The Rotary Flux Compressor--A New High-Power Compact Energy Store

Capacitors and explosives are the only devices that are traditionally used for storing energy for long periods of time when the need exists to release this energy very rapidly, at very high powers. Rotary energy stores, e.g., flywheels, are also capable of storing energy for reasonably long times (i.e., tens of minutes), but until recently, the minimum discharge times for these stores have been the order of a tenth of a second. This paper discusses a new rotational energy store, the rotary flux compressor that has produced high power electrical discharges of less than one millisecond in duration. Computer codes have shown the feasibility of machines that will deliver up to 15 megajoules in single or multiple sub-millisecond impulses. Several types of rotary flux compressors exist, including the Compulsator, the Active Rotary Flux Compressor (ARFC), and the Brushless Rotary Flux Compressor. The ARFC is currently under development at LLNL and the University of Texas. It requires startup energy (via a capacitor), but tests to date demonstrate 15 times more energy delivered by the machine than is stored by the startup capacitor. This paper discusses the conclusions drawn from these tests.