I just tried the Bourns PM61300-1 and PM61300-2 transformers based on the lead given above. They give plenty of voltage, as expected, but seem short on current capacity. My test setup used a 0.47 microfarad capacitor for the HV discharge, a coil from a Zenoah G62, and two different oscillator circuits. One of the circuits was from a popular commercial imported unit. Charge voltage was to around 350 V and the oscillator was fixed at 60KHz as per the datasheet. (The commercial unit used a voltage doubler output, so I had to modify that to a full bridge to keep the voltage below 500V.) Also tried higher and lower oscillator frequencies, but with no improvement. I could get good sparks, but could not go above 6000 to 8000 rpm reliably in simulation due to the low current capacity. Also tried a higher voltage, but was limited to about 400V by the components.

Does anyone have any other source of commercial transformers to recommend? I can adapt the cricuit to use transformers with either a singler primary winding or a primary with the second, feedback winding.

John