MINI DRSSTC

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I have just discovered that my little IGBTs (BUP 307/314) can work at higher frequencies and decided to build my own mini DRSSTC. It would be easier to transport and display and the long sparks from a small coil would look good. The single other mini DRSSTC I am awared of are:

RayeR mini  DRSSTC

Reaching miniDRSSTC (with IRFP460 h-bridge and primary feedback)

Steve Ward mini DRSSTC

The results are quite good (21-22 inches streamers from a 4.32 / 10.8 inches secondary). Target is put at 24 inches from toroid.

PICTURES        ON TIME = 1 msec, PRF = 5-30 pps

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ON TIME =  msec, PRF = 1-5 pps   At low PRF the coil outputs streamers from nail and toroid too

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SCHEMA ( it is the miniSSTC schema of Steve Ward with a few differences)

SYSTEM PICTURE

SECONDARY:    4.32 inches diamater, 10.82 inches wound lenght, 1375 turns with 0.2 mm                               magnet wire, grey PVC pipe, Ls= 69107.47 uH, Cself= 5.8956 pF                              Fres without toroid= 249.46 kHz                                              TOROID:             a little one of 11.77 pF F res with toroid: 157.86 kHz PRIMARY :          4 or 3 turns close wound, trifilar (3x2.5 mm), 3 cm clearence                                between pri-sec, low coupling                                                                         Np                        Lp                             Cp                                       4 turns               5.08 microH                 200 nF                                       3 turns               4.06 microH                 250 nF DRIVER:            antenna feedback, 1N4148 clamping diodes, 74HC14 hex inverter (5V)                              UCC inverter and non-inverter driver chips (15V), clamping diodes                              (1N5819) on the UCCs output, 4.4 uF coupling cap with the gdt                                           GDT:                   13 turns 1:2:2  30 V on IGBT gates HALF BRIDGE:    2 BUP 307 (1200V @ 35A) each on its own heatsink, protected with                               antiparallel diodes MUR3060, 33 V@1 watt back to back zenners on                                gates, 5.6 ohms dumping gate resistors, 2.2 uF caps on the cap divider                              full rectifycation with a 1000V @ 35A bridge, a single 470 uF@400V                               DC bus cap                                            INTERRUPTOR:   R on = 1-10 kohms, R off = 10 kohms- 3 Mohms, C = 1 uF                                On time = 1 msec,  PRF= 10-50 pps                                      No noise generator used to start oscillation (555) Ground = water pipe Voltage input control with a variac (0-220 vac input).

PRIMARY PICTURES

BRIDGE-DRIVER PICTURE