Improvements&explanations after the break!
ImprovementsThere are several aspects to improve apon a quick and simple coil.
- has high switching losses. The resistance of the coil leads just touching the cap is likely to be higher than the resistance of the coil.
- hasn't got the best turns number.
- has too thick a barrel. The gap between the coil and the armature should be as thin as possible.
- suckback. A reduction in speed after passing the coil's midpoint, due to a remaining magnetic field. This can be avoided with timing changes.
- back EMF. Any energy that isn't put into waste heat or the armature will come back to the capacitor. Unfortunately, it will come back with the opposite voltage, which many capacitors don't like.
- eddy currents. The sudden surge in magnetic field induces currents in any conducting parts of the coilgun. This wastes power.Eddy currents in the projectile are doubly bad since they also repel the projectile.
- The coil I used has 250 turns.
- The enameled wire has an diameter of 1,0mm. Originally it was used for audio appliciations but due to its perfect size I used it for the coilgun.
- The projectile is basically a sawn off piece of a metal screw.
The reloading mechanism:
Theres a little magnet on top of the green pin. The magnet holds the projectile in position.