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Batteryless current clamps?

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Jim Thompson is notoriously enthusiastic about plonking people he disagrees with. Someone who took him seriously might be upset by it. This strikes me as information that Proteus IIV might find useful.

If I felt like heaping abuse on Jim Thompson I'd be more explicit about it.

The image of the incorrigibly offensive John Fields ever being put on the defensive is amusing. Not as amusing as the idea that you might ever have consulted a text-book, but distinctly comical all the same.

But we can rely on you for seriously side-splitting - if unintentional

- comedy. The clown who still thinks that the 555 is the answer to every circuit problem imagines that he can call somebody else a fatuous ass.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman
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Since the original claim was

" >Wrapping some turns around the power company's lines will get you many, many

This isn't the reason - lines is plural and the nett current through the lines as a bunch balances out to zero.

Wrapping a clamp-on meter around one line means that there is current circulating around the clamp - the current that goes through the selected line in one direction is matched by equal and opposite current flowi g through the other lines in the other direction. The coupling coefficient is unlikely to be good, but it is finite.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

al

If one can rely on that "passive". Someone who knew a little more than you might extract some of the power circulating through the wire and produce an active solution without an external power source.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

FINALLY an answer on-topic. Thank you.

After watching the 3 Stooges act that is aee / sed...

Sheesh!

I AM FBt

Reply to
Fester Bestertester

Admitted that the S/N ratio on Usenet can be frustrating. But did you stop to consider the possibility that a) you failed to grasp other attempts to explain it to you; b) your question was so elementary for *this* group that few people bothered; c) your last post might be taken as a slap in the face by those who tried to help.

Reply to
Pointless Posts 

--
Since that's obvious to the most casual observer, the context of his
statement must have been about wrapping some turns around [one] of the
power company's lines, which I addressed by referring to it as "the
power line".
Reply to
John Fields 

--
Bullshit, liar.

What you were doing was telling P3 to clean up his act or you'd plonk
him, and then, out of the blue, you just _had_ to take another little
snipe at Jim.

I guess you just can't get over his reporting you to the FBI, huh?
Reply to
John Fields 

--
Can't come up with anything, huh?  What a surprise!!!
Reply to
John Fields

Right you are.

A big thank you to those responders who gave answers to my question. Much appreciated.

My comment was addressed to the "noise". :-)

FBt

Reply to
Fester Bestertester

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elf.

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I don't plonk anybody, and I certainly wasn't threatening that I'd plonk him

If he'd known how much pleasure I was going to get out of pointing how how seriously far out of touch with reality that proved him to be, he probably wouldn't have done it. I know he is conscious of his duty to protect his country, but it isn't as if he is fanatical about it.

Even you will have to admit it has to be the funniest prat-fall we've ever had around here.

k

Nice to see you sending yourself up from time to time. There have been times when I've imagined that you lack a sense of humour, but that really is funny. Nice one.

e

Or any more. Your judgement isn't all that great outside of electronics either.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

...

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Nice try.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

field

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robe

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You asked about the Fluke i200s current clamp probe. I've never used one, and I'm not sure that I've even seen one, which discouraged me from trying to improvise an explanation.

John Field's response - now that he has finally got around to making the kind of useful post that he claims to represent the bulk of his output - does seem to be plausible.

From time to time we get responses from the people who designed the gear under discussion, but you don't seem to have been that lucky.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

Yes. Classic AC clamp-on ammeters are simply transformers. One "turn" through the clamp, many turns in the fixed coil for output. The output feeds into a voltmeter.

Those are AC-only devices. There are also Hall-effect clamp-on ammeters, and those work for both AC and DC. These have been available for a decade or so, and pricing is now down as low as $60. I used to have one that could read down to about 500mA DC, and it only cost $129. Very useful in robotics and controls work.

John Nagle

Reply to
John Nagle
[...]

Which make & model would that $129 model be? It's always useful to know someone else's favorite tools...

Dave

Reply to
DaveC

? "Fester Bestertester" ?????? ??? ?????? news: snipped-for-privacy@news.eternal-september.org...

There's nothing fancy about that, the electricity meters of a medium-voltage consumer (real and reactive energy) are powered from the two potential and the two current transformers, without any other power supply (medium voltage=15 kV in Crete).

--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr
Reply to
Tzortzakakis Dimitrios 

--
Of course, you fraud, since by snipping the rest you sidestep the issue,
which is your ignorance in believing that a solenoid wound around an
alternating current carrying conductor can be used to extract power from
the varying magnetic field surrounding that conductor.

Nothing could be further from the truth, as demonstrated here:

news:26iag5hjpub42ookl0nk74vc3ffgs7316q@4ax.com

Since, conveniently, you don't have access to abse, I'll take the
liberty of emailing you the photos as soon as I post this.

Enjoy. :-)

JF
Reply to
John Fields

So, for a millivolt output probe, this might be as simple as 2 windings (or a tapped single winding) with a range switch to select the winding?

Reply to
Fester Bestertester

Current transformers are usually dumped into a load resistor aka burden resistor, to convert their output current into voltage. I'm sure the Fluke clamp-on has an internal burden resistor, and they may switch that to change ranges.

Without a burden resistor, the output voltage will be proportional to frequency and very dependent on core reluctance, which would be fatal for a clamp-on meter with a hinge and a non-repeatable air gap.

Coreless Rogowsky coils are used unloaded, but need a downstream integrator to accurately measure current.

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The coolest current transformer is a second-harmonic DCCT, accurate to parts-per-million from DC to many kilohertz.

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John

Reply to
John Larkin

(or a

Wiki's great thanks John. That second link didn't have much info on how the device works. Is the following the same thing?

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(I googled second-harmonic DCCT)

George H.

Reply to
George Herold

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-Hi...

ever

Your enthusiasm for inventing implausible straw men knows no bounds. I never made any such claim. My scepticism about you claim was purely based on the fact that you were ignoring what Joel Koltner had actually said.

The pictures were perfectly clear. It was less obvious what you were actually doing, but since I couldn't care less, this isn't any great loss.

The joke is that even if you do extract "many watts" from the power company's power lines, you won't be stealing from them. In order to be able to extract power you have to be drawing power for which you will be billed, and any extra watts you extract by transformer action is subtracted from the power you are already paying for - your paid for load will be seeing a lower drive voltage.

Joel Koltner made a rather good joke, which you have totally failed to get.

-- Bill Sloman, Nijmegen

Reply to
Bill Sloman

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