This part of my site describes the work I am doing on the Dual Resonant Solid-State Tesla Coil. I developed a PLL driver with current limiting, and discovered a special tuning (only possible with the PLL driver) that stops primary current running out of control on ground strikes. I built the Mjöllnir experimental coil using these ideas, and so far it hasn't blown any IGBTs, although it has operated at 5 times the power and 10 times the bang energy it was designed for, and burnt up its secondary coil twice from flashovers. It was successful enough that I decided to build a scaled-up version called "Odin The All-Fragger".

For more DRSSTC information, check out these other great sites-
Steve Ward operates the world's most powerful DRSSTC
Jimmy Hynes made the first ever
DRSSTC.COM by Terry Fritz
Dan McCauley another DRSSTC pioneer

Initial messing around

Initial messing around
DRSSTC modelling
Further experimental work

Testing the new PLL driver

Testing with single resonator
Testing with dual resonators

The Mk2 PLL driver and accessories

Please read the PLL system docs for explanations of how these
circuits work. PCBs are available to buy for the main PLL driver
board and the IGBT brick drivers.

The schematics below show what's in the "Mjöllnir" DRSSTC.

Driver board schematic sheet 1
Driver board schematic sheet 2
Driver board schematic sheet 3
Dee-Lux Interrupter schematic
"Solid-state variac" board schematic
H-bridge, current sensor, and SCR regulator schematic
EAGLE board and schematic files + BOM (115k zip)

After building Mjöllnir I revised the PLL driver board and
designed an IGBT brick driver add-on for
Odin The All-Fragger.
EAGLE board and schematic files for Rev. B
IGBT brick driver schematic
Brick driver power supply schematic
Docs for PLL system Rev.B (123k PDF)

Building Mjöllnir* the experimental coil

Primary coil and current sensor
Secondary coil and driver board
The build continues
Appearance at Derby 2005 (links to roffesoft.com)
Primary needs modifying
Appearance at Cambridge 2005 (links to roffesoft.com)
5ft spark at Cambridge 2005

Spark pictures

spark pics
First light, flashovers
More sparks


Bang capture with DSO
Efficiency experiment 1

I start work on Odin The All-Fragger

IGBT brick
Prototype IGBT brick driver
Read more about O.T.A.F. on 4hv.org...

*Mjöllnir was the name of Thor's hammer that he used to forge lightning bolts (afaik)
So it's almost like calling your coil Thor but not so cliched.
I think I'll call the next one "Odin The All-Fragger"

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