Research on energy conversion efficiency of helical coil electromagnetic launcher
During operation of electromagnetic launcher (EML), the electric energies from power supply are mainly converted to the magnetic energy in the launcher, joule heat loss and the kinetic energy of armature. The magnetic energy in helical coil electromagnetic launcher (HEML) are not only consumed by the muzzle arc but also lost in commutation process. The magnetic energy loss in commutation process, joule heat loss in armature acceleration process and the cause of arc are investigated in the present article. The kinetic energy conversion efficiency of HEML, typically greater than 50%(Lc'/M '<; 1) which explains the high efficiency of HEML, is obtained. It is related to the length of the launcher, the greater the length, the higher the efficiency. The energy conversion efficiencies of HEML under zero current and constant current exiting modes are deduced. The longer acceleration length, higher current and mutual inductance gradient result in higher velocity, less joule heat loss and higher efficiency. The mutual inductance gradient and energized coil resistance are important to the energy conversion efficiency.