Author : National Aeronautics and Space Adm Nasa
Publisher : Independently Published
ISBN 13 : 9781729367131
Total Pages : 62 pages
Book Rating : 4.3/5 (671 download)
Book Synopsis Lightweight Linear Alternators with and Without Capacitive Tuning by : National Aeronautics and Space Adm Nasa
Download or read book Lightweight Linear Alternators with and Without Capacitive Tuning written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-28 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Permanent magnet excited linear alternators rated tens of kW and coupled to free-piston Stirling engines are presently viewed as promising candidates for long term generation of electric power in both space and terrestrial applications. Series capacitive cancellation of the internal inductive reactance of such alternators was considered a viable way to both increase power extraction and to suppress unstable modes of the thermodynamic oscillation. Idealized toroidal and cylindrical alternator geometries are used for a comparative study of the issues of specific mass and capacitive tuning, subject to stability criteria. The analysis shows that the stator mass of an alternator designed to be capacitively tuned is always greater than the minimum achievable stator mass of an alternator designed with no capacitors, assuming equal utilization of materials ratings and the same frequency and power to a resistive load. This conclusion is not substantially altered when the usually lesser masses of the magnets and of any capacitors are added. Within the reported stability requirements and under circumstances of normal materials ratings, this study finds no clear advantage to capacitive tuning. Comparative plots of the various constituent masses are presented versus the internal power factor taken as a design degree of freedom. The explicit formulas developed for stator core, coil, capacitor, and magnet masses and for the degree of magnet utilization provide useful estimates of scaling effects. Niedra, Janis M. Unspecified Center...