Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: Energy from the Ground - Self powered generator by Barbosa and Leal  (Read 1732130 times)

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1845 on: April 27, 2015, 09:17:00 PM »
I found an excellent link for a SWER system test done by am amateur experimenter.

This is a decent experiment with real numbers and sets a good example.

http://www.aprs.org/aprs-swer-test.html

Test Setup: We found a rural road, stuck a broom handle out the window and let a 3200 foot roll of #20 wire fly from a small 6" spool. We cut a normal 8' copper clad steel ground rod into three pieces and drove them into the ground about 4 feet apart. That was one end. (not shown).

Then at the other end (the hiking end) we used four very small 2 foot rods 3/16ths inch) spaced about 3 feet apart that you can see in the image to the right. The path length was about .45 mile or 2500 feet between ground rods (though I had 3200 feet of wire but just ran out of straight road). The wire resistance was about 35 Ohms. To simplify the test so that we did not have to be at both ends at once, we simply grounded the distant end of the wire to the original 3 copper-clad rods, and did both the source and load at the same end shown here (with son AJ, WA4APR holding wire).

Using only 214 VDC input (conveniently from the Prius),we got a 100W light to normal brilliance (measured 115 volts across it) meaning there was 100 volts loss in the ground loop system. This implied a 100 Ohm loop system (32 ohms was in my wire). So we achieved about 65 Ohms ground system with my little rods. Doubling the depth of the rods or the number of rods would halve the resistance.

Performance of 4 rods yielded 114 volts to bulb
Performance of 3 rods dropped voltage to 108
Performance of 2 rods dropped voltage to 82
Performance of 1 rod dropped voltage to 47.

The 100 Watt bulb of course is very non-linear, so I will have to bench test it to find out what the currents were drawing at the other 3 test points. But because of the spacing of the rods being farther than the depth of the rods, the resistance should have been relatively independent yielding a linear response to the number of rods.

GROUND RODS: Since conventional SWER Power systems deliver hundreds of Kw using grounds as simple as 30 foot single rods or more as needed. A 10 ohm ground resistance is ideal in moist soil as shown to the right. Halving the depth of a rod increases the resistance by probably a factor of 2.5. Doubling the number of rods reduces the resistance by a factor of 2 as long as they are as far apart as deep. Our small system goal is about 50-100 Ohms so we can go with a single 8 foot rod or two 4 foot rods, or four 2 foot rods. I prefer the shorter rods because they are easy to remove.

I'd say our test soil is "farming, loamy and clay" and so a 3 meter rod (10 feet) would give us about 33 ohms. But we used only four 2 foot rods, (equivalent to about a single 5 foot rod maybe and so we got double this or about 66 ohms over the 2000 feet of earth which seems consistent with the table..

Conclusion: This test was entirely satisfactory. Especially since in practice, we will not use the Prius battery, but will use a 150 watt 115 VAC inverter from the vehicle 12v system so that we have complete isolation of the SWER loop from the vehicle. We will use 2 caps and 2 diodes to double that to 330 VDC which will further reduce the loss in the loop resistance. In any case, we will have more than enough power to power a 50 Watt station on the mountain top.

See the APRS-SWER web page.

SWER systems can be done just as safely as other power distribution systems if done correctly. They can also be done dangerously by those not fully understanding the principles involved. Do not try this at home!

Bob, WB4APR

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1846 on: April 27, 2015, 09:38:42 PM »
Hark yonder...

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1847 on: April 27, 2015, 09:47:10 PM »
More on resistance...

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1848 on: April 27, 2015, 09:54:43 PM »
You guys are just going to L O V E this one because it's from 1901.  So it has street cred.

http://earlyradiohistory.us/1901fa21.htm

 Earth-currents or Leakages.

    When a linear conductor dips at each end into the earth, and voltage is impressed upon it by any means, the resulting return current would probably flow through the earth in a straight line between these two points if the conductibility of the earth were perfect; but as the earth, per se, is a very poor conductor (and probably is so only because it is moist), lines of current-flow spread out symmetrically in a way that recalls the figure of a magnetic field. These diffused currents are evident at great distances, and can be easily traced by means of exploring earth-plates or rods. The primary current is best produced by alternating currents of such a frequency as to excite a distinct musical note in a telephone, and if these currents rise and fall periodically and automatically, they produce an unmistakable wail, which, if made and broken by a Morse key into short and long periods, can be made to represent the dots and dashes of the Morse alphabet. The secondary circuit, which contains the receiving telephone, is completed in the case of an earth area by driving two rods into the ground, and in the case of water by dipping plates therein, 5 to 10 yards apart.
    It is therefore necessary to be able to distinguish these earth-currents from those due to induction, as they are apt to give false effects, and to lead to erroneous conclusions. This is easily done, if the instrument be sensitive enough, by making the primary current continuous when the earth-current also becomes continuous, whereas the induction currents will be momentary, and will only be observed at the beginning and end of the primary or inducing current.

