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DC H-Bridge Measurements
Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>
I fired up my reworked DPDT 16 rotating electrode RSG today in an H-Bridge
configuration and took some quick measurements that I am posting here.
Measurements are at the onset of a 48 inch streamer between breakout points on
a twin TC. This is quite subjective as the transition from heavy corona to an
actual streamer is not very pronounced at the lower break rates. The streamer
at 700 BPS is awesome - almost like a heat arc!
The H-bridge alternately reverses HVDC (from a low esr 6 mF pulse cap) to the
primary tank circuit, which theoretically doubles the effective voltage to the
cap (27 nF). *** is the calculated power in the primary = .5*C*(V*2)^2*BPS.
I will switch to fixed font:
BPS DCKV DCMa DC Watts ***
200 8.6 98 843 769
300 8.0 118 944 1036
400 7.2 132 950 1148
500 6.9 148 1021 1286
600 6.6 160 1056 1411
700 6.4 170 1086 1548
As BPS goes up, the streamer gets brighter and and thicker, and makes a more
pleasing musical sound than the usual AC powered TC. The lower BPS is more
efficient (as John Freau has said many times), but high BPS is more
The *** column is interesting for the 300 BPS and up cases. Obviously, the
effective voltage across the tank cap is not doubled. At 700 BPS, ***
calculates to 1086 watts with 2V = 10.7 KV. This is about 2 KV less than the
12.8 KV for true voltage doubling. That is 500 volts across each of the four
active RSG gaps.
I am more and more convinced that nothing takes the place of starting with a
relatively high DC voltage in the first place. H-Bridges, resonant charging
schemes, Marx-gap schemes and the like to effectively increase the tank cap
voltage all have their drawbacks in lower efficiency and complexity. My
H-Bridge RSG has eight stationary electrodes, for example! Back to the drawing
board . . .