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Home > Archive > Electrical Engineering > May 2007 > Power line videos. Neat stuff
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Power line videos. Neat stuff
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| Andrew Gabriel 2007-05-15, 3:25 am |
| In article <U382i.151700$VU4.42733@bgtnsc05-news.ops.worldnet.att.net>,
"JohnR66" <nospam@att.net> writes:
> Confetti causes a flash over between power line conductors. I wonder why it
> travels horizontally like that?
> http://www.youtube.com/watch?v=abXAonbevaA
Do a search on Jacobs Ladder Arcs.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
| |
| phil-news-nospam@ipal.net 2007-05-15, 9:25 am |
| On Tue, 15 May 2007 01:31:32 GMT JohnR66 <nospam@att.net> wrote:
| Confetti causes a flash over between power line conductors. I wonder why it
| travels horizontally like that?
| http://www.youtube.com/watch?v=abXAonbevaA
|
| I thought this one was pretty neat. A linesman servicing HV lines from a
| chopper.
| http://www.youtube.com/watch?v=Hcal...related&search=
Do you have normal videos for these? YouTube still can't figure out what
version of Flash player my browser has (likely because their code does not
understand Linux).
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2007-05-15-0730@ipal.net |
|------------------------------------/-------------------------------------|
| |
| JohnR66 2007-05-15, 9:25 am |
| "Andrew Gabriel" <andrew@cucumber.demon.co.uk> wrote in message
news:46496158$0$639$5a6aecb4@news.aaisp.net.uk...
> In article <U382i.151700$VU4.42733@bgtnsc05-news.ops.worldnet.att.net>,
> "JohnR66" <nospam@att.net> writes:
>
> Do a search on Jacobs Ladder Arcs.
>
> --
> Andrew Gabriel
> [email address is not usable -- followup in the newsgroup]
Heat seems to pull the arc up, but this is horizontal and judging by the
sparks there is little or no wind.
John
| |
| John Rye 2007-05-15, 5:25 pm |
| Hello All
In article <r5i2i.154244$VU4.123100@bgtnsc05-news.ops.worldnet.att.net>,
JohnR66 <nospam@att.net> wrote:
> "Andrew Gabriel" <andrew@cucumber.demon.co.uk> wrote in message
> news:46496158$0$639$5a6aecb4@news.aaisp.net.uk...
[color=darkred]
> Heat seems to pull the arc up, but this is horizontal and judging by the
> sparks there is little or no wind.
I have not seen the video, but if you have a pair of parallel wires, and
establish an arc between them it will travel along the wires away from the
power source. Remembering that the arc could be replaced by a piece of wire,
if you work out the force on the piece of wire, by doing the appropriate
integrations on the fundamental equation Force = Flux Density x Current x
Length you will find that with a few thousand amperes of current there is a
significant force in this direction.
There is a message in this for those investigating equipment failures. That
is that the major damage will be where the arc ends up. The place where the
failure started is usually somewhere back towards the supply from this point.
You can usually find a series of bright spots on the conductor where the arc
was stationary for a few milliseconds.
If you consider single phase ac supplies the arc will often go out for a
short time at current zero and then restrike.
John
--
John Rye
Hadleigh IPSWICH England
<http://web.ukonline.co.uk/jrye/index.html>
---< On Line using an Acorn StrongArm RiscPC >---
| |
| The Great Attractor 2007-05-16, 9:25 am |
| On Tue, 15 May 2007 01:31:32 GMT, "JohnR66" <nospam@att.net> wrote:
>Confetti causes a flash over between power line conductors. I wonder why it
>travels horizontally like that?
Some local lines have coatings on them, and the burn travels along as
the coating is breeched.
>http://www.youtube.com/watch?v=abXAonbevaA
>
>I thought this one was pretty neat. A linesman servicing HV lines from a
>chopper.
