Pulse power > Induction Launchers, Coil Guns and Rails guns

Simplified mutli-stage coilgun idea

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Scicat111:
Here is a coilgun concept I came up with (and the accompanying thought processes), however I am looking for some input from someone more experienced in the field before comiting to it:
Thyristor switches are hard to use in reluctance designs since they cannot be turned off; this results in either extremely high optimisation requirements for the capacitor bank, or the use of MOSFET switches- those, however, have to be switched on, held in that state, then switched off again- which results in rather complex electronic circuitry.
Since inductance coilguns don't really care when the coils are turned off, would it be possible to use a simple [sensor-thyristor-capacitor-coil] circuit for a multistage design?
One thing which bugs me is that I haven't been able to find any homemade inductance coilguns, wondering whether there is an inherent drawback with them (other than higher power requirements).

johnnyzoo:
I haven't seen many inductive coilgun designs on the internet. Most of them are disk launchers that have a single flat coil.

Multi-stage design should be possible and it might actually be easier than designing a traditional multi-stage reluctance coilgun. Worth trying definitely.

Scicat111:
ok, it took some time to get my power supply running, but there are some updates /and a rather unfortunate hurdle/ to report; the hurdle being that I have, regrettably, failed to find any concrete metrics to work with when it comes to current, capacitance, and even voltage required to get a thomson-style inductance coilgun (the injector stage) off the ground. During my ~250V test, a thyristor rated at 300A (2N6506G) was (literally) cracked in half, from which I assume the power has reached the required limit- and the projectile apparently failed to notice. Any base requirements for this system would be greatly appreciated, since as of now I am left with the theory that the small dimensions (3mm OD; 1mm wall) of the copper projectile are in some way detrimental to the thing working as intended (it is a long shot, but I have sort of run out of ideas)

davekni:
For such a tiny 3mm conductive (not ferromagnetic) projectile you will need a very short high-power pulse.  Thyristors will struggle with the required current rise rate.  Most are specified in the range of 50 to 150A/us.  They burn out if current rises faster.  (Can be pushed a bit for home use if the gate current pulse is high, ie. 1A instead of the minimum 50mA or whatever.)

Here's a video of my little penny-launcher project, 19mm diameter disks using a BTA16 TRIAC switch in the finished version:
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Scicat111:
ok, updates: i managed to cook the thyristor cell I was using (2* 2n6506g in parallel); found BTA41-600 triacs (on ebay, yay)- however, I managed to fry 2 of those in parallel (should withstand 800A) at ~280V of charge (430 muF capacitor, 450V max)- and, even so, got worse performance than with the old thyristors. not sure what to do, my 2 working theories are: A) the lower R of triacs permitted higher currents, which meant the setup as a whole was limited to lower power (capacitor charge)- which degraded the performance (in particular the length of the pulse) and in the end fried the triacs. working theory B is "don't buy critical parts from ebay"- this has a problem however, as all my other ebay electronics works well- and the triacs do too, until the capacitor banks gets above 250V.

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