Coilgun driven by commercial power supply

Summary form only given: The coilgun accelerates a projectile by the magnetic force produced from a current-carrying coil and the various applications of it are possible. The principle of coilgun is as follows: As a current flows through a coil, magnetic field is generated. If there is a magnetic material near the coil, it is magnetized and attracted to the coil. The projectile is accelerated to the center of coil. If the current is interrupted before the projectile arrives at the center of coil, the projectile is launched from the opposite end of coil. The advantages of coilgun are as follows: The projectile is launched contactless, so the lifetime of the apparatus is long. No sound is produced when the projectile is launched. On the other hand, low energy conversion efficiency is the disadvantage of coilgun. Therefore, the coilgun is useful for moving a heavy load slowly, although large scale experiments to pursue high velocity have been carried out. In general the coilgun is driven by capacitors or flywheels. With a view to applying for a low-velocity impact testing machine, we have examined the fundamental characteristics of coilgun directly driven by commercial power supply. Six sets of experiments were carried out. First, the same projectile was launched using three coils. Then the velocity of projectile was measured. Second, three projectiles were launched using the same coil. The lengths of three projectiles are same but the diameters of them are different. Third, three projectiles were launched using the same coil. The lengths of three projectiles are different but the diameters of them are same. Fourth, the same projectile was launched using the same coil as the halfwave number of applied voltage is changed. Fifth, the time at which the projectile reached certain points from the onset of voltage application is measured using a photo diode and a He-Ne laser. Then the behaviors of the projectile are examined. Sixth, the time at which the projectile started - o move from the onset of voltage application is measured using the same method of fifth experiment. We have successfully launched the projectile from the coilgun directly driven by commercial power supply and have completed the study of the fundamental characteristic of a single coilgun. To increase the velocity of the projectile we have attempted to examine a multistage coilgun.