current returning to a different source

[crossman]

Rattus, I agree with you on all points.

Explanation of my thinking: As for the capacitor, if we want to consider that it is not a voltage source, that is okay with me. I had always thought of a charged capacitor as a voltage source. I concede that a capacitor does not "create" a voltage difference like a battery or generator. However, if we connect one side of a resistor to a charged capacitor, and the other side of the resistor to the other side of the capacitor, in my mind this is a completed path. In my mind, I would even call it a completed circuit. Perhaps "technically" it is not a "circuit" but it is certainly a completed path as for Ohm's Law. I know that you understand all this already.

As for the copter, I totally agree with you. .

 

[rattus]

Spin:

Spin:

Nonsense. I have not said there is no capacitance between the power lines and earth. I believe capacitance exists between any two bodies of mass, all the way down to the atomic, perhaps sub-atomic level. So should we include the effects of capacitance in all our electrical discussions? I think not. When in cases where specific capacitance effects contribute nothing to the situation, they can rightfully be ignored. I claim, in this case, the effect of capacitance between the power lines and earth are negligible.

Let me repeat myself:

First, you have no numbers to justify your assumption that line to ground capacitance is neglible especially when you consider the added area of the copter to the equation.

Second, even if you ignore the line to earth capacitance, you still have the line-copter-line capacitance which can account for the arc current by itself. Surely you con't claim we can ignore that current.

Clearly, the arc current is capacitive. Claiming otherwise is like jousting with windmills.

 

[Rick Christopherson]

Clearly, the arc current is capacitive. Claiming otherwise is like jousting with windmills.

If it was so clear, then why would we be having this discussion? Throughout this entire discussion, no one has come forward and said, ?your theory won?t work, and here is the reason it won?t work....?

You say that what I?ve presented is ?heresy? or ?jousting with windmills?, and yet you have not been able to give any reason why this information is incorrect. If my theory is so flawed, it should be easy for you to find that flaw.

By the way, if all of these capacitances existed to the degree that you claim, then why wouldn?t a helicopter hovering 1 foot off the ground below the power line experience arcing with the ground. It is still in the middle of a capacitive circuit, isn't it?

 

[crossman]

Part of the answer lies in the response to my question concerning the two capacitors with the switch between them. I would appreciate your thoughts on what happens when the switch closes.

As for the helicopter close to the ground and under the powerlines, who says there won't be some current flow when the copter touches down? Who says there wouldn't be an arc if we held the electrode in close proximity to the earth?

 

[Rick Christopherson]

As for the helicopter close to the ground and under the powerlines, who says there won't be some current flow when the copter touches down? Who says there wouldn't be an arc if we held the electrode in close proximity to the earth?

Then a vehicle driving under the line with rubber tires would arc from the chassis to the ground.

When you close the switch, you get a charge transfer. EDIT: (Hmm, I typed before I thought. I hadn't looked close enough at it.)

 

[crossman]

Then a vehicle driving under the line with rubber tires would arc from the chassis to the ground.

That is a good point. Let me think on that one!:smile:

When you close the switch, you get a charge transfer.

While I am thinking on the vehicle/powerline - Could you be more specific on the charge transfer? There are 1000 positives on cap 1 connected to 5000 electrons on cap 2. Care to estimate how many would be transferred and to where?

 

[rattus]

OK then:

OK then:

If it was so clear, then why would we be having this discussion? Throughout this entire discussion, no one has come forward and said, “your theory won’t work, and here is the reason it won’t work....”

You say that what I’ve presented is “heresy” or “jousting with windmills”, and yet you have not been able to give any reason why this information is incorrect. If my theory is so flawed, it should be easy for you to find that flaw.

By the way, if all of these capacitances existed to the degree that you claim, then why wouldn’t a helicopter hovering 1 foot off the ground below the power line experience arcing with the ground. It is still in the middle of a capacitive circuit, isn't it?

OK, your theory will not work because it is not founded on fact. We are having this discussion because you are either stonewalling or do not understand AC circuits. You refuse to admit the caps are there.

