Home |
Search |
Today's Posts |
#191
![]() |
|||
|
|||
![]()
Had big time Electric Shocks -- never fatal obviously
Had big time shocks that should (could) have been fatal -- ART- 13 Dynamotor Navy. 440 AC - steel mill, etc. But tis the current that does you in, not the voltage. Coupla hundred milliAmperes will do it --- URL: http://hypertextbook.com/facts/2000/JackHsu.shtml Guess my Irish hide has lots of ohms! Steel Mill Stories from the 40's (Maybe Urban Legend) 1. A lunch eater sat down and rested his head on a huge copper bus bar (voltage unknown), someone turned on the switch, he was reduced to a frazzled lump with a half a sandwich! 2. A careless electrician up high on an overhead crane, got across a high voltage line and fell into one of those giant ladles that pour out the molten steel. Not found. Maybe the old steel mill hands -- told this to the new guys to scare the hell out of em, Worked for me! Lock the distribution box, take off all jewelry, keep one mitt behind you, keep away from the chassis, -- all good advice, mostly learned the hard way. Then there was a color TV High Voltage supply ---- oocchhh !!! A teeth rattling experience. |
#192
![]() |
|||
|
|||
![]()
On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote: On 10 Aug 2003 03:22:06 GMT, (Avery Fineman) wrote: I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. As a general safety rule I'm sure you're right. However it does overlook the fact that different individuals have different tolerance levels, hence the fatality at 12V (the only recorded one, I believe) and that Polish electrician who checks for the presence of 230VAC by It also matters what the surface resistance of your skin is, and how good a "connection" to the nervous system and heart. For example, You could put dry fingers on a 9V battery and not feel a thing, but if you lick your fingers first, get a real tingle. Same voltage, but the moisture allows current to flow. In medicine, the defibrillator paddles are covered with a conductive gel, and use a precise pulse of voltage and current. In open heart procedures, lower voltage and current is used, with paddles applied directly to the heart. Of course, disrupting the heart rhythm may happen with lower voltage, especially AC or RF. Why is being careful such a problem for some? Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
#193
![]() |
|||
|
|||
![]()
On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote: On 10 Aug 2003 03:22:06 GMT, (Avery Fineman) wrote: I really don't know the medical-biological low threashold for direct cardiac stimulation through an opening in the chest cavity. I don't care to know. I care to know NOT to futz around with my or anyone else's body with anything above the "30-30" limits. As a general safety rule I'm sure you're right. However it does overlook the fact that different individuals have different tolerance levels, hence the fatality at 12V (the only recorded one, I believe) and that Polish electrician who checks for the presence of 230VAC by It also matters what the surface resistance of your skin is, and how good a "connection" to the nervous system and heart. For example, You could put dry fingers on a 9V battery and not feel a thing, but if you lick your fingers first, get a real tingle. Same voltage, but the moisture allows current to flow. In medicine, the defibrillator paddles are covered with a conductive gel, and use a precise pulse of voltage and current. In open heart procedures, lower voltage and current is used, with paddles applied directly to the heart. Of course, disrupting the heart rhythm may happen with lower voltage, especially AC or RF. Why is being careful such a problem for some? Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
#194
![]() |
|||
|
|||
![]()
On Sun, 10 Aug 2003 09:28:41 -0400, tk wrote:
Years ago (50's) I was sitting on a 240 volt 600 amp circuit breaker inside the Power Distribution Frame of an IBM 704 installed at the Air Force Computing Center in the Pentagon. A civil service operator came in early and hit the power on button...... I survived and so did the operator.... murder is murder.... whatever the reason. The full version of OSHA-approved (the US Occupation Safety and Health Administration of the Department of Labor) safety lock-out/tag-out procedure includes safety procedures such as locking out the electrical power to a piece of equipment while it is being worked on. There is one device applied to the breaker box that locks it off, and then each worker places their own personal padlock to keep that device locked, as well as a supervisor and possibly a safety engineer. The equipment cannot be turned on until every single person is finished and has cleared the area. Seems obsessive, but it doesn't produce stories like on this thread. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
#195
![]() |
|||
|
|||
![]()
On Sun, 10 Aug 2003 09:28:41 -0400, tk wrote:
Years ago (50's) I was sitting on a 240 volt 600 amp circuit breaker inside the Power Distribution Frame of an IBM 704 installed at the Air Force Computing Center in the Pentagon. A civil service operator came in early and hit the power on button...... I survived and so did the operator.... murder is murder.... whatever the reason. The full version of OSHA-approved (the US Occupation Safety and Health Administration of the Department of Labor) safety lock-out/tag-out procedure includes safety procedures such as locking out the electrical power to a piece of equipment while it is being worked on. There is one device applied to the breaker box that locks it off, and then each worker places their own personal padlock to keep that device locked, as well as a supervisor and possibly a safety engineer. The equipment cannot be turned on until every single person is finished and has cleared the area. Seems obsessive, but it doesn't produce stories like on this thread. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
#197
![]() |
|||
|
|||
![]()
(Avery Fineman) wrote in message ...
