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Re: TCBOR Magnifier 11-E Specs


Sorry, didn't catch the name,

The spark gaps you speak of are all valuless for Tesla coil work, period! 
 Yes some can switch in fractions of a micro second (EG&G KD21 "krytron") 
but handle only a few amps.  Some can switch tens of thousands of amps 
(Hughes 10,000 buck gap) but it takes only one pulse per minute.   Some can 
take repetitive pulses (100-1000)/second, but they are, again, limited to 
two or three amps.   I have heard rumors of a newer Hughes gap switch which 
can pop 4,000 amps, 500 times per second (government stuff)  for a mere 
megabuck or two.

Regarding ignitrons.  I cut my young teeth on these babies back in college 
in the early 1960s.  SCRs of any power were a remote dream then and nothing 
switched real power the way water cooled ignitrons did!  I had a final exam 
in a lab where we had to change out a 1000 amp ignitron group in a 100 HP DC 
motor speed regulator.  This included the water jacket plumbing too! 
 (Engineers used to have to acquire a lot of skills.)    They are sloppy as 
hell regarding turn off times and the ionized blast of mercury at 1000 amps 
may calm down 2-8 milliseconds after a current reversal .   120 hz rates are 
pushing these babies.  They can carry the juice but switch times are 
attrocious and they are limited to a few thousand volts max.  Modern 
hydrogen thyratrons switch fast, but are limited in current and voltage.

My statement remains that there exists no switch on the planet (which any of 
us have the remotest possiblity of ever obtaining) which will switch tens of 
thousands of amps at tens of thousands of volts, in micro seconds, beyond 
the old air gap rotary systems of the early 1900s!  Semiconductors are flat 
out for the forseeable future except in small tesla systems.  Some FETs may 
soon play the larger game, but will be ultra expensive.  They curently top 
out at 1500 volts.....about 6,000 volts short of the mark where real Tesla 
coil activity begins.

Single gaps for single pops have been available for years, but would 
vaporize in even small table top systems around 1kw.  I have always tried to 
limit my statements about gaps in this forum to the needs of the Tesla coil 
gap systems anyway.

Richard Hull, TCBOR

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From: tesla
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Subject: Re: TCBOR Magnifier 11-E Specs
Date: Thursday, April 11, 1996 9:38AM