Vapin' Joe
Formerly known as Smokin Joe
- Location
- Bare headed cyclist, Smoker
I'm sure Beckham used to lie awake all night thinking about that one.
Calling @swansonj ....
- Thread starter Fab Foodie
- Start date
Page may contain affiliate links. Please see terms for details.
srw
It's a bit more complicated than that...
No.
I think David Icke was touting that one to explain why we cant see the 12ft LizardsInterestingly, I read (I say read, I understood the words but not their meaning) on the BBC website that the universe might be a 'simulation' as portrayed in the Matrix films. Hmmm...
http://www.bbc.com/earth/story/20160901-we-might-live-in-a-computer-program-but-it-may-not-matter
But we all know, so don't have to.
Coronas were covered in an earlier lecture in the series. I've got the notes somewhere if you want them.
Damned secret societies! whose chain do you need to mickle to get some answers around here?But we all know, so don't have to.
So what do you want to know about coronal discharge? I'm sure I can answer your questions for a small fee.
swansonj
Guru
Yes. Take a gold star that man.
Edit: unless you're engaging in some complicated euphemism. In which case I'll have star back please.
Do you think he is ready to hear about partial discharge?
srw
It's a bit more complicated than that...
It's simply the 21st century version of the Brain in the Vat theory - a perfectly respectable thread within the Philosophy of Mind which (wiki reminds me) dates back to Descartes. How we understand consciousness is still a very live problem in psychology and philosophy.
srw
It's a bit more complicated than that...
I'm not proud. What is a corona in relation to electricity?
swansonj
Guru
Well, it's "corona" rather than "a corona" or "coronal", but I'm so delighted at someone asking that I'm hardly likely to be fussy about that
It's when the electric field on the surface of the wires, produced by their voltage, is high enough to strip electrons off air molecules or, in the jargon, cause ionisation. Most of the ions thus created recombine almost immediately, a very few escape, but corona is an energy loss and is what causes the occasional audible crackling noise and, rather rarely, radio interference, so it's not a good thing. So we design our lines so that the electric field on the surface of the conductors is below the corona threshold (it's all to do with the radius of the wires and the number and spacing of the 2, 3 or 4 wires in each bundle - more wires is better, which is why you never get single wires at the highest voltages even if you only actually need one for the required current).
But the electric field gets enhanced by any irregularity - the sharper the object the worse - it's the same physics but opposite objective to lightning conductors, which are made pointed in order to attract discharges. So even with an impeccably designed conductor system you will get corona if there are drops of water, or a nice kind farmer has just harvested her field and all the chaff has stuck to the wire.
And that, dear reader, is why power lines crackle more in the wet.
srw
It's a bit more complicated than that...
It's all a long way from batteries and lights, which was the limit of electricity in my Physics O-level.Well, it's "corona" rather than "a corona" or "coronal", but I'm so delighted at someone asking that I'm hardly likely to be fussy about that
It's when the electric field on the surface of the wires, produced by their voltage, is high enough to strip electrons off air molecules or, in the jargon, cause ionisation. Most of the ions thus created recombine almost immediately, a very few escape, but corona is an energy loss and is what causes the occasional audible crackling noise and, rather rarely, radio interference, so it's not a good thing. So we design our lines so that the electric field on the surface of the conductors is below the corona threshold (it's all to do with the radius of the wires and the number and spacing of the 2, 3 or 4 wires in each bundle - more wires is better, which is why you never get single wires at the highest voltages even if you only actually need one for the required current).
But the electric field gets enhanced by any irregularity - the sharper the object the worse - it's the same physics but opposite objective to lightning conductors, which are made pointed in order to attract discharges. So even with an impeccably designed conductor system you will get corona if there are drops of water, or a nice kind farmer has just harvested her field and all the chaff has stuck to the wire.
And that, dear reader, is why power lines crackle more in the wet.
(And I don't know whether to be embarrassed or proud that the bits that stuck out for me in that were the fact that I understood "ionisation" more quickly than "strip electrons", and the fact that "air molecules" caused a bit of a clunk in my brain.
