Abstract--Performance testing of the model-scale CPA was recently completed at the University of Texas Center for Electromechanics. A major part of the project was the development of design and simulation codes that would accurately represent the performance of pulsed alternators. This paper discusses the components of the system and its operational sequence. Details of the performance simulation model are presented along with test data. The test result is compared to the predicted data.

The electromagnetic powder deposition (EPD) system employs high velocity gas flow to accelerate powder material to conditions required for high strength plating. The gas flow, however, is not continuous; rather it consists of bursts generated by an electromagnetic railgun and pulsed power system. Each gas burst is created by a high pressure plasma arc which fills a transverse section of the gun. This current carrying arc is driven by the railgun Lorentz force (magnetic pressure) and acts much like a piston, which via a snowplow process accelerates and compresses an ambient gas column to the flow speed required to accelerate powder particles. Analysis of the total system was carried out to provide scaling relations which give guidance in design of the system. Plating considerations define a desired powder velocity; this combined with the choice of working gas and ambient pressure determines the velocity and duration of each gas burst. Selection of gun geometry completes the definition of the pulsed power system requirements. An outline of the analysis is presented along with the physical models used.

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This paper describes the diagnostic tools used in the development of a new electromagnetic powder deposition system. The instrumentation, interpretation of data, and subsequent decisions regarding the direction of system development are discussed. Important system parameters, their impact on system performance, and techniques to measure them are presented. The electromagnetic powder deposition system is based on railgun technology developed by the Department of Defense. The system drives an ionized plasma sheet down the length of a railgun, reaching a final plasma velocity of 4 km/sec. The high velocity plasma, in turn, snowplows [1] a shock compressed gas column in front of it. This gas column sweeps through a powder cloud and accelerates it by viscous drag to a final velocity of 2 km/sec. Important system parameters include particle velocity, gas velocity, gas column pressure, and plasma propagation and velocity. Diagnostic tools include pressure transducers, a high speed digital framing camera, fiber optics and magnetic probes.

Abstract-A nine-phase armature winding was developed for a large generator. Alternative methods for interconnecting the pole-phase groups were examined. An alternate-pole connection scheme was adopted and a prototype induction motor was constructed to confirm the winding scheme.Since only a three-phase power source was available for testing, the induction motor was tested by using three, three-phase winding sections, one at a time.Air-gap harmonic fields produced some unusual results. These test results and harmonic analyses to explain them are presented herein.The tests confirmed the nine-phase winding scheme that was adopted. The harmonic analyses revealed that the complete ninephase winding exhibited a very low harmonic content, a distinct advantage of a nine-phase winding for future applications.