Performance Analysis of Passive Compulsators with Different Field Current Densities used for EML Applications

Abstract

In passive compulsators, compensation is provided in the form of conducting shield which is placed in the vicinity of armature conductors. Due to compensating shield, the effective airgap between the stator and the rotor in the iron core compulsator increases as the shield is made up of non-ferromagnetic material. This puts the limit on the maximum possible magnetic flux density in the air gap. To optimize the performance of the compulsator, the magnetic flux density in the air gap should be as high as possible. There are two ways to achieve this: (1) reduction in the thickness of the shield and (2) increasing the excitation field current density. First case has already been analyzed by the authors and the results are presented. In the second case, the requirement of the rotor excitation becomes high. In this paper, the second case is evaluated and a number of designs were simulated, analyzed and optimized for a given set of design variables and the performance was compared with the first case. Peak current resulting from the compulsator, final velocity of the projectile, electromagnetic torque on the compulsator, tangential and radial forces on the armature conductors are the parameters analyzed. At the end, performance of a design with high nominal field current density is compared with the performance of the design with low thickness of compensation shield for the same magnetic field seen by the conductor.