Browsing by Subject "EM launcher"

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Design of a 600 MW Pulsed Air-Core Compulsator
(1990) Kitzmiller, J. R.; Faidley, R. W.; Fuller, R. L.; Headifen, R.N.; Pratap, S. B.; Spann, M. L.; Thelen, R. F.
The Center for Electromechanics at The University of Texas at Austin (CEM-UT) is currently in the manufacturing phase of a laboratory based small caliber electromagnetic (EM) launcher and air core compensated pulsed alternator (compulsator) power supply. The two pole, self-excited compulsator features significant component design advances which will allow operation at considerably higher energy (12.3 kJ/kg) and power densities than previously demonstrated. To accomplish this, the generator design features broad use of the current state of the art in materials solid state switching components, and extensive computer modeling. For example, the compulsator features a multilayer composite rotor operating at a tip speed of 530 m/s, silicon nitride ceramic shaft, and silicon nitride rolling element bearings mounted in stationary hydrostatic bearing dampers. Designed specifically for drivmg a small bore augmented railgun, the 750-kg compulsator will operate at 2.2 kV and provide a salvo of current pulses peaking at 386 kA during each discharge cycle. This paper describes the final design and predicted operating characteristics of the compulsator system. Overall system performance parameters are reported, including results from the optimization code used to aid in the design of the compulsator system. A system design overview is presented with emphasis on new materials and state of the art machine components to be used for the first time in a compulsator.
Synchronization of Multiple Pulsed Alternators Discharging into an EM Launcher
(IEEE, 2014-07) Pratap, S. B.; Zowarka, R. C.; Hotz, T. J.; Pish, S.; Murphy, B.
As the energy level in the projectile increases it becomes necessary to use multiple pulsed alternators discharging in parallel into the EM launcher. Another reason for having more than one machine is to compensate torque and gyroscopic effects of the pulsed alternator. This requires that machines be built in counter-rotating pairs. These machines are identical in all respects except for their direction of rotation. A study was conducted to determine how the machines can be motored so that they stay in lock step in speed and phase as they are motored to full speed. The methods of connecting these multiple machines are discussed. The aim of the connection scheme is to allow the machines to naturally stay locked in speed and phase throughout its operating range. Sensitivity of the performance of these machines to small variations in the machine parameters, which is to be expected in the machines, is discussed. Sensitivity of the discharge performance to small phase angle mismatches due to tolerances is also discussed. To verify the conclusions of the study an experiment was performed on two identical 50 kVA machines discharging into a low impedance load. The motoring system that is discussed in the study was implemented in this experiment which kept the machines in lock step. This motoring system is described. Thereafter discharges were made at various speeds and field current levels. Phase angle mismatches were introduced between the two machines to see how it affected current sharing. The results and conclusions of these tests are presented in this paper.