ECN Forum
Posted By: sparky66wv Flamed and need reassurance - 09/15/02 02:55 AM
http://forums.fark.com/cgi/fark/comments.pl?IDLink=299650&ok=true

If the link works, I'm sparky66wv there too...

Some dude named Argile and myself disagree toward the bottom of the thread.


[This message has been edited by sparky66wv (edited 09-14-2002).]
Posted By: Redsy Re: Flamed and need reassurance - 09/15/02 03:14 AM
sparky,

10 millivolts wouldn't push enough current through a wet noodle to allow 100 milliamps to flow. Regardless of the KVA rating.
You are right, sir.
Posted By: stamcon Re: Flamed and need reassurance - 09/15/02 03:24 AM
Sparky, what the fark are you doing at that site? It's frustrating sometimes, that you can't reach your arms out someone's monitor and shake the fark out of them. I wonder what Argile's career in the electrical field is? I think he's out in left field.
Posted By: caselec Re: Flamed and need reassurance - 09/15/02 03:31 AM
Why don't you ask Argile to come over here to continue the discussion. We will be glad to help you straighten him out.

Curt
Posted By: George Corron Re: Flamed and need reassurance - 09/15/02 03:38 AM
Sparky66wv,
DOOOOOOOOOOD, I love ya man, see what happens when you argue with an idiot? NOW you see why I stay away from DIY forums and the argument? The guy obviously knows enough to injure himself, and, IF WE'RE LUCKY, will remove himself from the gene pool and deprive us of his vast knowledge.

Of course you're right, now stay away from ding bats. [Linked Image]
Posted By: DaveB.inVa Re: Flamed and need reassurance - 09/15/02 03:55 AM
Your right Sparky.

Throw a little bit of ohms law in your reply. This guy does have some stuff correct but the way I take it he thinks that a 10mV transformer is going to always put out its rated current no matter what the resistance.

There is his fatal flaw, he does not realize that even though the current does kill it requires a certain voltage to pass it through a certain resistance in your body.

Argile,
If you read this understand that typical human resistance values range from a few hundred ohms to thousands of ohms, typical values are stated to be in the 800-1000 ohm range.

If a human had a resistance as low as 500 ohms with 120v applied to the person simple ohms law will dictate that 240 milliamps will flow and could prove fatal.

With the same resistance (500 ohms) and 10mV only 20 microamps will flow. This wouldnt even be felt by most and I would not hesitate to play with it all day long no matter the KVA rating of the transformer.

BTW to get your bodys resistance down low enough that 10mA were to flow with 10mV you would have a pathetic and unrealistic 1 ohm.

Can you imagine a 1KVA 10mV transformer!! That puppy would be a hoss!! Even a 1VA 10mV transformer would be pretty large.
Posted By: sparky66wv Re: Flamed and need reassurance - 09/15/02 04:04 AM
Thanks guys, he almost had me convinced that I didn't know what I was talking about!

[Linked Image]

George, I used you as a sledge hammer again...

(Hope you don't mind)

[This message has been edited by sparky66wv (edited 09-15-2002).]
Posted By: Argile Re: Flamed and need reassurance - 09/15/02 04:22 AM
Ok i'm confused then...makes sense after a discussion that long and many points thrown out. [Linked Image] Yes i understand how ohms law works and that 1v shouldnt kill you, but in the same respect (this is pretty much what i was arguing on), how is it that people can have situations setup of extremely high voltage (like 10,000 volts), but low current with their body's resistance?
Posted By: sparky66wv Re: Flamed and need reassurance - 09/15/02 04:29 AM
Welcome to ECN, Argile.

In the situation where large voltages with low current not causing harm, the circuit is limited either by the VA rating of the Xformer, or a resistor in line, otherwise the current would only be limited by the resistance of your body.

Electric Fences are a good example here.

The inverse is not true! Just because an Xformer has large current capacity, doesn't mean the circuit will "call" for all 100%. The current will flow according to the resistance, the voltage, and up to the available current limit.
Posted By: sparky66wv Re: Flamed and need reassurance - 09/15/02 04:31 AM
BTW, we have an international section too.
Posted By: Argile Re: Flamed and need reassurance - 09/15/02 04:33 AM
right i understand that, but what i'm saying is, i know 120v can kill you, so why is it that we did this experiment in one of my classes where the teacher used a transformer to give us a jolt (using dc...collapsing field) with insanely high voltages and none of us died or were even burned?
Posted By: sparky66wv Re: Flamed and need reassurance - 09/15/02 04:39 AM
I admittedly, will have to let one of my buddies here answer that one...

(Read: got me?)

But I will guess that the current was limited in some way, either by resistance or by time.

Where's Pauluk or Scott35 when ya need 'em?

[Linked Image]
Posted By: Argile Re: Flamed and need reassurance - 09/15/02 04:42 AM
thanks sparky, but i wont be sticking around...i feel stupid missing hte simplicity of ohm's law smile It just confused the crap out of me how people can be hit with large voltages with transformers involved and live (and often done in demonstrations relating to transformers) yet you can be killed by 120v. Also i know how in power transmission they increase voltage which decreases current so they can use smaller wires...then when it's back at the distrobution transformers, they do the opposite, so why couldnt they just keep decreasing voltage (which would thereby increase current, following that same logic) and have a large amount of current? Confusing confusing smile (even as you mentioned, it had you confused for a minute too =)
Posted By: sparky66wv Re: Flamed and need reassurance - 09/15/02 04:46 AM
It is limited by the cost of the larger wires required to carry the current.