Look!  The attached images from 1901 show you how the current actually flows in the ground!

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1849 on: April 27, 2015, 10:04:56 PM »
Moisture and salt content....

a.king21

  • Hero Member
  • *****
  • Posts: 1650
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1850 on: April 27, 2015, 11:06:34 PM »
Milehigh: we could do with your electrical knowledge input here:


https://www.youtube.com/watch?v=lGIJSWirhPw

Farmhand

  • Hero Member
  • *****
  • Posts: 1583
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1851 on: April 28, 2015, 12:37:06 AM »
Looks to me like Tesla showed/used the single wire Earth return in the patent below but he doesn't lay claim to the idea so it seems the principal has been around for a very long time. Pre Tesla.

Tesla Patent.
http://www.google.com/patents/US593138

Others have implemented it in modern times, we use it in Australia and it is not as safe as they make out. A SWER line was responsible for a very bad bush fire that killed a 173 people and destroyed many properties.

It happens when the HV line comes down but does not actually trip the breakers and such, this leads to the line starting a fire through a resistance.
If the line comes down on trees the resistance can be too high to trip the breakers or whatever and the tree can catch fire due to the current through it.

Quote
The Royal Commission concluded that five of the major fires that it investigated were started
by powerlines
2
. In its July 2010 Final Report, the Royal Commission concluded that
3
:
The SWER and 22kV distribution networks constitute a high risk for bushfire ignition,
along with other risks posed by the ageing of parts of the networks and the particular
limitations of SWER lines.
The Royal Commission made 67 recommendations, of which eight (Recommendations 27 –
34) relate to reducing the likelihood of powerlines starting catastrophic bushfires. These
recommendations have been accepted by the Victorian Government.
   

Powerline bushfire report.
http://www.esv.vic.gov.au/Portals/0/About%20ESV/Files/RoyalCommission/PBST%20final%20report%20.pdf
..

Lightning strikes to trees can leave behind trees that are half dead and half alive, like one side of the tree will die but one side can live, such a tree would be great for starting a fire, maybe even a dead or a live tree can do it. I see no real world tests on this.

..

SWER lines can also produce potentials along the current path of up to 40 volts per meter or so at the ground surface, and I read a article that warns of possible dangers to livestock. If a human walked in bare feet on the wet ground in the line of the flow of current and took a long step the person might be able to feel the up to 40 volts 50 Hz AC first hand.Livestock have a longer gait than a human can be over 1 meter.

..

I think the words should be that "It can be safe", but there is 170 odd Australians that also say it can also be very deadly and destructive.

..

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1852 on: April 28, 2015, 04:20:19 AM »
Farmhand:

That is a very unfortunate story.  Note that regular power lines could also short with trees and cause fires.

The real issue is that it was a design and/or implementation or verification or maintenance failure and a person or persons could be legally liable and subject to criminal prosecution.  Somebody signed off on a drawing and then it was implemented in the field.  Presumably this was a civil or electrical engineer.  They also had to visit the site and approve the construction and sign off on that also.  Then there is a maintenance log book somewhere.

I am just making assumptions and I am not going to look up the story.  But people were the true source of the problem.

MileHigh

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1853 on: April 28, 2015, 04:23:31 AM »
Pop quiz no Googling:  If there is a break in a long distance transmission line, how do you find it?

Pirate88179

  • elite_member
  • Hero Member
  • ******
  • Posts: 8366
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1854 on: April 28, 2015, 04:32:40 AM »
Pop quiz no Googling:  If there is a break in a long distance transmission line, how do you find it?

By the fire?  (Follow the smoke)

Just kidding.

By "you" I assume you mean the power company right?

If the line has not shorted out and blown something on either end of the circuit,  I assume they could test the resistance of the two parts and with some math, determine how far down the line the break is.  (Total guess here)  They already know the wire diameter and ohms/foot.

Bill

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1855 on: April 28, 2015, 04:40:46 AM »
Bzzzzzt!

Pirate88179

  • elite_member
  • Hero Member
  • ******
  • Posts: 8366
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1856 on: April 28, 2015, 04:42:23 AM »
Bzzzzzt!

Can I phone a friend? (At least you know I did not Google it)

Bill

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1857 on: April 28, 2015, 04:51:02 AM »
You can only dream that if you had Manuela on your side...

https://www.youtube.com/watch?v=UmsyEMFYsus

Pirate88179

  • elite_member
  • Hero Member
  • ******
  • Posts: 8366
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1858 on: April 28, 2015, 05:04:41 AM »
You can only dream that if you had Manuela on your side...

https://www.youtube.com/watch?v=UmsyEMFYsus

Wow!  She has great legs.  Is that my consolation prize?

Bill

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: Energy from the Ground - Self powered generator by Barbosa and Leal
« Reply #1859 on: April 28, 2015, 05:17:07 AM »
Check out the subliminal messages in this video!

(Damn that iPhone 6 has a good camera!)

https://www.youtube.com/watch?v=BtNguqonFWk