>http://www.youtube.com/watch?v=Hcal...related&search=
| |
| The Great Attractor 2007-05-16, 9:25 am |
| On 15 May 2007 07:29:29 GMT, andrew@cucumber.demon.co.uk (Andrew Gabriel)
wrote:
>In article <U382i.151700$VU4.42733@bgtnsc05-news.ops.worldnet.att.net>,
> "JohnR66" <nospam@att.net> writes:
>
>Do a search on Jacobs Ladder Arcs.
Totally incorrect. Such arcs operate on the rise of heat in air. This
was HORIZONTAL.
Think before you speak, boy.
| |
| The Great Attractor 2007-05-16, 9:25 am |
| On 15 May 2007 12:31:24 GMT, phil-news-nospam@ipal.net wrote:
>On Tue, 15 May 2007 01:31:32 GMT JohnR66 <nospam@att.net> wrote:
>
>| Confetti causes a flash over between power line conductors. I wonder why it
>| travels horizontally like that?
>| http://www.youtube.com/watch?v=abXAonbevaA
>|
>| I thought this one was pretty neat. A linesman servicing HV lines from a
>| chopper.
>| http://www.youtube.com/watch?v=Hcal...related&search=
>
>Do you have normal videos for these? YouTube still can't figure out what
>version of Flash player my browser has (likely because their code does not
>understand Linux).
What I hate is all these damned sites that allow one to view, but not
save a clip.
They act like they are going to lose money or some such SPAM related
CRAP.
| |
| The Great Attractor 2007-05-16, 9:25 am |
| On Tue, 15 May 2007 17:18:52 +0100, John Rye <jrye@ukonline.co.uk> wrote:
>Hello All
>
>In article <r5i2i.154244$VU4.123100@bgtnsc05-news.ops.worldnet.att.net>,
> JohnR66 <nospam@att.net> wrote:
>
>
>I have not seen the video, but if you have a pair of parallel wires, and
>establish an arc between them it will travel along the wires away from the
>power source. Remembering that the arc could be replaced by a piece of wire,
>if you work out the force on the piece of wire, by doing the appropriate
>integrations on the fundamental equation Force = Flux Density x Current x
>Length you will find that with a few thousand amperes of current there is a
>significant force in this direction.
Pretty silly. Arcs find least resistance paths, period. Air ionizes
around them, and some lines are coated, so an arc could move in either
direction.
These were parallel lines, so it likely moved along them as it breeched
the coating on them, blazing a trail as it were.
>
>There is a message in this for those investigating equipment failures. That
>is that the major damage will be where the arc ends up. The place where the
>failure started is usually somewhere back towards the supply from this point.
>You can usually find a series of bright spots on the conductor where the arc
>was stationary for a few milliseconds.
Any arc that remains stationary is going to heat up the start and
finish points (which each is both for AC) heavily at the location where
it stands in one place.
>
>If you consider single phase ac supplies the arc will often go out for a
>short time at current zero and then restrike.
>
Since all three phases are not carried on ONE pair of lines, the same
occurs one a three phase system where the arc is typically only on one of
the phases.
| |
| phil-news-nospam@ipal.net 2007-05-16, 9:25 am |
| On Wed, 16 May 2007 02:49:32 -0700 The Great Attractor <SuperM@ssiveblackholeatthecenterofthemilkywaygalaxy.org> wrote:
| On 15 May 2007 12:31:24 GMT, phil-news-nospam@ipal.net wrote:
|
|>On Tue, 15 May 2007 01:31:32 GMT JohnR66 <nospam@att.net> wrote:
|>
|>| Confetti causes a flash over between power line conductors. I wonder why it
|>| travels horizontally like that?
|>| http://www.youtube.com/watch?v=abXAonbevaA
|>|
|>| I thought this one was pretty neat. A linesman servicing HV lines from a
|>| chopper.
|>| http://www.youtube.com/watch?v=Hcal...related&search=
|>
|>Do you have normal videos for these? YouTube still can't figure out what
|>version of Flash player my browser has (likely because their code does not
|>understand Linux).
|
|
| What I hate is all these damned sites that allow one to view, but not
| save a clip.
|
| They act like they are going to lose money or some such SPAM related
| CRAP.
