cords coil. Why?

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addams
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cords coil. Why?

Postby addams » Wed Apr 02, 2014 11:00 pm UTC

Electrical Cords Coil.
It is mildly engaging to uncoil the electrical cords.

To uncoil the cord, I usually detach the appliance.
Or; Turn it over and over and over.

Why? I did not turn the appliance over and over and over to coil the cord.
I move it across horizontal space. No summersaults. No juggling of the appliance.

Why do electrical cords coil?
It Can Not be for the same reason plants coil.
Even though the coils look very similar.

http://www.youtube.com/watch?v=Vbzgv5iKEyY
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Re: cords coil. Why?

Postby cyanyoshi » Thu Apr 03, 2014 4:08 am UTC

What kinds of appliances are you talking about? This happens a lot with my home phone a lot, probably because when I pick up the phone to talk and eventually set it back down, I unknowingly turn it a full rotation or two. I've heard that the best way to keep Christmas lights from tangling while in a box is to leave the box alone all year long without touching it. It has to do with random walks or something like that, or maybe the act of disturbing the lights' rest just gets them angry.

If the appliance is being spun around without being picked up, that would have the same effect as picking it up and turning it about the cord. If you don't ever pick up or move an appliance like a toaster, the cord shouldn't really coil at all. Unless of course it does that weird thing that cucumber tendrils do, which might happen if the wire is naturally curly like those aforementioned telephone wires. Maybe electronics just live in a different temporal universe as us, much like plants!

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Re: cords coil. Why?

Postby addams » Thu Apr 03, 2014 4:31 am UTC

Yes. I have been watching sense the last uncoiling.
The cord is rolling as I move across horizontal space.

I had not noticed the complete turns it was making.
Now, I understand uncoiling as a housekeeping task.

If the machine is moved the cord will coil.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

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Those that do not Know; Don't tell them.
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Re: cords coil. Why?

Postby ian » Thu Apr 03, 2014 8:46 pm UTC

Possibly (probably) down the manufacturing process. both the wire and the outer plastic sheath will be stored on spools during and after manufacture. i imagine they coil in the same direction they were on the spools, much like if you roll up a piece of paper and then flatten it out, it will re-roll itself.

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Re: cords coil. Why?

Postby qetzal » Thu Apr 03, 2014 10:00 pm UTC

Maybe the outer plastic sheath changes size over time due to changes in temp, or gradual shrinkage, and that forces coiling?

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Re: cords coil. Why?

Postby stianhat » Fri Apr 04, 2014 8:19 pm UTC

What the other guys said, probably the plastic.

That being said, I have had the pleasure of seeing a watercooled cable explode due to overheating. It was a big one, carrying single phase AC to an induction furnace. I have never even imagined the forces involved when such an event happens - it unwound itself quite violently. electromagnetism is cool.

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Re: cords coil. Why?

Postby addams » Fri Apr 04, 2014 9:35 pm UTC

stianhat wrote:What the other guys said, probably the plastic.

That being said, I have had the pleasure of seeing a watercooled cable explode due to overheating. It was a big one, carrying single phase AC to an induction furnace. I have never even imagined the forces involved when such an event happens - it unwound itself quite violently. electromagnetism is cool.

ok. One more time.
What?
Watercooled cable?
ok. Ok. I can imagine that.
The heat of the umm... cables heat up.

(That makes them nice in the winter.)
How much 'juice' must be running through a cable to require cooling?

What is the diameter of the copper part?
Is a copper alloy still used that way?

What is this? An Induction Furnace?
Inducing What?

I don't really want to know about the machine that pulls that much power.
Do you have a photo on the internet search of this kind of cable?

What does it look like Before?
It uncoiled? It coiled?

It unwound? It was wound?
Was it generating a magnetic field?

Did you want it to do that?
Some people were unpleasantly surprised when they got a magnetic field.

Science is funny.
I like a good, "She Blew." story.

http://www.powercableco.com/induction-m ... ables.html
There is such a thing.

http://en.wikipedia.org/wiki/Induction_furnace
There is such a thing as that, too. It seems.

Why were you watching?
Did you see it?
Or;
Did you hear it and see it later?

Were there Observational Cameras?
The modern world is Wonderful in some ways.

You don't have to guess.
The camera can tell you.

Do you have filters on some cameras?
The flash blinds a camera the same way it blinds a person. right?

But a camera with a filter can see right through the flash.
How cool! Did you take photos?

unwound?
why, wound?

You wound it? Why?
Why not snake it all over the place like other big cords?

Your cord is more interesting than my cord.
My cord was rolling and I did not notice.

Once I started watching, it became obvious.
Why did I not notice, before?

I didn't care what the cord did, as long as it functioned properly.
Getting all coiled up was not functioning properly.

