My DRSSTC experience

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Original poster: Finn Hammer <f-h@xxxx>

I built my first DRSSTC and here are some results.

Topload is spun 6" by 24"
secondary is 3000 turns on a 8" by 35 former
Fres(sec) is 54kHz loaded.

K=0.2

Primary is 10pcs CD942 0.15µF/2000V 5 strings of 2 for 0.375µF
Pri coil is 7 turns of 1/4 inch copper pipe in a 45 deg. "fruit bowl" style.

Bridge is 4 40N60 driven by Dan`s 
interruptor/driver board, or by my own 555 interrupter from a midi keyboard.
I am going to use  Steve Connor`s driver later but for now, this will do.

I don`t use feedback yet either.

Supply is 310V from rectified 240V smoothed by 
3000µF lytic and bypassed by 2.5µF CD942`s

My impression is that the DRSSTC is easy to run, 
I have not yet fried any IGBT`s. When the primary 
circuit is tuned to 54kHz and I drive the 
oscillator at the upper split frequency,60kHz, 
ZCS snaps nicely into sync over the entire 200µS 
burst. At the same time the sound of the streamer 
tells me that the coil is operating well.

With one of those nifty Watt meters (boy do I 
wish someone will tell John Coture that they are 
available and good) I measure a power consumption 
around 750W when the coil is making 42" sparks at 200BPS.

At that time the primary current peaks at 600A 
and it does not appear to change even when the 
coil is producing ground strikes.

So untill now, I am pretty happy with DRSSTC 
coiling. The ability to trigger at TTL level, 
which it shares with the OLTC is sure handy. But 
it is a bit easier to build due to the lower 
primary currents. The fact that it plugs directly into the wall is really wild.