It is always a trade-off.

Higher voltages are limited to dielectric strength of the insulators, high current to the limit of cost of large conductors.

Voltage Drop would also cause problems, especially with the heating due to resistance which causes the resistance to rise and creates a viscious cycle.

I bid farewell to you Argile, stop back in sometime.

[Linked Image]


[This message has been edited by sparky66wv (edited 09-15-2002).]
Posted By: frank Re: Flamed and need reassurance - 09/15/02 05:02 AM
Actually in hospitals, O.R line isolation monitors are factory calibrated to go into full alarm at 2ma because any thing over 8ma can send a heart into defib depending on the voltage and resistance right?

[This message has been edited by frank (edited 09-15-2002).]

[This message has been edited by frank (edited 09-15-2002).]
Posted By: pauluk Re: Flamed and need reassurance - 09/15/02 08:50 AM
Somebody call me? [Linked Image] That danged 5-hour time difference means I get to miss all the excitement again! [Linked Image]

Argile,
Allow me to quote from one of your posts:
Quote
If a transformer is used to increase the voltage, the current decreases. Also the same goes if you just flip the transformer around (so that the input windings are now the output windings)...your voltage is going to decrease and your current is going to increase. Therefore if you have a transformer that can lower the 120v in the wall to 10mV, that's going to create a ***** load of current...there's no way you'd be grabbing ahold of that and just "feeling a tingle". In fact, you probably wouldnt feel anything, because you'd be dead.

Your basic theory that if you decrease the voltage you simultaneously increase the current holds true for comparing the primary and secondary of a transformer delivering a specified amount of power to a load.

Example: Suppose you had a 60W 6V bulb run from a 120V outlet via a step-down xfmr. The secondary current in the bulb would be:

I = P / E = 60 / 6 = 10A.

The primary current on the 120V side (ignoring xfmr losses) would be:

I = P / E = 60 / 120 = 0.5A.

Would I put my fingers directly across the 6V secondary terminals, even though the current flowing there is 10 amps? Yes, without hesitation. Would I do the same on the primary side? No, not even if the primary xfmr current were only 1mA.

The 10A of secondary current is flowing due to the low resistance of the bulb. A 60W 6V bulb would have a filament resistance of only 0.6 ohm.

If I put one hand on each terminal of the xfmr secondary, that doesn't mean that 10A would flow through my body. I would be creating a parallel path. The bulb would still be drawing 10A, but the current going through me would be limited by my body resistance. If my hand-to-hand resistance were, say, 10K ohms, the current through me would be just 0.6mA. The fact that 10A is flowing in the rest of the circuit is irrelevant -- Ohm's Law will dictate the current through my body based on the applied voltage and my body resistance.

If I were to touch the 120V primary terminals with the same 10K body resistance, the current would be much higher: 120/10K = 12mA.

Taking your example of stepping down the voltage to 10mV, yes, if it were to provide any reasonable amount of power the current would be massive. If you could have a 60W 10mV bulb it would draw 6000 amps! (Boy, that would be some transformer! [Linked Image])

But if I touched the 10mV secondary terminals I wouldn't feel a thing. With the same 10K body resistance, the current through me would be just 1uA (that's 1 microamp, or 0.000001A), even though there might be 6000A flowing through the circuit.

Virgil,
The collapsing field experiment has two things to consider. First, disconnecting DC from the primary causes a pulse of secondary current of very short duration. (Think automotive ignition coil.) Second, it's quite likely that the coil used had a very high turns ratio and the secondary winding would have an appreciable amount of resistance to limit the current.

The electric fence controller is a good example. The open-circuit voltage of each pulse may well reach a couple of thousand volts or more. But it's fed from a relatively high-impedance source which will severely limit the available current. When you grab hold of the wire, your body resistance to ground forms a potential divider with that source impedance so that the voltage to ground actually appearing on the wire (and across you!) is then much, much lower.

Another example of a high-voltage with a high-Z source is the final anode supply to the tube in your TV (or computer monitor). Even on a small tube, the final anode can run on 10kV or more, and for a big-screen color set it's easily in excess of 30kV. However, the source (in all modern sets) is a winding on the line-output xfmr and a voltage multiplier chain. The overall source impedance is very high, in the order of many megohms, so the current is severely limited, e.g. 15kV with source Z of 10 MEG = max. current of 1.5mA. You can draw sparks from the HT lead, and get fantastic blue corona displays around the tube connector in a darkened room, but there are many TV techs who have touched it and lived to tell the tale. (Probably a little cursing was heard.... [Linked Image])

In old tube-type TVs a far more dangerous jolt could be had from the line sweep boost rectifier, typically 500 to 800V with an available current of several tens of milliamps.



[This message has been edited by pauluk (edited 09-15-2002).]
Posted By: sparky Re: Flamed and need reassurance - 09/15/02 11:46 AM
Another angle....

there is a strong Telsa following, with many pages on the 'net.

they like to fark with higher voltages....

