[Prev][Next][Index][Thread]

High volt. vs. low, also 60 bps re-visited



 Dave, Barry, Malcolm, Finn, Reinhard, Richie, all,
 
 I did a couple of new tests:
 
 Test 1.  I compared high voltage, small cap operation with lower 
             voltage, larger cap operation (120 bps)  Predicted lengths
             are based upon the square law:
 
 Watts   C(uF)    scope div.     toroid       actual length  
 750      0.0147       5.3           6x26"              47"             
 750      0.031         4.9           6x26"              47"             
   (the voltage on the cap in the second test was adjusted to keep
     the input power constant. It's clear from the results that if there's
     any advantage to be gained from a higher voltage, it's very slight,
     i.e. too small for me to measure.  Reinhard will be pleased !!  
     My original tests which showed an advantage at higher voltages
     was flawed due to the use of two different NST's.  I'm measuring
     things in a more precise way these days.)  The % difference in
     voltages used, is equivalent to an increase from 15kV to about
     20kV.
 
 Of course in the recent past, I compared the TC operation while
 producing 42" sparks using the .0077uF cap at about 600 watts,
 and the .0147uF cap at the same wattage but lower voltage to
 give the same bang size.  Again, the higher voltage did not seem
 to help.  Any theoretical advantage must be too slight for me to
 measure.  
 
 Test 2.  I removed some spinning electrodes from the sync gap to
 give 60 bps, and doubled the cap size from .0147uF to .031uF to
 keep the power input ~the same.  The results were very poor.  I had
 problems with resonant buzzing and flashovers at the gap, and the
 sparks were weak and thin.  This was with the 6x26" toroid, I didn't
 try any others.  I tried firing on the negative, then the positive ac
 peaks of the input ac, but this didn't make any difference, and I 
 didn't expect any difference.  In the past (1 year ago?), I tried 60bps,
 with the .0147uF cap, and a smaller toroid, and the results were
 excellent.  Nevertheless, I'll probably abandon these 60 bps tests
 for now.  These results seem to hint that high break rates may work
 better at higher powers,  hmmmm.
 
 John Freau