Browsing by Subject "induction motor"
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Item An Approximate Model for Studying Harmonic Current Amplifications in Current- Source Inverter Fed Induction Motor(IEEE, 1992-12) Hsu, J.S.;The nature of harmonic current amplification in current source inverter fed induction motors is studied through a six-pulse current source inverter. An approximate model consisting of the induction motor and the parallel and series capacitors was used to simulate the circuit under the multiple commutation mode. The thyristor currents were treated as the source currents. The analytical result shows that the steady phase harmonic current amplification of the six pulse inverter-fed motor goes from the high frequencies down to the fifth order of the harmonic when the values of the capacitor reactances of the approximate model are reduced. The experimental study showed that the fifth harmonic current amplification was significant under a multiple commutation modeItem Design and stress analysis of a high speed rotor for an advanced induction motor(2004-01) Caprio, M.T.; Lelos, V; Herbst, J.D.This paper presents the particular mechanical design considerations and analysis results relating to an induction motor rotor designed specifically for high-speed, power dense, mobile applications. A unique end ring design is presented which balances the mechanical and electrical requirements of the high-speed, high-temperature design. Specification of core lamination material is treated in the context of managing spin stresses and maintaining radial contact pressure over the broad operating speed range. Analysis of the rotor bar extension configuration is described to accommodate the relative growth between the end ring and laminated core at operating speed and temperature. A low temperature joining process for the bar / end ring connections is presented that maintains the strength properties of the age hardened copper alloy materials of the squirrel cage assembly.Item Induction Motor for Wide Range Static Inverter Drive: Electrical Machines, Designer's Point of View(1983-03) Driga, M.D.;A fact, usually overlooked in technical papers is that the design of electrical motors in a.c. drives is highly dependent on the parameters and construction details of the power supplying steady-state conversor, especially on the harmonic content of the applied voltage. The paper outlines some ways of making the motor less sensitive to such harmonics, even when it drives a shaft which is suspended on active magnetic bearings. Attention was shifted from the inverter design to the induction motor design, to ways and means of making the motor immune to changes from one type of inverter to another. The solutions presented are the result of design, manufacturing and extensive testing of a series of induction, squirrel cage electric motors, used in high performance machine-tools (boring and grinding precision machines) with rotating speeds up to 42,000 rpm, with speed control by continuous speed variation. Ratings of electric motors were 0.4; 1.1; 2.2 kw.Item Nine-Phase Armature Windings Design, Test, and Harmonic Analysis(IEEE, 2005-05) Jordan, H.E; Zowarka, R.C.; Pratap, S.B.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 nine-phase winding exhibited a very low harmonic content, a distinct advantage of a nine-phase winding for future applications.Item Transient 3-D thermal analysis for an air-cooled induction motor(IEEE, 2005-05) Liu, H-P.; Lelos, V.; Hearn, C.S.For an induction motor that is cooled by an airflow ventilated across the air gap between the rotor and stator, the rotor end-ring and stator end-turn cooling might influence the motor temperatures in the core sections appreciably. Detailed motor thermal modeling is typically required to provide transient rotor temperature distributions for rotor structural analysis and to predict stator temperature distributions to assure the maximum stator temperature is below the stator insulation temperature limit. For an air-cooled induction motor, transient 3-D finite element thermal analyses for both rotor and stator have been performed in this paper. In the stator thermal model, the slot conductors and various insulations were smeared and equivalent thermal properties were used to reduce modeling and computational effort. Position-dependent and time-dependent air cooling boundary conditions, which include air temperatures and forced convection heat-transfer coefficients, were applied to the 3-D thermal models