Apparently one can jack up the frequency so as to have 99% 'skin effect' resulting in a flow around more than through conductables

I wish i had bookmarked the particular individual whom ,operative to the latter, had posted himself with lightning bolts appearing from his pointed finger....
[Linked Image]
Posted By: George Corron Re: Flamed and need reassurance - 09/15/02 12:34 PM
Sparky,
That was always Tesla's secret. He used very high frequencies to perform his "tricks". When he lit the lights every mile for 16 miles with no wires in between, it was also with high freq.. I must have a dozen Tesla books, including a book of his notes, and while he thought 60 hz was good end user stuff, he wanted to deliver at much higher, which proved very impractical.

THAT was how he invented the radio, not that other guy who's name I forget (according to the 1943 decision of the Supreme Court anyway), by playing with this stuff.

'nuff said for Sunday morning.

Sparky66wv, MAN my head hurts from being slammed around so much. [Linked Image]
Posted By: pauluk Re: Flamed and need reassurance - 09/15/02 02:37 PM
We have a TV program in England called "Science Shack." A few weeks ago they did a show on lightning, so I made a point of watching.

At one point they took the presenter into a research lab, suited him up, and hoisted him into the air toward a high-voltage source charged at several hundred kV. He was drawing sparks from his fingertips like something out of a 1930s sci-fi picture!

The other impressive demonstration was putting him inside a Faraday Cage and hitting it with a 1 megavolt discharge. The slow-motion pics clearly show the arc tracking around the cage, leaving him perfectly unharmed inside.
Posted By: tsolanto Re: Flamed and need reassurance - 09/15/02 03:30 PM
It's simple OHM's law

I=E/R

120v/10,000 ohms (roughly your body inpedance) = 12ma

It all has to do with the electrical impulses from the heart. If 10ma is flowing = and opposite to the electrical impulse from the heart it can stop it from beating.

If you are unfortunate enough to come in contact with 18,000volts....See YA...

18,000volts/10,000ohms = 1.8amps now we are cooking flesh.

[This message has been edited by tsolanto (edited 09-15-2002).]
Posted By: sparky Re: Flamed and need reassurance - 09/15/02 11:58 PM
hey, i found the 'lightning dude' here.....

here's his site


looks like Zeus!

[This message has been edited by sparky (edited 09-15-2002).]
Posted By: motor-T Re: Flamed and need reassurance - 09/16/02 12:50 AM
Well heres my nickels worth.
Generally the human body has between 800-1000 ohms resistance as typical. Body internal resistance, contact resistance, moisture,duration of voltage, as well as the path of the current, we always tell our apprentices 'Right hand right.
According to our little handy chart: 16ma shock is painful just about to the point where you cant let go called" threshold" You may be thrown clear.
23ma shock painful severe cant let go- muscels immobilize- breathing stops
1000ma ventiricular fibrillation(usually fatal)length of time.....0.03 seconds
at 100ma 3.0 second duration.
Generally voltages of less than 40 volts to ground are considered safe. Voltages 50 volts and greater is considered lethal.
And we are required to ground for voltages higher than 50 volts according to 250.20(B)

a 9ma shock is Painful-but can still let go.

Seems to be some misinformation out there.
Mark
Posted By: Sean WB Re: Flamed and need reassurance - 09/16/02 03:24 AM
500 ohms for each appendage, i.e 500 ohms X2 legs, + 500 ohmsX2 arms, + 1000 ohms torso= 3000 ohms .This is what the medical society holds for human electrical resistance for defibrulating equipment etc etc.AJM
Posted By: sparky66wv Re: Flamed and need reassurance - 09/16/02 03:31 AM
Even contact area plays a part in the numbers here... Temperature, humidity, the phases of the moon (just kidding [Linked Image])

I guess one would have to meg themselves with 1 cm square copper plates as the electrodes, with a hygrometer, a thermometer, a barometer ? (does a vacuum make a difference?), an effective way to measure humidity of the skin, and at varying voltages to get any kind of usable data.

Heck, the iron, zinc, aluminum, magnesium, copper, and mineral content of your blood would cause nearly an infinite number of variables to contend with...

Any volunteers?

Steve, very cool pic! I'm going to go browse his site now...

[Linked Image]

[This message has been edited by sparky66wv (edited 09-16-2002).]
Posted By: pauluk Re: Flamed and need reassurance - 09/16/02 07:08 PM
I've always been led to believe that it is the outer layers of skin which provide the greatest amount of resistance. Once below that, either by contact with an open wound or by the application of a high voltage which burns and breaks down the skin's resistance, the resistance of the internal body tissues is quite low.

Contact area, wetness of skin, etc. all play a major part. At the extreme, I can lightly touch one finger of each hand to the probes of a low-voltage 0ohmmeter and get a reading of several megohms. At the other extreme are the figures posted elsewhere from judicial executions which indicate a head to ankle resistance of as little as 133 ohms in one case.
Posted By: sparky Re: Flamed and need reassurance - 09/16/02 08:28 PM
Paul,
that can probably be backed up with mortality & morbidity reports re; path(s) of least R = vasculature compromised....
( thus amputation)
[Linked Image]
Posted By: motor-T Re: Flamed and need reassurance - 09/16/02 08:47 PM
Quote
Dry Conditions: Current = Volts/Ohms = 120/100,000 = 1mA
a barely perceptible level of current

Wet conditions: Current = Volts/Ohms = 120/1,000 = 120mA
sufficient current to cause ventricular fibrillation

