just springs?

What are those things holding the power lines up in this photo?
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Are those just springs, or is it something electrical?
Reply to
bob
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No they're not springs, they're insulators. Check out these photos on Google:
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Reply to
Rich.
Thanks. In layman's terms, can someone tell me what they do? Are they basically just holding the wire?
Reply to
bob
Yes and avoiding current flow into the plylon by being insulators, but the interesting question you are probably asking "why do they look like springs?"
Pass....
Reply to
Adrian C
That design allows for more temperature expansion and contraction extremes without cracking the insulator materials, as apposed to a solid surface design.
Reply to
Rich.
I can't see very well the insulators in the picture but sometime the stacked wafers are to effectively increase the arc gap.
"why do they look like springs?" I don't know. Why do some clouds look like Mickey Mouse? Tom
Reply to
Tom Biasi
The old ones were modular and one insulator section could be replaced out of the string. Probably still are.
The shape of a single section is curved on top and prestty flat with circular waves on the bottom. Worst leakage is on the surface when the insulators are wet. The shape greatly increases the surface path length. The curved top tends to keep the flat underside dry.
-- bud--
Reply to
bud--
Thanks. I can recall as a young man camping under the power line and on a damp night we could hear arcing. Tom
Reply to
Tom Biasi
Thanks. I can recall as a young man camping under the power line and on a damp night we could hear arcing. Tom
What you heard was "corona" It is a situation where there is local ionization of the air -generally at points (even raindrops on the conductors) but it is localized by weaker fields away from these points so that a conductive path is not made between conductors or conductor to ground and there is no arcing. However It does cause glowing streamers etc and produces both audio and RF noise as well as ozone. If you test an insulator in a darkened lab- you will see a glow and hear noise and this will increase as you raise the voltage- then you may get some quick flashes over the insulator if humidity is high but there is a fine line between this state and flashover leading to an arc which has as high a current as the source will allow. With a uniform air gap- the conditions that cause corona will cause a flashover and an arc will follow.
Don Kelly cross out to reply
Reply to
Don Kelly
Yes corona would be the correct term. Your compass doesn't work well near the towers either.
Reply to
Tom Biasi
Another way of putting it is that there is no completed metallic conductive path. The circuit is completed using Maxwell's displacement current. Charge is mobile where the air breaks down but not over the entire path.
Reply to
Salmon Egg

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