If you can view it, you can save it. You just have to be using software
that obeys the user, or something sniffing the video card buffers. BTW,
features in the new Vista from Microsoft intentonally try to prevent that.
I would not mind watching the video directly from YouTube, if they would
make it work universally. But that probably means they would ose certain
abilities to control other people.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2007-05-16-0813@ipal.net |
|------------------------------------/-------------------------------------|
| |
| John Rye 2007-05-16, 1:25 pm |
| Hello
In article <qvkl43hjir48u3d3je88ds68umovm3g9f6@4ax.com>,
The Great Attractor <SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
> On Tue, 15 May 2007 17:18:52 +0100, John Rye <jrye@ukonline.co.uk> wrote:
[color=darkred]
> Pretty silly. Arcs find least resistance paths, period. Air ionizes
> around them, and some lines are coated, so an arc could move in either
> direction.
Agreed that arcs normally find the least resistance path.
Agreed that if the conductors are insulated it will slow the movemant down.
But you are forgeting the magnetic forces. The arc will move away from the
power source, and I have plenty of videos from experiments demonstrating
this. Unfortunately they are on film, and can not therefore easily be put on
the web.
> These were parallel lines, so it likely moved along them as it breeched
> the coating on them, blazing a trail as it were.
[color=darkred]
> Any arc that remains stationary is going to heat up the start and
> finish points (which each is both for AC) heavily at the location where
> it stands in one place.
[color=darkred]
> Since all three phases are not carried on ONE pair of lines, the same
> occurs one a three phase system where the arc is typically only on one of
> the phases.
Sorry but no. The arc will run on all 3 phases. If you look at a high speed
film you can see the current zeros occuring on each phase, but except for
these very short breaks, on a three conductor arrangement with bare
conductors there will be arcs on all three conductors.
John
--
John Rye
Hadleigh IPSWICH England
<http://web.ukonline.co.uk/jrye/index.html>
---< On Line using an Acorn StrongArm RiscPC >---
| |
| Don Kelly 2007-05-16, 9:25 pm |
| ----------------------------
"The Great Attractor"
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote in message
news:dpkl435g4tiioakr2hhk5qbrmv6ttd6j72@4ax.com...
> On 15 May 2007 07:29:29 GMT, andrew@cucumber.demon.co.uk (Andrew Gabriel)
> wrote:
>
>
>
> Totally incorrect. Such arcs operate on the rise of heat in air. This
> was HORIZONTAL.
>
> Think before you speak, boy.
--------------
There is a short between lines - current flows- magnetic force is present
and tends to expand the loop and this alone can cause movement of the arc
(and is also a major factor in Jacob's Ladders-more so than thermal
effects).
This arc had little upward expansion so heating wasn't the source. A
horizontal Jacobs ladder should work.
Fats, you should be able to try this.
--
Don Kelly dhky@shawcross.ca
remove the X to answer
| |
| Don Kelly 2007-05-17, 3:25 am |
| ----------------------------
"John Rye" <jrye@ukonline.co.uk> wrote in message
news:4ee3f7e178jrye@ukonline.co.uk...
> Hello
>
> In article <qvkl43hjir48u3d3je88ds68umovm3g9f6@4ax.com>,
> The Great Attractor
> <SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>
>
>
> Agreed that arcs normally find the least resistance path.
>
> Agreed that if the conductors are insulated it will slow the movemant
> down.
>
> But you are forgeting the magnetic forces. The arc will move away from the
> power source, and I have plenty of videos from experiments demonstrating
> this. Unfortunately they are on film, and can not therefore easily be put
> on
> the web.
