The self-excited homopolar generator. I. Theory and electrical design

The authors describe two types of self-excited homopolar generators which can be used to power an electromagnetic railgun. These are the single-rotating and contrarotating versions of the machine. A method is described for modeling both types of machine, and typical results are presented showing the performance of the overall system (generator and railgun). Results are also given for the performance of the current collection system and the stray field profile of both types of machine. The self-excited air-cored homopolar generator is shown to be an ideal power source for an electromagnetic railgun. It is capable of high overall efficiency, typically 40% for the complete system (generator and railgun), and gives an acceptably low peak/mean acceleration in the barrel. The single-rotating generator is much the simpler configuration mechanically, but the contrarotating machine has the advantage of eliminating the net torque reaction on the stator