The fault was not with the cord.
The fault was with my expectations.

I am at Peace with the cord, now.
In fact, I like it.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

Those that want to Know; Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

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Re: cords coil. Why?

Postby Neil_Boekend » Wed Apr 16, 2014 11:19 am UTC

addams wrote:
stianhat wrote:What the other guys said, probably the plastic.

That being said, I have had the pleasure of seeing a watercooled cable explode due to overheating. It was a big one, carrying single phase AC to an induction furnace. I have never even imagined the forces involved when such an event happens - it unwound itself quite violently. electromagnetism is cool.

ok. One more time.
What?
Watercooled cable?
ok. Ok. I can imagine that.
The heat of the umm... cables heat up.

(That makes them nice in the winter.)
How much 'juice' must be running through a cable to require cooling?

Induction furnaces easily run into the megawatt domain. The wiki tells me 10KW to 42 MW.
42 MW is a serious amount of energy. I assume the coils have enough resistance to work on 1KV and they are single phase this means there must be 42KA running through the cables.
42KA will melt a AWG 0000 (Ø11.684 mm) in under 1 second. Some quick and dirty calculations and extrapolations tell me it would just about melt a cable of Ø42 mm given enough time.
That is far beyond what I would consider safe. A back of the envelope extrapolation of the rated current for AWG 0000 gives me a safe value of Ø170mm to Ø200mm.
Copper is expensive. If watercooling lets you halve the diameter it saves a lot of money. It does also mean a short can cause the water to boil, which is really really really bad for the cable.
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Re: cords coil. Why?

Postby addams » Wed Apr 16, 2014 3:48 pm UTC

Neil_Boekend wrote:
addams wrote:
stianhat wrote:What the other guys said, probably the plastic.

That being said, I have had the pleasure of seeing a watercooled cable explode due to overheating. It was a big one, carrying single phase AC to an induction furnace. I have never even imagined the forces involved when such an event happens - it unwound itself quite violently. electromagnetism is cool.

ok. One more time.
What?
Watercooled cable?
ok. Ok. I can imagine that.
The heat of the umm... cables heat up.

(That makes them nice in the winter.)
How much 'juice' must be running through a cable to require cooling?

Induction furnaces easily run into the megawatt domain. The wiki tells me 10KW to 42 MW.
42 MW is a serious amount of energy. I assume the coils have enough resistance to work on 1KV and they are single phase this means there must be 42KA running through the cables.
42KA will melt a AWG 0000 (Ø11.684 mm) in under 1 second. Some quick and dirty calculations and extrapolations tell me it would just about melt a cable of Ø42 mm given enough time.
That is far beyond what I would consider safe. A back of the envelope extrapolation of the rated current for AWG 0000 gives me a safe value of Ø170mm to Ø200mm.
Copper is expensive. If watercooling lets you halve the diameter it saves a lot of money. It does also mean a short can cause the water to boil, which is really really really bad for the cable.

That is amazing.
The work of fire being done by electricity.

Mistakes and breakdowns must be impressive.
I can only imagine.

Flashes of Light.
Snapping of Arcs of Electricity.

Booms from the cable sheaths tearing.
Cracks from cables hitting other equipment.

Crashing of balanced shit hitting the floor.
Then suddenly. Nothing.

No light. No noise.
Nothing.

Water, water everywhere and thanking the Gods of Proper Dress for a head lamp to show you the way Out!
I can only imagine. Was the debriefing fun?
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

Those that want to Know; Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

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Re: cords coil. Why?

Postby Izawwlgood » Wed Apr 16, 2014 4:40 pm UTC

Perhaps unrelated, but DNA is coiled and super coiled, and there is a bunch of machinery in place to maintain and work around this coiling. At the very least, it compacts DNA. Additionally, some of the tension from the coiling can drive certain processes. I forget the specifics, but the topology of DNA was a pretty cool chunk of my first year coursework.
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Re: cords coil. Why?

Postby addams » Wed Apr 16, 2014 5:00 pm UTC

Izawwlgood wrote:Perhaps unrelated, but DNA is coiled and super coiled, and there is a bunch of machinery in place to maintain and work around this coiling. At the very least, it compacts DNA. Additionally, some of the tension from the coiling can drive certain processes. I forget the specifics, but the topology of DNA was a pretty cool chunk of my first year coursework.

oh Dear;
I think this Thread is about Macro Coils.
You are typing about Micro Coils.

Similar structures.
Very different functions.

Macro Coils are spectacular when they fail.
Micro Coils are spectacular when they don't fail.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

Those that want to Know; Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

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Re: cords coil. Why?

Postby BlackSails » Thu Apr 17, 2014 11:13 am UTC

Its an entropic effect. There are way more states where the cord is coiled rather than straight. Random disturbances will random walk the chain through its various configurations, and you end up with a coiled cord

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Re: cords coil. Why?