>
>
>
>
>
>
> Sorry but no. The arc will run on all 3 phases. If you look at a high
> speed
> film you can see the current zeros occuring on each phase, but except for
> these very short breaks, on a three conductor arrangement with bare
> conductors there will be arcs on all three conductors.
>
> John
>
> --
> John Rye
> Hadleigh IPSWICH England
> <http://web.ukonline.co.uk/jrye/index.html>
> ---< On Line using an Acorn StrongArm RiscPC >
---------------
Actually the most common arcing fault on a 3 phase system is line to ground
on one phase. However, it can, if not cleared become 2 line to ground and
then involve all 3 phases.
In many cases single pole clearing and reclosure works well.
--
Don Kelly dhky@shawcross.ca
remove the X to answer
---
| |
| The Great Attractor 2007-05-17, 9:25 am |
| On 16 May 2007 13:15:59 GMT, phil-news-nospam@ipal.net wrote:
>On Wed, 16 May 2007 02:49:32 -0700 The Great Attractor <SuperM@ssiveblackholeatthecenterofthemilkywaygalaxy.org> wrote:
>| On 15 May 2007 12:31:24 GMT, phil-news-nospam@ipal.net wrote:
>|
>|>On Tue, 15 May 2007 01:31:32 GMT JohnR66 <nospam@att.net> wrote:
>|>
>|>| Confetti causes a flash over between power line conductors. I wonder why it
>|>| travels horizontally like that?
>|>| http://www.youtube.com/watch?v=abXAonbevaA
>|>|
>|>| I thought this one was pretty neat. A linesman servicing HV lines from a
>|>| chopper.
>|>| http://www.youtube.com/watch?v=Hcal...related&search=
>|>
>|>Do you have normal videos for these? YouTube still can't figure out what
>|>version of Flash player my browser has (likely because their code does not
>|>understand Linux).
>|
>|
>| What I hate is all these damned sites that allow one to view, but not
>| save a clip.
>|
>| They act like they are going to lose money or some such SPAM related
>| CRAP.
>
>If you can view it, you can save it. You just have to be using software
>that obeys the user, or something sniffing the video card buffers. BTW,
>features in the new Vista from Microsoft intentonally try to prevent that.
>
>I would not mind watching the video directly from YouTube, if they would
>make it work universally. But that probably means they would ose certain
>abilities to control other people.
Try "Devil Ducky" and hunt up the same clip.
http://www.devilducky.com/all/
| |
| The Great Attractor 2007-05-17, 9:25 am |
| On Wed, 16 May 2007 17:20:24 +0100, John Rye <jrye@ukonline.co.uk> wrote:
>
>Sorry but no. The arc will run on all 3 phases. If you look at a high speed
>film you can see the current zeros occuring on each phase, but except for
>these very short breaks, on a three conductor arrangement with bare
>conductors there will be arcs on all three conductors.
>
>John
Look again. THAT WAS a three phase line, but only two lines were
arcing.
Nice guess though.
| |
| The Great Attractor 2007-05-17, 9:25 am |
| On Thu, 17 May 2007 02:21:31 GMT, "Don Kelly" <dhky@shaw.ca> wrote:
>----------------------------
>"The Great Attractor"
><SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote in message
>news:dpkl435g4tiioakr2hhk5qbrmv6ttd6j72@4ax.com...
>--------------
>
>There is a short between lines - current flows- magnetic force is present
>and tends to expand the loop and this alone can cause movement of the arc
>(and is also a major factor in Jacob's Ladders-more so than thermal
>effects).
>This arc had little upward expansion so heating wasn't the source. A
>horizontal Jacobs ladder should work.
>Fats, you should be able to try this.
I have had jacob's ladders where the arc sits at the bottom without
moving up the conductor pair at all.
The thing needed adjustment, and the ACTION was effected by THERMAL
energy carrying the arc up the non parallel conductor pair. Since the
top is wide, when the arc finally quenched, a new arc forms at the bottom
(least resistance path), and the process starts again.