In article , (Bill Bowden) writes: Watson A.Name - 'Watt Sun' wrote in message ... In article , richard.p.henry@saic mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! Sure, but the pulse width is only a microsecond, so the average power is only 5 watts at one pulse per second. I forget the rep rate of the one I woked on but at 6uS per mile and 400 miles round trip, the rep rate would be about 400 Hz. So it's 400 times 5, or 2KW. -Bill A very rough estimate of "radar range" (time out to return of echo) is 500 feet per microsecond. For a 200 mile search radar the time out to echo return is 2+ milliseconds, depending on whether it is calibrated for statute or nautical miles. Typical PRF for those 200 mile search radars was 400 Hz (PRT of about 2.5 mSec). Average power output is Peak x ((pulse width)/(repetition time)) or 5 MW divided by 2500 = 2 KW. 2 KW concentrated in a 2 to 5 degree cone can have a devastating heating effect on human tissue. One may or may not be "in" the cone of the beam right up close to the feedhorn but, with the construction of most search radars (maritime or ground) there isn't much walk-around space to get away from the feedhorn or the very close in-person effects of microwave radiation. When working on HIGH POWER RF at any frequency, believe in the inverse square law and put as much distance from the antenna as possible...or have a trusted person down on the power controls who keeps the thing OFF while up there doing whatever. I think it would be an interesting subject to compare peak power RF effects versus average power RF effects. I can't seem to find much on that in hundreds of pages of medical-biological reports on the effects of RF radiation on human tissue. Unfortunately, that has been pretty well shunted aside so that someone can get their pet "alternate universe" speculations going on in here. :-) All this gee-whizzy speculation stuff leaves me shocked. But not fatally so... Len Anderson retired (from regular hours) electronic engineer person There are a few refs and calculations in http://arXiv.org/pdf/physics/0102007 Lu, et al (referenced) found that peak power was responsible for spark-gap transmitter injury in rats. Microwave hearing (referenced somewhat; see a review Supplement to Radio Science in 1977) also seems to be because of peak, not average, power. John John Michael Williams |
#198
![]() |
|||
|
|||
![]() Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... That's how we tested batteries when I was a kid. 'Course there was the dufus that tried it with a 90v B battery! |
#199
![]() |
|||
|
|||
![]() Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... That's how we tested batteries when I was a kid. 'Course there was the dufus that tried it with a 90v B battery! |
#200
![]() |
|||
|
|||
![]()
"K Wind" wrote in message
.. . Would 1,500VDC with 6mA capability flowing through one arm and out the other be considered lethal? At one time, I knew how much current was considered lethal, but have forgotten. No. It is actually quite hard to kill yourself with electrical shocks. There are tons easier and more likely things to die from in everyday life. 60Hz AC is most dangerous in the range of 100 to 300 mA. Current in that range sometimes causes ventricular fibrillation, whereas currents above that usually cause the heart to temporarily contract and protect itself. Very high currents, however, can dissipate lots of power in your organs and cook them, leading to a painful death if nothing stops the electrocution for several minutes. High frequency AC (like many kilohertz and beyond) should be less dangerous since it will be bound by "skin effect" and not penetrate as far into your chest cavity. DC is considerably safer than 60Hz AC, and I've read some estimates saying you need 4 times as much current to die from DC shocks. I don't know if I believe that though; I suspect there are too few cases to draw significant statistical conclusions. As I understand it (and I may be wrong here), DC is safer than AC because it doesn't cause ventricular fibrillation, so death by these shocks occur from organ damage and falling off ladders and things. Howard Henry Schlunder -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Do you recognize yourself ? | Antenna | |||
WTB: Brass "Signal Electric" key | Boatanchors | |||
WTB: Brass "Signal Electric" key | Boatanchors | |||
102-E Western Electric Tube info needed | Boatanchors | |||
FA: Pair Western Electric 106F Speakers! 6-Hrs..Left! | Boatanchors |