This is from one of Joe's suggested links.
Body resistance is going to vary according to conditions.
So we have under dry conditions 100,000 ohms down to 1000 ohms thats quite a variation.
As far as difibrillation they rule is to start out at 200 Joules and work up, a child of course they start at 50.
As I said seems to be some misinformation out there.
Mark
Posted By: sparky Re: Flamed and need reassurance - 09/18/02 10:40 AM
Quote
Body resistance is going to vary according to conditions.
thus the biphasic model defibs....i wonder if there are biphasic electric chairs too??
Posted By: motor-T Re: Flamed and need reassurance - 09/18/02 11:44 AM
According to my source, during a code, the De-fib machine is in Joules, and the first shock is started at 200, then progressively moved up to 360, if the Pt is still in fibrillation they start again only this time it is started the second time at 360.
For this procedure Body resistance is of no concern, but stopping the fibrillation is whether it be Atrium or ventricular. They grease the paddles with a conductive lubricant and one goes on the left side and to the center of the chest, it is not like a Hand to foot electricution. Didnt someone say that for Legal electrocutions the body resistance is down to about 130 ohms at 25000 volts, .......Talk about overkill huh ? That ought to do it and then some.

Mark
Posted By: pauluk Re: Flamed and need reassurance - 09/18/02 06:40 PM
Mark,

The chair is more like 2000 to 2500V rather than 25kV. The document I quoted did indeed show that in one case the prisoner's body resistance dropped as low as 133 ohms. (This was Fla. before they pulled the plug.)

On the defib issue, a medical drama show (British) the other night did actually quote 360 joules for the second and third attempts (they didn't mention the energy on the first).
Posted By: motor-T Re: Flamed and need reassurance - 09/18/02 08:44 PM
Paul of the UK,
As far as the the electric chair goes I really dont know what voltage it is, all I know is that when they were going to 'Fry' Ted Bundy, a radio station in Fla was asking everybody not to use any power, until it was over,,,.. bordering on the macabre, but it is lethal.
As far as the De-fib unit My source works in a intensive cardiac care unit and their method is as I described and their is no thought about what the body resistance is, If the patient is in shock they are cold and clamy anyway which has got to reduce the body resistance.
My whole point was the environment in which this takes place, an electric shock and the severity of the shock will be dependant on the prevailing conditions, ie if you are standing ankel deep in water a 50-70 volt jolt is probably more than enough to be lethal. And as someone pointed out Ohms law works,.. always
Since we have been talking about DIYers, I remember one telling me he never worried about 'House-hold current because it was only 110 volts', as strange as that was, the US Navy came out with a training film, many moons ago called, "110 volt, the deadly shipmate", and very graphically drives the point home, one shot i remember to this day is some Steward sticking a metal knife in a toaster... Respect is what it is all about.

Mark
Posted By: George Corron Re: Flamed and need reassurance - 09/19/02 10:37 AM
"The Chair" that I played with (I worked in a prison system in a non-death penalty state, BUT the chair was still there) was 2,500 volts. "Sparkies" last client was a cop killer in the 50's, but was actually one of the originals from about the turn of the century.

Just thought I'd pass it along.
Posted By: JBD Re: Flamed and need reassurance - 09/19/02 05:59 PM
For those interested in history, there is a book coauthored by the first US person to be executed by an electric chair. It goes into all of the design and testing to insure a humane operation.

The name is "A Peep Into The Twentieth Century". Sorry I can't remember the author.

[This message has been edited by JBD (edited 09-19-2002).]
Posted By: Joe Tedesco Re: Flamed and need reassurance - 09/19/02 06:36 PM
A Peep into the 20th Century
by Christopher Davis

Sumner Locke Elliott
"...a brutal case of man's inhumanity to man...because he is a beautiful writer he has conceived it as poetic horror story."

Book Description

A National Book Award nominee, A Peep Into The 20th Century is about the first electrical execution in 1890 and the war between Edison and Westinghouse for the soul of electricity's first deliberate victim.
http://www.wikipedia.org/wiki/Main_Page
Posted By: pauluk Re: Flamed and need reassurance - 09/19/02 08:21 PM
Mark,
All the quotes I've seen give the chair voltage as between about 1700 and 2600V, although in many cases they apparently reduce the voltage after a few seconds. A quick search came up with these:

GA: 2000V 4 sec, 1000V 7 sec, 208V 2 min.
AL: 2500V 20 sec, 250V 100 sec.
VA: 1825V 30 sec, 240V 60 sec.
??: 2400V 7 sec, 600V 17 sec.

The initial higher voltage is supposed to knock out the brain & nervous system instantly.

George,
Trying to place where that would have been from the list I have here in conjunction with your location. You said state, but would that by any chance have been the District of Columbia? Just morbid curiosity!

I seen an oft-quoted value of just 32 volts as being the lowest potential which is on record as having proved fatal.
Posted By: George Corron Re: Flamed and need reassurance - 09/19/02 11:37 PM
Roger Paul, The good ole State of Confusion [Linked Image]
Posted By: Bjarney Re: Flamed and need reassurance - 09/20/02 02:31 AM
Paul, I knew it! There had to be some use for increased-voltage starting!
Posted By: pauluk Re: Flamed and need reassurance - 09/20/02 07:45 PM
George,
Thought it might have been Washington D.C. The only other non-death-penalty state at present bordering Va. appears to be WV, and I know they were the last state to adopt the chair in 1949, so it wouldn't have been a turn-of-the-century installation.