It is 100% thermal in air, with the ONLY exception being in a vacuum
vessel. Then, I would suspect that there is STILL some air in there.
Are there DC Jacob's ladders?
| |
|
|
| Don Kelly 2007-05-18, 3:25 am |
| "The Great Attractor"
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote in message
news:qn9o43te2m6u7oqh67dcghbjvrp78i3im9@4ax.com...
> On Thu, 17 May 2007 02:21:31 GMT, "Don Kelly" <dhky@shaw.ca> wrote:
>
>
>
> I have had jacob's ladders where the arc sits at the bottom without
> moving up the conductor pair at all.
>
> The thing needed adjustment, and the ACTION was effected by THERMAL
> energy carrying the arc up the non parallel conductor pair. Since the
> top is wide, when the arc finally quenched, a new arc forms at the bottom
> (least resistance path), and the process starts again.
>
> It is 100% thermal in air, with the ONLY exception being in a vacuum
> vessel. Then, I would suspect that there is STILL some air in there.
>
> Are there DC Jacob's ladders?
Of course, in a Jacob's ladder, the current is small-typically the supply
is a Neon transformer. In a power line arc, the current will be much higher
and magnetic forces will be appreciable (it doesn't actually take much force
to move the arc). Have you heard of magnetic blowout on LV breakers? Sure a
Jacob's ladder is vertical a) get a little boost from thermal forces. b)
takes up less floor space leaving more room for spectators. c) Thermal
effects help clear the arc at the end (the arc collapses at current 0 so air
movement can break up the arc path).
Yes, I've seen Jacobs ladders for which the arc didn't move. So?
As for a DC Jacob's Ladder- definitely and with a more spectacular effect
such as the arc reaching the end and stretching much further than an AC arc
(at the same current) before going out. Not sure that I would want one.--
Don Kelly dhky@shawcross.ca
remove the X to answer
----------------------------
| |
| Tomi Holger Engdahl 2007-05-23, 5:25 pm |
| phil-news-nospam@ipal.net writes:
> On Wed, 16 May 2007 02:49:32 -0700 The Great Attractor <SuperM@ssiveblackholeatthecenterofthemilkywaygalaxy.org> wrote:
> | On 15 May 2007 12:31:24 GMT, phil-news-nospam@ipal.net wrote:
> |
> |>On Tue, 15 May 2007 01:31:32 GMT JohnR66 <nospam@att.net> wrote:
> |>
> |>| Confetti causes a flash over between power line conductors. I wonder why it
> |>| travels horizontally like that?
> |>| http://www.youtube.com/watch?v=abXAonbevaA
> |>|
> |>| I thought this one was pretty neat. A linesman servicing HV lines from a
> |>| chopper.
> |>| http://www.youtube.com/watch?v=Hcal...related&search=
> |>
> |>Do you have normal videos for these? YouTube still can't figure out what
> |>version of Flash player my browser has (likely because their code does not
> |>understand Linux).
> |
> |
> | What I hate is all these damned sites that allow one to view, but not
> | save a clip.
> |
> | They act like they are going to lose money or some such SPAM related
> | CRAP.
>
> If you can view it, you can save it.
That's true. There are some nice extensions for Firefox web broser that
allows you to easily download videos from many sites, including YouTube.
Use Firefox web browser with VideoDownloader plug-in and you can download
videos easily. Get fre FLV player application and you can play easily
those downloaded flash videos.
> You just have to be using software
> that obeys the user, or something sniffing the video card buffers. BTW,
> features in the new Vista from Microsoft intentonally try to prevent that.
>
> I would not mind watching the video directly from YouTube, if they would
> make it work universally. But that probably means they would ose certain
> abilities to control other people.
>
> --
> |---------------------------------------/----------------------------------|
> | Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
> | first name lower case at ipal.net / spamtrap-2007-05-16-0813@ipal.net |
> |------------------------------------/-------------------------------------|
--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
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