Alpha-DR Mark II


Due to the experience acquired in the Alpha-DR Twins project, in 2020 I decided to improve it. Meet Alpha-DR Mark II!


  • Driver: Mini-DDR (includes phase-lead, over current detection, undervoltage-lockout, tOn limiter, DTC limiter and thermal shutdown)
  • Power Supply: 220VAC full wave rectified mains, closed-loop automatic pre-charge + line filter
  • Bridge: BSM150GB60DLC IGBT’s Full-Bridge
  • DC BUS: Laminated, 1oz copper PCB + solder reinforcement, 1x 400V | 2.7mF BUS capacitor + 2x 400V | 1.5uF decoupling capacitors
  • Resonant capacitor: 6kVDC | 73.3nF MMC, 30x WIMA MKP10 2kVDC | 22nF film capacitors, 3s10p
  • Primary coil: Flat, 9 turns of 6mm^2 wire, tap at 8.5 turns, 3/8″ aluminium tubing strike ring.
  • Secondary coil: ~1400 turns, 100x341mm PVC form, 333mm winding, 31AWG. Polyurethane and epoxy coated.
  • Top load: 355x105mm solid toroid, 576 flat surfaces, 3D printed frame covered with aluminium tape, PU coated
  • OCD: Set at 340A
  • CTs: 2x 1:30:15 = 1:300 cascade, same ratio for OCD and feedback
  • Resonant frequency: ~142kHz
  • On-time: Up to 150us
  • Duty-Cycle: Up to 10%
  • Thermal protection: 50ºC
  • Enclosure: 18x18x14 (cm), 3D printed frame (PETG) + acrylic
  • Height: 68cm
  • Streamer lenght: Up to 1.20m, measured in a straight line.

    To be continued…

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