Dave Gambles Coil Specifications Model 1 Primary: 10 turns flat spiral 8mm copper heating tube (tapped around turn 6) Secondary: 500m of 7/0.2mm insulated cable wound on 7" gas main pipe and varnish coated Winding Length of 115cm Effective winding spacing of 1.25mm due to insulation Effective L=21.2mH Top load: Car inner tube covered in gaffa tape and aluminium foil "Split" design avoiding shorted turn Dimensions 43cm major diameter, 12.5cm minor diameter Effective C=19pF Fres: 180kHz Tank cap: 50nF 21kV MMC (98 x 0.1uF 1.5kV LCR caps from Farnell) PSU: DC resonant charge using twin MOT transformers DC link voltage 10kV (voltage doubling rectifier) DC link capacitor is 8 MOCs in series/parallel giving 0.5uF at 10kV Charge inductor is two MOT secondaries on modified (gapped) cores giving 8H total Rectifiers and resonant charge diodes are series connected MODs Final tank cap charge voltage = 20kV due to resonant charge Gap: DC motor powered rotary gap with 4 bangs per revolution Maximum bps is 400 Electrodes are 3mm brass rod Configured for shortest gap route (i.e. 2 air gaps in circuit) Supply: Single phase 230V AC at <15A Power: 3kW maximum at 260V input and 400bps Control: 8A Zenith variac Arc length: 1.8m (6 feet) Model 2 (In development - figures approximate) Primary: Remotely tuned dual flat spiral Secondary: As model 1 Top load: As model 1 plus one larger toroid Fres: As model 1 Tank cap: 50nF 70kV Hivotronic pulse cap PSU: DC resonant charge using quad MOT transformers DC link voltage 20kV (voltage doubling rectifier) DC link capacitor is 48 22uF/450V caps in series giving 0.46uF at 21kV Charge inductor is four modified MOT secondaries on small cores giving 6H total Rectifiers and resonant charge diodes are series connected 1N5408s + speed up parts Final tank cap charge voltage = 40kV due to resonant charge Gap: As model 1 Supply: Single phase 230V AC at <30A Power: 6kW maximum at 260V input and 400bps Control: Electronic 30A Variac (in development) Arc length: 2.7m (9 feet) expected!