Due to the experience acquired in the DRSSTC III large tesla coil project, in 2021 I decided to improve it. Meet DRSSTC IV


  • Driver: DDRX by Franzoli Electronics, based on Steve Ward’s UD2 (includes phase-lead, overcurrent detection, undervoltage-lockout, tOn limiter, DTC limiter and overtemperature protection)
  • Power Supply: 3-phase voltage doubler with automatic pre-charge by Franzoli Electronics, 220V(AC)in, 620V(DC)out, up to 11kW
  • Bridge: CM300DY-24NF IGBT’s Full-Bridge
  • DC BUS: Laminated, splitted in half, 2mm thick aluminum plate. 1kV | 6mF (4x 500V | 6mF electrolytic capacitors, 2s2p) BUS capacitor bank, 1.1kV | 80uF (2x 1.1kV | 40uF film capacitors, 2p) decoupling capacitors
  • Resonant capacitor: 12kVDC | 0.68uF (36x 2kVDC | 0.68uF film capacitors, 6s6p) resonant capacitor bank, 168ARMS rating
  • Primary coil: Flat, oil cooled, 10 turns of 3/8″ copper pipe, tap at 8.2 turns, 1/2″ aluminium tubing strike ring, covered by 5mm thick acrylic plate
  • Secondary coil: ~2400 turns, 250x1100mm PVC form, 1070mm winding, 26AWG. Polyurethane and epoxy coated
  • Top load: 1120x275mm skeleton toroid, 13x 1/2″ aluminium tube rings, 3D printed frame
  • OCD: Set at 1kA
  • CTs: 2x 1:40:25 = 1:1000 cascade, same ratio for OCD and feedback
  • Resonant frequency: 34.96kHz (primary)
  • On-time: Limited at ~600us
  • Duty-Cycle: Limited at ~16%
  • Thermal protection: NTC thermistor, schmitt-triggered 9ºC hysteresis On/Off control (55/41°C)
  • Enclosure: 410x410x295 (mm), 20mm T-slot aluminium profiles + 5mm thick acrylic plates.
  • Height: 207cm
  • Streamer lenght: Up to 3.60m, measured in a straight line.

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