BJ,
Hee-hee! Gives new meaning to the term "jump start." [Linked Image] But did you hear about the proposed new NEC rule? In order to provide greater safety against shock electric chairs will be required to be fed via a GFCI -- [Linked Image] [Linked Image]

P.S. Re "State of Confusion," I ran into somebody the other day who was convinced that America has 52 states. No way could I get him to believe that it's only 50.
(And I've lost count of the number of people here who don't realize that Washington D.C. and Washington State are two different places on opposite sides of the country!)


[This message has been edited by pauluk (edited 09-20-2002).]
Posted By: Bjarney Re: Flamed and need reassurance - 09/22/02 02:30 AM
Paul, in the vain of, “…electric chairs will be required to be fed via a GFCI,” I wonder in hospital surgery rooms if electronic “give me 360 joules!” defibrillators are required to be fed from ground-fault-interrupter circuits?
Posted By: sparky66wv Re: Flamed and need reassurance - 11/20/02 04:39 PM
Got this in my email today:

Quote
I was thinking some at work yesterday and i realised that the way you had me conceed was by saying "it's basic ohms law." The thing about that is, ohm's law is DC math. Most of my argument was from an AC standpoint (such as power transmission), in which you can have an extremely low voltage produce an extremely high current. Sorry to burst your bubble bud ^_^

-Argile

Comments please.

I'm growing very tired of this stubborn and ignorant fool.

[Linked Image]

I replied:

Quote
If you would be so kind as to explain your theory on how impedance or reactance could make a difference in this matter. It takes a voltage potential to push the current through. On ECN, I've had Electrical Engineers back me up. You can believe whatever you want, but please do not bother me with it. I'm on my 23rd work day in a row and I don't have the time for this. I have posted your email on the thread at ECN and I'll let my comrades handle this for me.

[This message has been edited by sparky66wv (edited 11-20-2002).]
Posted By: Scotts Re: Flamed and need reassurance - 11/20/02 05:03 PM
66,
First of all 23 days in a row. WOW. I have always said when you work for yourself you would rather be busy than not. Have argile look at this link. The document is large but it has the information you are looking for. It backs up what you say on page 14. Let him argue with the Center for Disease Control. http://www.cdc.gov/niosh/docs/2002-123/pdfs/02-123.pdf

Scott

Caution to all. This is a large file. 1.7M

[This message has been edited by Scotts (edited 11-20-2002).]
Posted By: sparky66wv Re: Flamed and need reassurance - 11/20/02 05:10 PM
Scotts, linkie no workie... [Linked Image]

What did you search under? I've found 1192 under "electrocution"... Way too many to weed through during lunch hour.

Thanks.

Just double checked, actually Oct. 26th was my last day off, so this'll be 25 days in a row.

[This message has been edited by sparky66wv (edited 11-20-2002).]
Posted By: CTwireman Re: Flamed and need reassurance - 11/20/02 05:27 PM
I'm no engineer, but I did take DC and AC Circuit Theory in school.

Virgil, you said all that you had to: Ohm's law applies to everything!

You are wise not to waste your time on this matter. Time is too valuable!
Posted By: Scotts Re: Flamed and need reassurance - 11/20/02 05:48 PM
66
I tried the link and it worked for me. I e-mailed it to you so hopefully you can get it that way. Cool website!
Scott
Posted By: sparky66wv Re: Flamed and need reassurance - 11/20/02 06:04 PM
This Argile guy's gonna end up making me take a long lunch...

It's good to be the boss! - to paraphrase Mel Brooks...

I'll check it out and see...

Hmmm, my Acrobat reader must be out of date.

I'll see if I can find it in the search on the CDC Website Homepage.

Scotts, what is the page titled?

I'll try it with my reader already open...


Ahhhh... I'm downloading it with a Right Click and Save-As... I think this'll work...

Hour and a half lunch and counting...

I'm getting 1.7 Megs of something..

This'll take a while, I'm on dial-up!

[Linked Image]

Hey, It worked!

Yup, appears that 49V would be a minimum. Wish they'd come out and say it a little better though...

Thanks Scotts, I'm gonna read the whole thing when I get back home tonight.

I gotta get back to work now.

-Virgil

[This message has been edited by sparky66wv (edited 11-20-2002).]
Posted By: pauluk Re: Flamed and need reassurance - 11/20/02 08:31 PM
Virgil,
You are correct, sir! But we all knew that anyway..... [Linked Image]

Argile,
Ohm's Law is just as applicable to AC circuits as to DC.

The current which flows in an AC circuit for any given voltage depends upon the impedance of that circuit. Impedance is a combination of resistance, capacitance, and inductance, so it is true that the situation is a little more complex than for DC. That said, however, we were talking about that shock current that would flow through a human body, which possesses neither inductance nor capacitance is sufficient magnitudes to make much difference. In any case, the impedance of the circuit is still constrained by the overall series resistance, i.e. it cannot be less.

