DRSSTC
Dual resonant solid state Tesla coil
Dual resonant solid state Tesla coil
A DRSSTC tunes the primary as well as the secondary and drives it in bursts, so the current in the tank is measured in hundreds of amps while the average power stays modest. That trade is what makes the timing questions sharp: a switch that opens in the wrong part of the cycle turns the whole design into a heater.
tap any part
duty 3.60 %
Every part of the diagram answers for itself. Pick one.
DC bus
- start heresafety
DRSSTC safety: what in a Tesla coil will actually kill you
Not the arc. The things on this page are at DC or mains frequency, they are inside the cabinet, and they do not announce themselves.
- start heresupply
The DRSSTC bus capacitor bank: loop, ripple and the volts it sees
The microfarads are arithmetic and take an afternoon. What ends a bank is the loop it sits in and the volts it actually sees.
The bridge
- start herepower stage
DRSSTC switches: IGBT, MOSFET or SiC, and what each one costs
One choice that sets both the frequency you can run and how long the bridge lives. Three families, and what each of them makes you pay for elsewhere.
- power stage
The DRSSTC bridge: half or full, layout, paralleling, what kills it
Peak temperature is not the mechanism. The size of the swing tears bond wires over thousands of cycles, a long way below anything on the datasheet.
- timing
DRSSTC ZCS against ZVS, and whether a snubber helps or costs
Turning off exactly at the current zero reads like the ideal and is the opposite. The residual current is what commutates the node, and late kills while early only heats.
- power stage
DRSSTC voltage margin is in the loop, not on the bus
The bus is the one voltage in a bridge that nothing is actually stressed by. What the silicon stands off is the bus plus whatever the copper around it adds, and that gets measured at thirty volts.
- power stage
DRSSTC IGBT pulse ratings: the datasheet number is a temperature
An IGBT's pulse current rating is a sentence about heat with the heat left out. How hot you are willing to arrive is a decision, and the two published answers sit a factor of three apart.
- power stage
What the record says a DRSSTC brick IGBT will take
Thirty two published machines that held and three that did not, tabulated by one person. Run the two lists against each other and the idea that a switch has a frequency and a current it can take does not survive: one part is on both lists at the same operating point, from the same builder.
Gate drive transformer
Driver
- start herehow it works
What a DRSSTC driver does
Four jobs on one board. Without it the power section is a box of parts, and the frequency it has to find is not a number you can set once.
- driver design
DRSSTC phase lead: what it is made of, which inductor to fit
A driver that fires on the current zero is already late. The lead is how you pay that back. What it is made of, which coil delivers it, and the three worries about that coil that turn out to be unfounded.
- driver
The UD DRSSTC driver boards: which revision you are holding
The logic core did not change from 2.1 to 2.7, so modifications transfer between revisions. The part designators do not, and that is what wrecks a repair.
Interrupter and modulator
- start herecontrol
The DRSSTC interrupter: bangs per second, ontime and duty
Bangs per second is the frequency of the note in hertz. There is no best rate, only a note, and two settings on this box kill transistors.
- safety
The DRSSTC fibre link, and the fail-safe rule
A broken fibre must turn the coil off, and the receiver does not do that by itself. Its output is defined in the dark, and on the reference board that input is held at on.
Current transformers
- start herehow it works
What a DRSSTC current transformer is, and what it senses
A ferrite ring on one of the thick conductors. It is how the driver finds out what the tank is doing, and it is the only sense the machine has.
- protection
DRSSTC overcurrent protection: OCD, pulse skip and why it fails
Nothing limits the primary current in a doubly-resonant coil. Test the actual threshold rather than the position of the knob, and start it low.
- tuning
Tuning a DRSSTC by the shape of the primary current envelope
The primary current across a whole bang is the only tuning evidence a loaded QCW gives you, and it is coarser than it looks. It finds the pole and the runaway, not how far to move the tap.
- instruments
Scoping a DRSSTC without killing the scope
More equipment dies at the bench than in the arc. Never float the scope: it stays earthed and the isolation goes on the circuit under test.
Tank capacitor
Primary
- start herehow it works
What a DRSSTC primary is for
A few turns of heavy copper that are not connected to the secondary anywhere, and are not trying to be.
- tank design
DRSSTC coupling: how far above critical, and what raising it buys
Wind the primary tighter and the arc gets longer. It is the first thing anybody tries, and the record holders run the loosest coupling on the list.
- tank
DRSSTC primary design: impedance, turns and detuning
Nobody sets the primary current. It comes out of a division, and the number you actually choose is the impedance of the tank.
- tuning
DRSSTC tuning: the two poles, and which one the driver lands on
Couple a primary to a secondary and the resonance splits in two. The frequency you carefully measured is a mode that no longer exists.
Secondary
- start herewindingin SSTC
How to wind and measure a Tesla coil secondary for an SSTC
Not a transformer winding that happens to be long. Almost everything that goes wrong with one goes wrong because it was wound as though turns were the point.
- failure
What a ground strike does to a DRSSTC
One event, five consequences, and the mild strike is the one that moves the machine to the wrong mode.
- resonator
A DRSSTC magnifier is not just a longer coil
Three coils and two couplings, argued for on the coupling the driver can hold. The one head-to-head with figures made less spark per inch of winding than its builder's own two-coil machine.
Topload
Breakout point
- start herehow it works
What a DRSSTC breakout point is for
It looks like an afterthought and it is one of the few parts you can actually aim the discharge with. Short beats long, and it is a consumable.
- first run
DRSSTC no sparks or short sparks: what to check, in what order
The order to look in, and the order matters: the cheap checks are also the ones that are usually wrong, and none of the three classic causes is a tuning problem.