AC question

Ok, I was watching a doc on electricity, the bloke was explaining that dc currect goes direct but ac currect goes to the load and back to the
generating plant. How is that? When does the load use it then if it goes back to the plant?I thought that ac was a pulse type current. Thanks for any clarification req
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On 2/16/07 1:30 PM, in article snipped-for-privacy@corp.supernews.com, "reqluq"

While I usually am skeptical of analogies, let me offer one. Consider sawing. To cut through a piece of wood, you can use a band saw or circular saw. You could also use a reciprocal saw such as the kind that has a handle on both ends for which is used by two sawyers taking turns pulling the blade. There are also saws that one person can use by pushing and pulling.
The band and circular saws go only in one direction. The other saws I mention go in two directions. The former ones are dc, the latter ones are ac.
Bill -- Fermez le Bush--about two years to go.
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wrote:

I suggest in future you stay skeptical and don't try the analogy thing :-)

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reqluq wrote:

sometimes the old saws are the best.
i guess if we mixed this with the water analogy we would get rust.
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His explanation was really bad. Here is a simplified but more accurate one.
DC current flows in the same direction, at the same magnitude, constantly. AC current varies it's magnitude and alternates direction, typically going through a full cycle from (0 to +MAX to 0 to -MAX to 0) either 50 or 60 times a second depending on where you are located (speaking strictly about power systems).
Electric current does does work (lights a light, produces heat, or rotates a motor) regardless of which direction it flows, or whether it is direct or alternating. Some of the equipment will be different for AC or DC (particularly motors) and transformers only work with AC.
Ben Miller
--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
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Agreed
Not agreed

I'm not qualified to give a response to whether it's accurate or not.

I want to hear: Yes or No; it does/does not go back to the plant, and this is how it does it. I want to know if I lived one light year, or say, an infinity away, and I turned on the light and it took too long to get back to the plant because of the vast distance from the load (if it really goes to the load and back) would that then be in essence DC currect because it's to far to make the cycle back? req
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Current flows in a complete circuit, so regardless of which direction it is flowing, it leaves the generator in one or more lines, and returns in others. So yes, the current goes out and back. However, the current that returns is at a low potential, and can not do any more work. The generator must lift that current to a higher potential before it can go out again.
Current is NOT power. If the current does any work or produces any heat out on the circuit, then that is power that the generator produces, which does not return. It is gone, and your electric meter accumulates it over time (energy), and you pay for it.
Ben Miller
--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
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Probably better to think of it as others have said, the current lows backwards and forwards through the load doing work in either direction.
--
Cheers .......... Rheilly P



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All of the current? you mean none gets used? So on the way back to the plant ( after passing back through the meter) theoretically I could tap into it and get some free currenct? req
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remove the X to answer ----------------------------
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Hey when you explain these things you have to forget using Lysergic Acid Analogy;-) non technical or enigineering savy persona can understand these concepts well as they are.
The bests is Phouls ( shame shame :)
The Generator Pulls and Gives Energy with every Oscilation at the rates Ben mentioned. (electromagnetic ~ mechanical turn)...
So' now I trust you can see how it sends a pulse, that expells and retrieves Electrical Energy from the System.
You see Water going down the drain apparently lost forever too, but it is collected in the Sewer & Drain system - the same is achieved in those Electrical Power AC System, and the Utility Collects it in Billings for now........ (teeheehee)
~ Tick Tock ~
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What the hell is lysergic acid? :-)

Here we go again... where does it *pull* energy from?

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reqluq wrote:

It is really all about extracting energy from somewhere and delivering it in a usable form somewhere else.
Don't get lost in the terms used (easy to do). Take a gasoline engine and hook it to a generator. The gasoline burns, which converts chemical energy to heat energy. The heat energy causes gas to expand - that motion has kinetic energy. That motion spins the generator, and the kinetic energy is converted to electrical energy. Thus someone could say the generator "pulls" energy from the rotation of the engine crankshaft, which in turn "pulls" energy from the expanding gas, which in turn "pulls" energy from the heat produced by the combustion of the gasoline, which in turn had the energy stored in it chemically.
Ed
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reqluq "Tick Tock" wrote in message Hey when you explain these things you have to forget using Lysergic Acid
What the hell is lysergic acid? :-)
DoN't ask' that must be how that all must have started :-D
Analogy;-) non technical or enigineering savy persona can understand these concepts well as they are.
The bests is Phouls ( shamen shame :)
The Generator Pulls and Gives Energy with every Oscilation at the rates
Here we go again... where does it *pull* energy from?
From HERE: when the north & south poles of the magnetic metal in the rotor spin around the non-magnetic electrified metals in the stator.... & proportionally reverse for the windings & metals of The Generator
Ben mentioned. (electromagnetic (Metals with Magnetic Properties PULL )~ mechanical turns (or windings)...!!

So' now I trust you can see how it sends a pulse, that expells and retrieves Electrical Energy from the System. You see Water going down the drain apparently lost forever too, but it is collected in the Sewer & Drain system - the same is achieved in those Electrical Power AC System, and the Utility Collects it in Billings for now........ (teepeemee) ~ Tick Tock ~
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This reminds me of the beginner who, having absorbed the notion that a flow of electric current requires a complete circuit, asked "Why does the electricty company bill me when they get the electricity back again?".
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On 2/17/07 12:45 AM, in article snipped-for-privacy@v33g2000cwv.googlegroups.com, "contrex"

The same is true for water, at least in Los Angeles. You pay for the water and then pay for the sewerage. If you can prove that you do not send the water back, the sewerage charge will be reduced.
Bill -- Fermez le Bush--about two years to go.
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wrote:

Do they really get it back? are you saying it there is no loss when I use my dryer? req
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Yes, there is loss, because the dryer converts the electrical energy into heat energy.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
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Sure the energy is flowing in and out of the power station but it takes applied energy to make it do that. I.e a gas turbine or diesel prime mover etc. thats why there are charges made for you providing a resistance to that flow with your load. Naturally there are losses in transmission and you of course pay for any inefficiencies in your equipment.
--
Cheers .......... Rheilly P.



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