In other words, for 10mV to give rise to even a 10mA shock current, Ohm's Law dictates that the DC resistance or the overall AC impedance would need to be 1 ohm or less. The human body just isn't that conductive.
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 09:41 PM
You are all sadly mistaken if you believe that for one ohm's law applies to AC as well as DC. Really, his main argument doesnt even take into consideration what i'm saying about a transformer...he's talking the voltage applied directly to you (though i believe he does at some point make the statement that the transformer idea is wrong...what a joke) But whether or not ohm's law applies isnt really the key issue. The guy is stating that a low voltage cannot kill you (which was his backup statement for "amperage isnt what hurts you"), while i'm stating that if coupled with the proper transformer, any amount of voltage can kill you! Even when applied to DC (though it would take a much higher amperage, due to the fact that DC when applied to a transformer only creates a small pulse of energy and the the field collapses). Like my entire argument on the post stated (until i started to get tired and a little confused :), this is exactly what they do with power transmission. They basically step up the voltage with the transformer, so as to step down the current. The reason for this is they want to be able to use a wire that's rated for a lower amperage. Why? Well if any of you are as good as you claim to be (which i'm doubting at this point, considering it appears that none of you have a grasp on the use of transformers and/or power transmission), then you would know that a larger amperage requires a larger wire (duh!). Therefore, a smaller amperage requires a smaller wire (which means less poles and whatnot that they have to put up to support the weight of the wire...if any of you have seen these things up close, they can get pretty big..).
Posted By: CTwireman Re: Flamed and need reassurance - 11/20/02 09:49 PM
Quote
You are all sadly mistaken if you believe that for one ohm's law applies to AC as well as DC.

Huh? How does Ohm's law not apply to AC circuits? Care to explain this one?

I guess all my teachers and textbooks are wrong. [Linked Image]
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 10:02 PM
guess my teacher was wrong then...
however, the question of whose teacher is wrong is not the issue...
Posted By: txsparky Re: Flamed and need reassurance - 11/20/02 10:11 PM
What a D5%$head !!!
Argile.... ,Did you listen to your instructor?Is he really as naive as you?
Give us something to support your theory/.
Posted By: RR Re: Flamed and need reassurance - 11/20/02 10:12 PM
Please enlighten us Argile, as to how you define Ohm's law in AC terms and exactly who taught you this.

This board, Mr. Ohm, Mr. Volta and Mr. Ampere all disagree with you.
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 10:18 PM
Gee, talk about maintaining a professional conversation...i'm sure if anyone came to this board who was unfamiliar with electricity, they would say that i was the correct one, because you all sound like a bunch of 9 year olds. Grow up.
Secondly, as i stated in my response to the guy who first responded to me, IT'S NOT ABOUT WHOSE TEACHER IS RIGHT OR WRONG...that wasnt even my point! Really, it wasnt even a supporting point! Respond to my points if you're going to respond at all, because you're dodging my main point (the part that i KNOW is correct).
Posted By: electech Re: Flamed and need reassurance - 11/20/02 10:39 PM
Ohms law applies whether your units are DC, ACpeak, or ACrms.

A transformer with a secondary rated at (for example) 10 VAC 1 amp has a nominal output of 10 volts RMS and is rated for 1 amp of continuous output. That doesn't mean it will magically drive one amp into any and every load, but rather it is rated to not catch on fire or sustain insulation damage while delivering up to 1 amp of continuous current, and its output voltage should be reasonably close to 10 VAC while delivering up to 1 amp to the load. That's all. Similarly your car battery won't drive 500 "cold cranking amps" through you if you touch its terminals. If you touch the output of a 10v transformer (or battery) and measure the current through your body, you would likely measure far less than 5mA and not feel a thing. If you think a transformer will always run it's rated current through your body, then wouldn't it follow that you absolutely cannot be killed by any transformer rated at under 5 mA? That is plainly false.

Ok, I just did a little experiment...I put myself in series with a current meter connected to a "12 VAC 1.3A" power supply. The output of the 12VAC supply measures 14.7 VAC(rms), and I know this particular supply will deliver over 8 amps for several seconds when shorted. Holding one lead of the DMM between the thumb and index finger of one hand while holding the power source output with the other hand gives a current reading of .28 mA (0.00028 amps), for a calculated body resistance (at this voltage) of 52500 ohms.

Experiment #2. 98 VDC, measuring current through me hand-to-hand as before --- 0.47mA for a calculated body resistance of about 21000 ohms. This is a span powered T1 line I'm touching in this test. I wouldn't recomend doing this, but when you work in the telecom field you touch these by accident all the time (because you know its no biggie, else one would be more careful) and get used to it. I can't even feel it with my fingertips (should try the tongue method!).

Experiment #3 -a 200VDC communications circuit. No way, it bites!

I'm ready to jump into that bath with the laptop now...
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 10:47 PM
I didnt say a transformer of that sort. Clearly that sort is not suited to power transmission. Though, your voltage isnt enough to do any human damage with any transformer...but if you had 10kv and stepped it down to 10mv, the resulting amperage would be very very high (the opposite of power transmission)
Posted By: sparky Re: Flamed and need reassurance - 11/20/02 10:48 PM
Such impedance there, electech.....
[Linked Image]

Argile, perhaps you should
check out this link ....
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 10:57 PM
Nice Graph: Check
Response to my point about power transmission or amperage being what kills you: _____
It doesnt even have anything about the little sub-argument which i'm trying to avoid about DC math being used in AC systems
Posted By: resqcapt19 Re: Flamed and need reassurance - 11/20/02 11:05 PM
Argile,
How can 0.001 volts cause any real amount of amperage to flow through a human? The current is limited by the impedance of the path. High impedance equals low current. Ohms law does apply to AC and is used every day. The only real difference is that you use impedance in place of resistance.
Don

