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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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18th Oct 2015, 7:19 pm | #41 | |
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Re: Pylons
Re the Namibia pylon...
Quote:
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18th Oct 2015, 8:44 pm | #42 |
Octode
Join Date: May 2003
Location: Belper Derbyshire
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Re: Pylons
It isn't just pylons that are interesting. If you look through the fences at some of the transformers, you can sometimes work out what is going on. There are lots of old and famous manufacturers names to be seen including Brush, English Electric, GEC ect.
Our site in Wakefield has a 11KV/33KV step up transformer and on the side has a nice vintage Ferranti automatic tap changer. Looking through the observation window there is a very nice looking mechanism made of machined brass inside. Christopher Capener
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18th Oct 2015, 10:47 pm | #43 |
Dekatron
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Re: Pylons
Hi,
I've always found electrical supply equipment fascinating, and wished I'd taken more photos when I was in the power industry and occasionally worked inside substation compounds. I love these old French tall substations (photos 1 & 5) with their terracotta tiled roofs which are slowly disappearing to be replaced with small package transformers. Photo 3 shows a small pylon in Spain which looks a bit of a mess (the tower, not Spain!) Photo 4 was taken during a wholesale replacement of insulators and cross arms on the 20Kv lines near our village. The local area was fed from four diesel generators while the work was carried out. Cheers, Pete.
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18th Oct 2015, 10:59 pm | #44 |
Dekatron
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Re: Pylons
There're a few pics of electrical distribution and power infrastructure on my 'Flickr' page, here:- https://www.***********/photos/russel...57603792374210
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19th Oct 2015, 1:33 am | #45 |
Dekatron
Join Date: Apr 2012
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Re: Pylons
One of the components I have seen many times that to me has no obvious purpose.
I would like to see if anyone knows what they are fitted for. To me they are just clipped onto the cables in pairs close to the insulators at each end of the cable run. Lightning gaps are obvious to me but these are not obvious. |
19th Oct 2015, 2:18 am | #46 |
Nonode
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,944
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Re: Pylons
They are vibration dampers - see the attachment.
Cheers, |
19th Oct 2015, 3:15 am | #47 |
Nonode
Join Date: Jan 2009
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Re: Pylons
In fact the use of two ground wires appears to be standard practice for high voltages where the three phase wires are horizontally arrayed, as in the case of what might be called the classic steel lattice transmission tower form.
Cheers, |
19th Oct 2015, 8:03 am | #48 |
Dekatron
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Re: Pylons
Stockbridge dampers. They're used to dampen aeolian vibrations set up by the wind. Used on HF curtain arrays too.
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19th Oct 2015, 8:18 am | #49 |
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Re: Pylons
Some structures exhibit wind-powered vibrations, and the forces can be a bit much for the structure. The classic example is the Tacoma Narrows bridge 'Galloping Gertie' - it's worth finding the film of it if you've never seen it. Also the original Severn bridge turned out to have aerodynamic problems that forced modifications.
Simpler shapes like cylindrical cables are vulnerable to these effects too. You just need the right airflow to make the oscillation tune across a structural resonance and... David
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19th Oct 2015, 9:28 am | #50 |
Dekatron
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Re: Pylons
We had a fire in the garden caused by oscillating power cables
I was in the house....crack crack crack, rushed outside, it only took a me a few seconds, the grass (long) was on fire in six places, the oscillation was slapping together the two uninsulated overhead 230 volt incomer cables, we live in a timber clad house, there had been a long dry spell of weather...Anyways I put the fires out and the oscillation eventually stopped... Western Power were called out, the oscillations started again, not only on our 230 volt feed but on the 11Kv line that passes over the property boundary to the transformer pole, it turned out to be a horse rubbing it's bum on the utility pole cable stay that the transformer was on. Just an average day Lawrence. |
19th Oct 2015, 9:56 am | #51 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
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Re: Pylons
That reminds me of a news item that I read some years ago in, I think, the IEE news, about a stretch of power line on the south coast of England that suffered periodic trips in the autumn for no obvious reason. The cause was eventually traced to flocks of migrating birds, which assembled en mass on the lines to prepare for crossing the channel and then all took off at once. The reaction force of the instantaneous departure so many birds was enough to set the lines swinging and cause a flash-over.
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19th Oct 2015, 10:08 am | #52 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,394
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Re: Pylons
Resonance dampers. Look for them on suspension bridge cables and other places where unwanted resonances are likely- the Humber bridge is strewn with them, although care was taken at design.They're one of those things that, once you're aware of them, they seem to be all over the place
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19th Oct 2015, 11:06 am | #53 |
Dekatron
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Re: Pylons
As a land owner I can tell you that in vaguely recent times a retrospective legal operation is going on to lease the right to the optic fibre that must have been there for ages. I don't know why, but am guessing that maybe this is to do with using it for purposes nothing to do with the electric companies. I am arguing with them about this as the quite generous deal comes with a lot of nasty restrictions, way more onerous than the de-facto safety issues with the pylon itself.
By the way, you may not realise that pylons host rainbow generators. Don't believe me? Well here is a photo! You can see the rainbow projector, cleverly disguised as a microwave link, glowing away Also, the answer to the question about what is at the end of a rainbow is clearly shown here - another pylon, obviously. |
19th Oct 2015, 12:09 pm | #54 |
Octode
Join Date: Jul 2008
Location: Gloucestershire, UK.
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Re: Pylons
Hello,
Strong wind can produce what are known as "galloping conductors". http://www.tdee.ulg.ac.be/player.php...2loops512k.flv http://www.tdee.ulg.ac.be/player.php...pndown512k.flv Yours, Richard |
19th Oct 2015, 1:31 pm | #55 |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
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Re: Pylons
There is a 3 phase HV line out near Bournemouth with horizontal wires rather than vertical it has 2 earth wires above it which seems to point to the use of twin earth wires for these being common practice. Russell loved your photo collection very interesting.
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19th Oct 2015, 1:47 pm | #56 |
Dekatron
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Location: Charmouth, Dorset, UK.
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Re: Pylons
I was leaving a cottage in the aforementioned Fishpond on day when I heard a loud bang behind me and turned just in time to see the body of a large crow falling from an 11kv pole to the ground, it had somehow connected itself across the 11kv supply.
Peter |
19th Oct 2015, 5:19 pm | #57 |
Dekatron
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Location: Cornwall, UK.
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Re: Pylons
When they replaced the 11kv poles and line not that long ago on our stretch they put taller ones in, they used a Philipino crew, boy do those guys work.
Our ash tree is about 3 ft short of the line, they are due out soon to pollard it, one of the 11Kv poles is on our land but when I last checked the wayleave payment was meager, I couldn't be bothered at the time. Lawrence. |
19th Oct 2015, 7:31 pm | #58 | |
Dekatron
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Re: Pylons
Quote:
On my 11/33Kv 3-phase infrastructure the same function is provided by a short overwind spiral of wire [same thickness as the transmission-line] fitted either side of the insulators. I guess they form offcuts of the main transmission-line . . . |
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19th Oct 2015, 7:39 pm | #59 |
Dekatron
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Re: Pylons
Are you sure that's not a cable repair? The procedure is to wrap overound spirals of wire onto the conductors to strengthen chafing and damage, using a thing called a 'Parrot's Beak'.
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19th Oct 2015, 7:43 pm | #60 |
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Re: Pylons
The process of wrapping a wire back around itself, I think, is called 'serving' for thread, it's called 'whipping'
Amazing the junk that lurks in the back of the head. David
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