EE-Core Ferrite HV Tranformer 50-70 kV

[Patrick]

Restarting my old project.

Previously as many of you know I had long threads (many of you helped enormously) on 4HV.org on conventional ferrite and planar ferrite transformers and modes of driving them.
Resuming but with this new design:

Ferrite:         "TSC-50 ALL", EE. "TSC International" (See attachment)
Primary:       32 turns, 7 strands 28 AWG, printed coil form.
Secondary:   5000 turns, 1 strand, 38 AWG, 10 banks, printed form, low side grounded.
Insulation:    Silicone or Mineral oil drawn by vacuum and Kapton non-adhesive film, liquid-tight container.
Input:          24-48 V, 200-400 Watts. 75 kHz, pulse-by-pulse current limit, MOSFET full bridge.
Output:        50-70 kV,  80% Duty Cycle @ 300 W. (External CW option.)

Here are some pics to start with:

[davekni]

Have you measured self-resonant frequencies for your transformer?  Is your 75kHz operating frequency near either resonant frequency?  Is the 50-70kV AC from transformer or DC after rectification (or after voltage multiplier)?  If AC, would be far above simple turns ratio, so imply running at upper resonant frequency (series resonant frequency where secondary winding and output lead capacitance resonating with secondary leakage inductance).

[Patrick]

AC and DC are being attempted, with and without voltage multipliers and yes, a significant arsenal of instrumentation will be aimed at this device.