keithd@cadovax.UUCP (Keith Doyle) (02/05/85)
[......]
Anyone out there in net-land interested in discussions about Nikola Tesla
or Tesla coils?
One of my Tesla books indicates that the effects of high-voltage discharges
change characteristics considerably depending on the frequency of the
coil. I've always wanted to build a coil where I could observe these
different effects. Right now I have a simple Tesla coil made with a
neon-transformer driving a 2 1/2 foot coil and surplus oil-filled
H.V. capacitor. Unfortunately, Tesla's experiments were performed
with large multi-pole generators (400+ poles!) that he constructed
himself. I wonder what the simplest method of getting high current
at frequencies in the range of 50khz to 500khz? Recently at a
surplus store I ran into an old rack-mount R.F. amplifier. Could
something like this be used to drive a coil at varying frequencies?
How could I keep from smoking the amplifier? Or, as an alternative
what transistor circuits could be used as amplifiers? I'd like
to be able to take a simple variable oscillator circuit and give
it enough current driving capability to power a coil who's primary
is probably only a couple of ohms.
In addition, what kind of successes, horror stories, etc. have any of
you out in net-land with home-made Tesla coils?
Keith Doyle
{ucbvax,ihnp4,decvax}!trwrb!cadovax!keithdksbszabo@wateng.UUCP (Kevin Szabo) (02/10/85)
I for one would love to hear more about Tesla, the great unsung hero of electrical history. I believe that he and Edison were great adversaries, to the extent that Tesla used to send amazing machines to Edison's technicians. The technicians were baffled and couldn't figure out what made the stuff tick. I also believe that Westinghouse owes a lot of their profits to the brilliance of Tesla. Kevin -- Kevin Szabo watmath!wateng!ksbszabo (U of Waterloo VLSI Group, Waterloo Ont.)
keithd@cadovax.UUCP (Keith Doyle) (02/23/85)
[........] >I for one would love to hear more about Tesla, the great unsung hero >of electrical history. I believe that he and Edison were great adversaries, >to the extent that Tesla used to send amazing machines to Edison's >technicians. The technicians were baffled and couldn't figure out what >made the stuff tick. >I also believe that Westinghouse owes a lot of their profits to the brilliance >of Tesla. > Kevin Yes, apparently Westinghouse was in financial trouble one time and Tesla gave up all his patent royalties in order to help out. Tesla's motivation stemmed from the fact that Westinghouse believed in him when no one else did. Giving up his royalties however, represented a significant amount of money. I hadn't heard the story about sending machines to Edison's techs. Do you know where the story came from? I still fume every time I hear someone bestowing credits on Edison. Has anyone (besides me) seen the old film footage of the elephant being electrocuted by Edison trying to prove that A.C. current was dangerous? Apparently about the same time, Tesla was giving demonstrations in Madison Square Garden illustrating how safe it was by passing megavolts through his body to illuminate bulbs. Keith Doyle {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd
stekas@hou2g.UUCP (J.STEKAS) (02/28/85)
In 1888, Tesla sold Westinghouse the rights to his AC patents for a few hundred thousand dollars up front and royalties of $2.50 per horsepower sold. By 1897, Westinghouse was in financial trouble and about $12,000,000 in debt to Tesla. In apreciation of Westinghouse's support Tesla sold the patents outright for $216,000! Don't forget, those were the days when you were doing well to make $500 a year. Tesla's association with Edison's laboratory wasn't only as an outsider. In fact, Tesla was an employee of Edison's and worked in his lab. Tesla told Edison he could improve the efficiency of his dynamos and Edison offered him $50,000 if he could do it. A year later, Tesla had completed the job and asked to be paid. Edison dismissed the agreement as a joke and offered Tesla a raise to $18/week. Tesla walked out. The Tesla(AC)-Edison(DC) feud was long and bitter. Edison had more than his pride riding on DC, he had bet his fortune as well. No dirty trick was too low for Edison to employ on his own behalf. He used his Wall Street connections to financially strangle Westinghouse and promolgated the idea that AC was dangerous. He and his cohorts even had the electric chair at Sing-Sing prison wired with AC to emphasize its "lethal" nature! These facts come from the book "Tesla: Man Out of Time" by Margaret Cheney. Jim
dgary@ecsvax.UUCP (D Gary Grady) (03/01/85)
<> > The Tesla(AC)-Edison(DC) feud was long and bitter. > ... > [Edison] and his cohorts even had the electric > chair at Sing-Sing prison wired with AC to emphasize its "lethal" nature! Actually, I have heard that AC really is somewhat more dangerous than DC of a comparable voltage because AC has a greater likelihood of inducing heart fibrillation. Anyway, I read somewhere that Edison or one of his pals proposed at one time that execution by electricity (what we now call "electrocution") be called, in keeping with the Guillotine tradition, "Westinghousing" !!! (And you wonder why companies guard their trademarks so jealously... I actually feel some sympathy for the producers of the "Ayds reducing plan".) -- D Gary Grady Duke U Comp Center, Durham, NC 27706 (919) 684-3695 USENET: {seismo,decvax,ihnp4,akgua,etc.}!mcnc!ecsvax!dgary
jans@mako.UUCP (Jan Steinman) (03/02/85)
In article <406@hou2g.UUCP> stekas@hou2g.UUCP (J.STEKAS) writes: >The Tesla(AC)-Edison(DC) feud was long and bitter... No dirty trick was too >low for Edison to employ on his own behalf. He... promolgated the idea that >AC was dangerous. He and his cohorts even had the electric chair at >Sing-Sing prison wired with AC to emphasize its "lethal" nature! > The story I heard was that the first person to sit in that particular chair lived through several attempts, and it was this ghastly experience (to Edison's chagrin) that finally won the war in favor of AC for power and DC for electric chairs! (I think I read all this in a Popular Electronics article -- can anyone verify?) -- :::::: Jan Steinman Box 1000, MS 61-161 (w)503/685-2843 :::::: :::::: tektronix!tekecs!jans Wilsonville, OR 97070 (h)503/657-7703 ::::::
keithd@cadovax.UUCP (Keith Doyle) (03/05/85)
[.........] >Actually, I have heard that AC really is somewhat more dangerous than DC >of a comparable voltage because AC has a greater likelihood of inducing >heart fibrillation. I believe there's more to it than AC vs DC when you're talking about danger. Heart fibrillation has to do with the frequency of the A.C., Tesla's 'safe' demonstrations used high frequency high voltage low current A.C.. Edisons 'unsafe' demonstrations proportedly used a 'chopped' D.C. which is apparently worse than sine-wave A.C. (Edison didn't have any A.C. generators lying around, he adapted his D.C. stuff ) >(And you wonder why companies guard their trademarks so jealously... I >actually feel some sympathy for the producers of the "Ayds reducing >plan".) Just think! if they discover a new horrible disease and inadvertently name it UNIX we'll all be out of a job! Keith Doyle {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd
guy@enmasse.UUCP (Guy K. Hillyer) (03/12/85)
>>(And you wonder why companies guard their trademarks so jealously... I >>actually feel some sympathy for the producers of the "Ayds reducing >>plan".) > >Just think! if they discover a new horrible disease and inadvertently >name it UNIX we'll all be out of a job! I feel compelled to point out that "UNIX" already has a homonym that is pretty unpleasant... And you may ask yourself, "What does this have to do with electronics?" Sorry, I won't do it again. I promise! -- -- guy k hillyer {decvax,linus,allegra}!genrad!enmasse!guy enmasse!guy@harvard.arpa "Don't drink soap! Keep out of eye! Dilute! Dilute! OK!" -- Dr. Bronner