Postby addams » Thu Apr 17, 2014 6:18 pm UTC

BlackSails wrote:Its an entropic effect. There are way more states where the cord is coiled rather than straight. Random disturbances will random walk the chain through its various configurations, and you end up with a coiled cord

Thank goodness someone understands it.
Thank goodness cords work.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

Those that want to Know; Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

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Re: cords coil. Why?

Postby stianhat » Thu Apr 17, 2014 6:43 pm UTC

Neil_Boekend wrote:Induction furnaces easily run into the megawatt domain. The wiki tells me 10KW to 42 MW.
42 MW is a serious amount of energy. I assume the coils have enough resistance to work on 1KV and they are single phase this means there must be 42KA running through the cables.
42KA will melt a AWG 0000 (Ø11.684 mm) in under 1 second. Some quick and dirty calculations and extrapolations tell me it would just about melt a cable of Ø42 mm given enough time.
That is far beyond what I would consider safe. A back of the envelope extrapolation of the rated current for AWG 0000 gives me a safe value of Ø170mm to Ø200mm.
Copper is expensive. If watercooling lets you halve the diameter it saves a lot of money. It does also mean a short can cause the water to boil, which is really really really bad for the cable.


Well, also needed in that back of the envelope extrapolation is the fact that it is single phase AC and that the skin effect is quite substantial in copper. Lets say the frequency is 500 Hz - If you have a copper wire conducting single phase AC, the outermost 2mm of the diametre will be carrying 63% (skin depth = the depth at where the current is X/e where X is defined as the surface value) of the current. If the thickness is over 8mm, the middle part will only see 2% of the load, no matter how thick the cable is... That is why they make them in small cordels, which they wind more of into threads and wind them again to suit the skin depth at working frequency - by distributing them as a hollow cylindre (kinda helix-like) and let water run as coolant in the middle. everything packed in rubber. To avoid loss of coolant and not to mention, short circuits.

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Re: cords coil. Why?

Postby addams » Fri Apr 18, 2014 3:44 am UTC

oh.
Did I understand that?

In copper wire the electron flow is only skin deep?
That explains some stuff I never wondered about.

I assumed there were multiple wires in one cord for weight or something.
No. That is done to allow more elections to flow in the skin of more wire.

ok. Those cords work.
good.

Photos of them failing might be fun.
Life is, just, an exchange of electrons; It is up to us to give it meaning.

We are all in The Gutter.
Some of us see The Gutter.
Some of us see The Stars.
by mr. Oscar Wilde.

Those that want to Know; Know.
Those that do not Know; Don't tell them.
They do terrible things to people that Tell Them.

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Re: cords coil. Why?

Postby Neil_Boekend » Fri Apr 18, 2014 5:11 am UTC

stianhat wrote:
Neil_Boekend wrote:Induction furnaces easily run into the megawatt domain. The wiki tells me 10KW to 42 MW.
42 MW is a serious amount of energy. I assume the coils have enough resistance to work on 1KV and they are single phase this means there must be 42KA running through the cables.
42KA will melt a AWG 0000 (Ø11.684 mm) in under 1 second. Some quick and dirty calculations and extrapolations tell me it would just about melt a cable of Ø42 mm given enough time.
That is far beyond what I would consider safe. A back of the envelope extrapolation of the rated current for AWG 0000 gives me a safe value of Ø170mm to Ø200mm.
Copper is expensive. If watercooling lets you halve the diameter it saves a lot of money. It does also mean a short can cause the water to boil, which is really really really bad for the cable.


Well, also needed in that back of the envelope extrapolation is the fact that it is single phase AC and that the skin effect is quite substantial in copper. Lets say the frequency is 500 Hz - If you have a copper wire conducting single phase AC, the outermost 2mm of the diametre will be carrying 63% (skin depth = the depth at where the current is X/e where X is defined as the surface value) of the current. If the thickness is over 8mm, the middle part will only see 2% of the load, no matter how thick the cable is... That is why they make them in small cordels, which they wind more of into threads and wind them again to suit the skin depth at working frequency - by distributing them as a hollow cylindre (kinda helix-like) and let water run as coolant in the middle. everything packed in rubber. To avoid loss of coolant and not to mention, short circuits.

The skin effect is one of the reasons multicore cables are used. A single copper tube isn't flexible and thus a b*tch to install.
To adams: skin effect is only applicable in AC applications. DC uses the complete cable. The skin depth decreases with increasing frequency. Usually the way to get around it is by using a lot of thin cables instead of one thick one. As it turns out these thin cables don't have to be isolated from each other so most flexible cables work.
At the 50 or 60 hz of a normal outlet the issue is usually ignored because it is so small.
Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

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