Hello there I need some (a lot of) help with my project. I've started to design a high efficiency multistage coilgun. The main feature of the design is using the self-inductance formed in coils that were shut down for accelerating the following coils. To perform this, we can divide each coil into 3 segments (lets call them subcoils), connected with a wire and power all them 3 with a single capacitor. At first, the current from the capacitor is flowing through all 3 segments and a projectile is being pushed through the first segment. Than the first sensor is being activated with the projectile and it switches the power flow to only second and third subcolis As the current in the first subcoil is changed, the self-inductance directed in the opposite direction is appearing. In theory, we can use this power to increase the current in the following segments. The same thing is happening between second and third segments. And I want to place 3 of this stages (9 subcoils in total) I will use 8mm caliber projectiles, 40mm or 50mm length. I chose 5200mkF 450V or 6800mkF 400V capacitors, 2 of them in parallel for every stage (6 capacitors in total) Yes, I know it sounds way too powerful, but that's my actual goal. It's not my own idea. I have learned it from here http://gauss2k.narod.ru/adf/gs3seg.htm (русские вперёд). So, some problems had appeared. I can't figure out how to properly calculate the required inductance of the coils. In the source it is said that the inductance of the first subcoil should be equal to two of the second and the third subcoils (L1=2*L2=2*L3) to achieve the best performance. Also, my rough estimates show that peak current through the coil will be about 1,5-2,0kA for 3,0-4,5ms. This is quite a lot! I'll have to manage this energy and choose the power switches rightly. To sum up, I will be glad to hear your opinions about this idea. It's kind of controversial, but I hope it's not a certain failure.