltages, they are three
phase though.

http://www.thebackshed.com/Windmill/assembly1.asp

They claim 0 to 300V unloaded at 2-3 amps for an unmodified winding.
You could probably bung a few on the one shaft and transmit high voltage
low current on three wires and use a 3 phase transformer at the far end.

Yes I am saying use an inverter to convert 12 volts dc to 240v ac


If the turbine produces a regulated 12 volts, then a 12v dc to 240v ac
inverter, such as the jaycar pn MI5088 1000watt inverter is the ticket. 10
or 15 amp 3 core wiring over 400 meters is no problem at all if done
properly, forget extension leads, use 3 core flex from the electrical shop
with connector boxes, will be cheapest to buy 4 drums of 100 meter flex I
think, but enquire.

If the turbine's output voltage follows rpm, its not going to be so easy. Do
you have any data, pics, etc of the turbine?


Regards,
Mark

 

[Mark Harriss]

Mark Hathaway wrote:

Yes I am saying use an inverter to convert 12 volts dc to 240v ac


If the turbine produces a regulated 12 volts, then a 12v dc to 240v ac
inverter, such as the jaycar pn MI5088 1000watt inverter is the ticket. 10
or 15 amp 3 core wiring over 400 meters is no problem at all if done
properly, forget extension leads, use 3 core flex from the electrical shop
with connector boxes, will be cheapest to buy 4 drums of 100 meter flex I
think, but enquire.

If the turbine's output voltage follows rpm, its not going to be so easy. Do
you have any data, pics, etc of the turbine?


Regards,
Mark

What turbine??, the OP's turbine?. Even using 240V flex will lose you
87.9 Volts based on the original poster's power requirements, 14 AWG 15A
copper wire and 800M round trip distance, this is 37% power loss. If he
could go as high as say 480V at half the current to 240V the power loss
would be 9% using the same resistance wire.A couple of 240V transformers
wired together could bring it back to a lower voltage suitable for
batteries and an inverter at the far end.