AC Current Flow Question

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AC Current Flow Question

  • 100 milli-Amps

    Votes: 0 0.0%
  • 80 milli-Amps

    Votes: 3 9.7%
  • 60 milli-Amps

    Votes: 23 74.2%
  • 40 milli-Amps

    Votes: 1 3.2%
  • 20 milli-Amps

    Votes: 0 0.0%
  • 0 milli-Amps

    Votes: 4 12.9%

  • Total voters
    31
  • Poll closed .
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crossman

Senior Member
Location
Southeast Texas
Gentlemen:

This question and poll arises from another thread. I would appreciate your vote and any responses. Thank you.

An AC source feeds a xfmr. The secondary produces a high voltage. The two ammeters are calibrated properly. A conducting body is suspended in air and is perfectly insulated from earth. One lead of the secondary is attached to Ammeter 1 and Ammeter 1 is attached to the conducting body. The other lead of the secondary is attached to Ammeter 2 and Ammeter 2 is attached to earth.

Ammeter 1 reads 60 milliamps.

Question: What amperage does ammeter 2 show?

highv.jpg
 

zog

Senior Member
Location
Charlotte, NC
I dont have an exact answer for you but they will not be the same. I tried this with a 5kV megger by comparing leakage current (Calculated) gaurded and ungaurded. Gaurded values were about 40% less the ungaurded.

I would rather do this wih my 100kV hipot (Or even 50kV) but they dont have a gaurd circuit and I dont have any ammeters I want to fry.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
The only reason current can flow at all is that there will be capacitive and inductive coupling between the conducting body and planet Earth. But whatever else is involved in the path for current flow, the two ammeters are in series. They can not have different currents passing through them.
 

drbond24

Senior Member
I'm with Charlie. The current flowing through the loop is the same all the way around the loop. If meter 1 is somehow reading 60 mA, then so is meter 2.

In addition, I would have to say that unless you draw in an arc from the conductive body to earth, you don't have any current flow at all. :smile:
 

zog

Senior Member
Location
Charlotte, NC
This post is being taken out of context, please read posts 1-334 of "current retuning to a different source" thread.

I did this test in my lab today and the results dont lie, dont believe everything George Simon Ohm believed.
 

crossman

Senior Member
Location
Southeast Texas
The theoretical question posed in the OP is valid. We are assuming perfect conditions, the diagram implies a certain symmetry in the placement of wires and components. There is nothing out of context in this question. The laws of physics and electricity do not care anything about any thread that was ever debated on the internet.
 

zog

Senior Member
Location
Charlotte, NC
crossman said:
The theoretical question posed in the OP is valid. We are assuming perfect conditions, the diagram implies a certain symmetry in the placement of wires and components. There is nothing out of context in this question. The laws of physics and electricity do not care anything about any thread that was ever debated on the internet.

This is not a simple Ohms law question, now you have people just saying 60mA because thats what they think, no proof, field experience, or lab experiments.

I am not taking part in this thread anymore, see you in the "Current returning to a different source" thread where we can continue this discussion.
 

nakulak

Senior Member
The coil is a node unless I'm missing something the currents must be the same ? (I could see where if the voltage was high enough that an ionizing current could bypass the coil, but otherwise I would expect the currents to adhere to Kirchoff's law ?)
 

rattus

Senior Member
Correct:

Correct:

charlie b said:
The only reason current can flow at all is that there will be capacitive and inductive coupling between the conducting body and planet Earth. But whatever else is involved in the path for current flow, the two ammeters are in series. They can not have different currents passing through them.

For the circuit as drawn, there would be zero current. If we add the stray capacitances, we might see a difference depending on the location of the ammeters.
 

Rick Christopherson

Senior Member
zog said:
This post is being taken out of context, please read posts 1-334 of "current retuning to a different source" thread.

I did this test in my lab today and the results dont lie, dont believe everything George Simon Ohm believed.
This situation does not violate either Ohm's Law, nor Kirchoff's Rules. Unfortunately, the people that believe it does, do not know the full context of those Laws and Rules.

I'm with you--I am not going to participate in this thread any further since this topic is already active in another thread, and the intent here is to take it out of context with the original situation.

Shame on you Crossman. You didn't like the answers you were getting in the native thread, so you started this one in hopes of getting answers that fit your ideals?:-?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
The only way it could read anything other than 60ma is if at least one of the meters is being bypassed.
 

crossman

Senior Member
Location
Southeast Texas
Rick Christopherson said:
I am not going to participate in this thread any further since this topic is already active in another thread, and the intent here is to take it out of context with the original situation.

Shame on you Crossman.

The laws of physics and electrical phenomena do not change from one thread to another. This is a valid question to ask regardless of where it is posted. There is no "context" to be considered.

Not that I owe anyone an explanation - but - I contacted a moderator asking him if I could post a poll concerning a topic in an existing thread. I did this before I started this thread. He told me that starting a new thread with a poll is a great idea because many times existing threads are cluttered with so many different thoughts that it becomes difficult to follow. So if I have upset you, I apologize from the deepest depths of my heart.

Now, back to some electrical theory....

P.S. Did you vote?
 

coulter

Senior Member
Nope - didn't vote.

I don't think its a bad question. It's a question about a mathematical model. Like all models, one has to apply the boundary conditions. charley b's were pretty good. Two conductive bodies separated by an insulator is a capacitor. The other boundry charlie applied (my translation of his post anyway) is no extranoeus, unseen leakage. Apply an AC voltage to the cap plates and current flows.

As I recall, Norton was the one that said the current entering a node equals the current leaving the node. As plenty of others have already said, if one ammeter reads 60ma then any other ammeter in the series loop will read 60ma.

zog said:
...I did this test in my lab today and the results dont lie, dont believe everything George Simon Ohm believed...
zog -
I hope your results are lying - I hope there are some unseen phenomena giving bad data. But then again, if not, we will be seeing your name in some pretty prestigous journals soon - and that's okay too.

Assuming "George Simon" is the Mr Ohm, yeah I believe everything he wrote in his second paper (he had it wrong in the first paper)

carl
 

coulter

Senior Member
Just out of curiousity:
If the 334 post count thread were stripped of all arrogance, demeaning remarks, out of context inuendo, and only contained non-repetitive science/physics, how long would it be?

If crossman wants one devoid of the junk, what's wrong with that?

And if you (plural) don't want to participate, what's wrong with that?

carl
 

coulter

Senior Member
crossman said:
... why not go ahead and vote?
Cause the majority will not rule here. This is a math model discussion. Opinion really doesn't matter.

The only thing I can think of is those who don't agree are using a different set of boundry conditions/model limitations. The only poor part is not being clear about one's assumptions.

carl
 
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