You have it backwards. You have presented the theory, it is incumbent on you to prove it.

There would be no arc near the ground because the field is much weaker near the ground. Now if we flew the copter between the wires we might get an arc from both sides which would effectively short the two lines and melt the copter!

Why don't you disprove my analysis which is based on well known methods?? Steady state circuit analysis that is. Can you?

 

[Rick Christopherson]

Could you be more specific on the charge transfer?

After looking at it again, I don't believe anything will happen when the switch closes.

 

[crossman]

There would be no arc near the ground because the field is much weaker near the ground.

That makes sense to me Rattus. Thanks for clearing that up. The charge on the earth is going to be spread out over a larger area than the charge concentrated in the wire. An object near the ground is not going to experience anywhere near the elctrostatic field as compared to an object near the wire.

 

[rattus]

Rick is right!

Rick is right!

After looking at it again, I don't believe anything will happen when the switch closes.

Correct! Because there is no complete path! But, you don't sound very sure of your answer.

 

[rattus]

Rattus, I agree with you on all points.

Explanation of my thinking: As for the capacitor, if we want to consider that it is not a voltage source, that is okay with me. I had always thought of a charged capacitor as a voltage source. I concede that a capacitor does not "create" a voltage difference like a battery or generator. However, if we connect one side of a resistor to a charged capacitor, and the other side of the resistor to the other side of the capacitor, in my mind this is a completed path. In my mind, I would even call it a completed circuit. Perhaps "technically" it is not a "circuit" but it is certainly a completed path as for Ohm's Law. I know that you understand all this already.

As for the copter, I totally agree with you. .

We could consider a cap to be a charge source, and I think calling it a transient voltage source is not out of the question.

 

[crossman]

After looking at it again, I don't believe anything will happen when the switch closes.

Okay, now we are getting somewhere. Why won't the electrons move when the switch closes?

"Electrons do not have sir-names or home addresses. They don't care if they ever return home or not. All they care about is that they move from a negative voltage to a positive voltage. They don't care whether the positive voltage comes from one source and the negative voltage is from a different source."

I am certain that each of us is interested in the truth of the matter. This is not a debate.:smile:

 

[Rick Christopherson]

Okay, now we are getting somewhere. Why won't the electrons move when the switch closes?

They won't move because they are being held in place by the opposing charges on the opposite plate within each capacitor. You're gloating as though this was some sort of coup, but it doesn't apply to the problem. Have you forgotten that capacitors was your supposition, not mine?

 

[crossman]

That I am "gloating" is an assumption. I seek the truth. And I feel I am making progress.

 

[Rick Christopherson]

If this problem was the simple circuit analysis of a few capacitors that you keep professing, then why has it taken two weeks to solve a simple circuit problem? Draw a few caps, voltage sources, phasor diagrams, and you're done, right?

You've calculated the capacitances, so what is the current flow through the probe given your circuit analysis?

 

[crossman]

The simplified circuit has already been drawn. Winnie has already done the calculations and he has estimated that 60 mA from copter to wire would be in the ballpark. I have no reason to disagree with his conclusion. For me, the simplified circuit involving capacitance is a satisfactory mechansim for the phenomenon.

However, I am always seeking new knowledge and when someone professes they have knowledge of a process I am unaware of, I become interested. I want that knowledge too. The reason we have been discussing this for two weeks is because I am a skeptic and I am not going to believe in anything new until there is convincing evidence that I should believe it.

If you could give some evidence that I could verify from other sources such as a Physics Text or a college physics department website then I would be extremely happy. I would be happy because I would have gained a greater understanding of the subject.

 

[Rick Christopherson]

The simplified circuit has already been drawn. Winnie has already done the calculations and he has estimated that 60 mA from copter to wire would be in the ballpark.

Well that's interesting. It takes 20,320 volts per inch to ionize air at STP. The helicopter is hovering with the probe about 6 inches from the line (see the video). This means that the voltage difference between the helicopter and the line is greater than or equal to 122,000 volts. Ionized air has nearly all of its free electrons stripped away, and as a result, it has an extremely low resistance, on the order of an electrical conductor.