[This message has been edited by resqcapt19 (edited 11-20-2002).]
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 11:08 PM
If that is true, then how does power transmission work? How do transformers that step-up current and step down current work? (well ig uess that last one isnt really a rhetorical question, but you get the idea). Both of these are used every day also.
Posted By: resqcapt19 Re: Flamed and need reassurance - 11/20/02 11:14 PM
Argile,
What are you asking about in your last post????????????
Don
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 11:16 PM
See, you cant even respond to my points because you dont even know what power tranmission is about or who it works...like i said before, it's gotta be the same way throughout the entire board (and now i see you, along with sparky, dont understand it)
Posted By: Scotts Re: Flamed and need reassurance - 11/20/02 11:22 PM
Argile,
Quote from you.

You are all sadly mistaken if you believe that for one ohm's law applies to AC as well as DC.

Please check out the following link. I will admit that I have not checked out the entire site, but it does appear as if it is from NASA. If you think you are smarter than NASA then I think you should start desiging rockets.
http://www.grc.nasa.gov/WWW/K-12/Sample_Projects/Ohms_Law/ohmslaw.html

As for the rest of your comments you appear to be all over the place. Yes it is the current that kills you, not the voltage. Current is kinetic energy and voltage is potential energy.

Now please stop pissing off the people on this fine board. I enjoy it too much for someone to come in and start spouting off irrational stuff.
Scott
Posted By: RR Re: Flamed and need reassurance - 11/20/02 11:24 PM
I think our chain is being pulled here folks. We're being hoodwinked, scammed and teased.

Some people just crave attention...even if they're wrong.
Posted By: Scotts Re: Flamed and need reassurance - 11/20/02 11:26 PM
RR
That is true, maybe if we ingore him he will go away.
Scott
Posted By: sparky66wv Re: Flamed and need reassurance - 11/20/02 11:26 PM
Wow! [Linked Image]

I think we should lock this one up.

Obviously we're all idiots here!

[Linked Image]

Something about arguing on the internet and wrestling with pigs...

Lock it up Webmaster, before this gets out of hand! (Please!)
Posted By: resqcapt19 Re: Flamed and need reassurance - 11/20/02 11:27 PM
Argile,
Your question doesn't make a point that can be responded to. The current through a circuit supplied by a transformer works like all other circuits. The amount of current is determined by the application of Ohms law based on the voltage and impedance of the circuit.
Don
Posted By: Scotts Re: Flamed and need reassurance - 11/20/02 11:28 PM
Sparky66,
Once agian you are the voice of reason.

Never try to teach a pig to sing. You only waste your time and annoy the pig.
Scott
Posted By: sparky Re: Flamed and need reassurance - 11/20/02 11:42 PM
i had a pig that drank Coors, but he's in the frezzer now....
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 11:44 PM
resqcapt19: Not true...please find some info on power transmission
Scotts: where does that site say ANYTHING about AC!? I already stated that my main argument was about how low voltages can kill you. Furthermore, my comments are not all over the place: they're clearly focused on power transmission proving the fact that low voltages can kill.
Sparky: that is clearly a well thought out point to add to this argument! By the way...you'll want to note what my original point from all the way back on that fark post was just proven TRUE by one of the comerades who you said would back you up "Yes it is the current that kills you, not the voltage."
Posted By: CTwireman Re: Flamed and need reassurance - 11/20/02 11:51 PM
Moderator, please delete this thread.
Posted By: Argile Re: Flamed and need reassurance - 11/20/02 11:54 PM
Avoidance...sign of defeat. I think i've proved my point well enough. Sparky: do some research on power transmission then get back to me.
Posted By: Bill Addiss Re: Flamed and need reassurance - 11/21/02 12:09 AM
Argile,

Please do not insult our intelligence. If you have a statement to make please make it.

Using your own example where voltage is stepped down to 10mV please explain how that will harm someone. And leave out the attempts at insult to people here.

10mV applied to a person is your example.
What current will flow through them?

Bill
Posted By: sparky66wv Re: Flamed and need reassurance - 11/21/02 12:15 AM
Yes, the current kills, but it must have some voltage present to do so. There are plenty of circumstaces that involve current but no voltage to ground> the neutral conductor for instance.

Current must also be available, for instance, electric fences do not supply enough current to kill, but plenty of voltage. Once again, you are correct in saying that it's the current that kills, but current alone, without voltage to ground, will not do anything.

The trasmission lines and transformers here would never qualify for "low voltage", I don't know what type of transmission you are referring to...

I'm not a professional debator, so forgive my lack of arguing skills.

Some questions for all to ponder:

What happens when one becomes parallel with a grounded conductor? What about in series (with a load)? How does this relate to Argile's point of view? Must there be, say, 50V present from one side to the other when the plumber removes the water meter and gets hit by the ground system?

Please, I am trying to see your point of view.



[This message has been edited by sparky66wv (edited 11-20-2002).]
Posted By: sparky Re: Flamed and need reassurance - 11/21/02 01:59 AM
[This message has been edited by sparky (edited 11-20-2002).]

[This message has been edited by sparky (edited 11-20-2002).]
Posted By: electure Re: Flamed and need reassurance - 11/21/02 02:27 AM
The return of DSp...?
You guys remember who.
There's no room for non-helpful, self-serving...etc. junk here.
We're here to help each other.

