Design of Low-Current High-Efficiency Augmented Railguns

Abstract

Properly designed augmented railguns (ARGs) can operate at significantly lower currents and higher efficiency than conventional non-ARGs. This paper analyzes the performance of a two-turn and a three-turn ARG showing the design parameters that are needed to achieve low-current high-efficiency operation. The ARG of this paper has a 40-mm square bore and is 820 mm long. Typical operating currents are from 150 to 300 kA with pulsewidths of approximately 6 to 8 ms. Projectile mass is typically in the range of 130 to 400 g. Projectile velocity is variable from 50 to 250 m/s. Experimental performance is compared with the theoretical predictions of the recently developed electromagnetic launcher (EML) equation. There is a good agreement between measured efficiency and theoretical predictions providing further confirmation of the EML equation. Deviations between measured efficiency and theoretical predictions are attributed to a poor sliding contact. The data also provide further evidence of the recently reported velocity-skin-effect in the contact.