So without violating Ohm's law (which still applies, by the way) how can you have 122,000 volts across a conductor, and only have 60 mA?

Proving that some capacitance exists between the helicopter and the earth, and/or the helicopter and other lines, does not disprove my theory. Moreover, the capacitance presumption does not support the large current flow.

 

[Rick Christopherson]

If you could give some evidence that I could verify from other sources such as a Physics Text or a college physics department website then I would be extremely happy.

I would be happy to discuss the physics of this situation more, but you and rattus keep pulling it back toward capacitors and standard circuit analysis. You say you are open minded and want to learn, but you keep pulling the discussion away from the physics where it is based. I've lost count how many times I have stated that you need to stop looking at this from a circuit analysis problem and look at it from a physics perspective. Until you are able to set aside your existing predispositions and look at this from another perspective, you will never come to an answer.

 

[rattus]

Six years of college wasted!

Six years of college wasted!

I would be happy to discuss the physics of this situation more, but you and rattus keep pulling it back toward capacitors and standard circuit analysis. You say you are open minded and want to learn, but you keep pulling the discussion away from the physics where it is based. I've lost count how many times I have stated that you need to stop looking at this from a circuit analysis problem and look at it from a physics perspective. Until you are able to set aside your existing predispositions and look at this from another perspective, you will never come to an answer.

Rick, I don't think you have the credentials to tell anyone else how to solve a problem, and I see no evidence that you understand AC Circuits. If you did, you would see a valid solution, and you would realize that using a different method would not change the outcome. Other statements from you lead me to believe you aren't a whiz at Physics either.

Other learned members of the Forum have explained the arc as a capacitive current, so why do you flounder on by suggesting we are doing it wrong? Truth is, you have come up with a hare-brained idea, not even a theory, which you can't explain, yet you maintain we are wrong??

Something is wrong here, and it is not our straightforward explanation!

You yourself have said that a current will flow if we have a voltage and a path. We have both, and the path is two caps in series. Dog simple! Be a man; admit that we are right!

 

[crossman]

Well that's interesting. It takes 20,320 volts per inch to ionize air at STP. The helicopter is hovering with the probe about 6 inches from the line (see the video). This means that the voltage difference between the helicopter and the line is greater than or equal to 122,000 volts. Ionized air has nearly all of its free electrons stripped away, and as a result, it has an extremely low resistance, on the order of an electrical conductor.

Very interesting indeed! And hopefully I get to learn something new. I admit I know very little about current flow through air. But, I will go out on a limb with some specualtion, which may very well be wrong.

As for 20 KV per inch required to ionize air - I have played around with a neon light xfmr that went from 120 volts to 5000 volts. This transformer secondary would cause an arc across an approximately 1" air gap. So either the 20 KV figure is high, or, complete ionization is not necessary for current flow through air. Do you have a link to any info on the subject or where the 20kV figure came from? I seem to remember from somewhere else that less than 2000 volts could cause a spark across a 10mm gap.

As for the impedance of the air, again, I know very little. On one hand it would seem the impedance would be very low as you mention, but the fact that a spark creates a very high heat output tells me that a lot of energy is being dissipated across a resistance. If the air was an "extremely good conductor" like a copper wire, then shouldn't the spark be near ambient temperature? What makes it get hot other than "friction" of the resistance? Something is causing the heat loss, which is a loss of energy of the current flow, and must be caused by something other than an "extremely good conductor".

So without violating Ohm's law (which still applies, by the way) how can you have 122,000 volts across a conductor, and only have 60 mA?

I am guessing there are some flaws in the "122,000 volts" and "conductor". Regardless, this point applies to both the capacitor explanation and your explanation of the helicopter phenomenon.

Proving that some capacitance exists between the helicopter and the earth, and/or the helicopter and other lines, does not disprove my theory. Moreover, the capacitance presumption does not support the large current flow.

In your explanation of the helicopter phenomenon, what level of current do you suspect is flowing between wire and copter?