[This message has been edited by electure (edited 11-20-2002).]
Posted By: txsparky Re: Flamed and need reassurance - 11/21/02 02:32 AM
Looks like Steve is biting his tongue. [Linked Image]
Posted By: sparky66wv Re: Flamed and need reassurance - 11/21/02 02:57 AM
Scott W., Dsp in spirit but not him. I won't reveal Argile's real name. I think he's from the UK, so Pauluk would be the best for convincing him.

Unfortunately, I believe Argile is firmly convinced that he understands things on an entirely different level than we do, only to be misled on some basic electrical theory.

Perhaps he understands the Tesla "free power" concept and we're just mere mortals!

Even with wet hands (1000 Ohms) it'd take 10 Volts to push 10mA through.

The CDC website Scotts mentioned says "...as low as 49 Volts." (But they say some other things I don't wholy agree with... i.e. equipment grounding attached to ground rod being the safety method, rather than the bond to the grounded conductor doing the real work to open an OCPD...)

Someone mentioned a 12V car battery causing electrocution, but that'd be some low resistance!

I would assume that even in the open grounding electrode, that some measurable voltage between the open and ground would be evident.

[This message has been edited by sparky66wv (edited 11-20-2002).]
Posted By: go-go Re: Flamed and need reassurance - 11/21/02 03:42 AM
[Linked Image from thisfunsforyou.com]


WOW!!!
Posted By: ElectricAL Re: Flamed and need reassurance - 11/21/02 06:46 AM
Hey Argile,

Please allow me to make a three points.

I. When I was in sixth grade, I put together a project with an Erector Set that made use of the small 1/24 HP 120 V electric motor in the Set. Out of the Erector parts I fashioned a battery holder for 3 "D" cell 1.5 V batteries, and two hand grips. The battery holder had one extra feature. There was a hand crank that turned a gear. A sprung contact racheted against the teeth of the gear. As the gear was turned by the crank, the contact would drop from gear tooth to gear tooth, momentarily breaking the connection of the positive battery terminal. Here's the way this was set up:

First hand grip is connected with a wire to the negative battery terminal.

Positive battery terminal is connected to the contact on the gear teeth.

Gear shaft is connected with a wire to one of the 1/24 HP motor power cord plug blades, AND with a wire to the Second hand grip.

The other 1/24 HP motor power cord plug blade is connected back to the negative battery terminal.

What I'm describing is the basic "collapsing magnetic field pulse generator". It was quite effective. And, one day at recess, out on the playground, I got about 12 kids to join hands in a circle with the first and last kids holding the hand grips. I turned the crank and everyone jumped back. I got my first rush of "electrical power", even though I wasn't in the circuit.

Two things made this work with a 4.5 V DC source. One. The motor had a large magnetic core and a lot of windings that resulted in a dense magnetic field being created while the contact was resting against the gear and a small DC current flowed. Two. When the contact dropped to the next gear tooth, the current sustaining the magnetic field shut off very fast, causing the magnetic field to collapse very fast. The the magnetic field, collapsing, moves down into the wires that carried the current that sustained the field. And in moving, the collapsing magnetic field generates a voltage. The faster the collapse, the higher the voltage, BUT, the quicker the magnetic field ends, thus ending the generator effect. Right Hand Rule -- Physics 101.

The voltage created by the collapsing magnetic field is in the same polarity as the batteries. This high voltage pulse pushes current in the same direction that the DC battery current is already flowing in, except the contact, no longer touching a gear tooth, is in mid air between gear teeth, and the only path left in the circuit is through the circle of my 12 now ex-friends. Once the contact drops down to the next gear tooth, the battery circuit is re-established and the magnetic field is re-created, AND simultaneously shorts out the high voltage experience in the high resistance path through my ex-friends. Parallel circuit -- Circuit Theory 101

The energy, the Watts, delivered in the high voltage DC pulse is the "area under the curve" described by the voltage. This is a very small energy, inspite of the high voltage, and it is what saved my ex-friends from any harm. The equivalent of a static spark. While the voltage got to transmission line voltage level, no harm was done. Had these 12 kids been connected to an actual transmission line, with its huge power level, they would have been my dead ex-friends. Power = Volts x Amps -- Physics 101

II. Ohm's Law applies to all AC and DC circuits.

After learning about DC circuits, a little more math is learned. First one studies AC in purely resistive circuits, then one studies how capacitors and coils (inductors) shift current and voltage apart in time. The math allows one to reduce the complex time varying phenomena into vector calculus, and the LaPlace Transform simplifies the vector calculus to algebra. The language of math, correctly applied, allows Ohm's Law to be calculated simply as if the AC circuit were a DC circuit, all the time maintaining the vector direction information that is the complex phase relationship of any AC circuit. -- Circuit Theory 201

III. Taking a power transmission transformer, and "turning it around", that is, putting 120 V AC on its primary in order to get a AC milliVolt output of enormous Amperage, will result in the enormous amperage flowing ONLY IF THE OUTPUT IS SHORTED by a conductor of extremely low resistance. The human body is not that conductor, as its resistance is five or six orders of magnitude greater than what you envision. -- Physiology 101

Respectfully,

Al
Posted By: Admin Re: Flamed and need reassurance - 11/21/02 07:11 AM
If anyone would like to pursue this further, please start a new thread.
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