Some aspects of space and time harmonies in squirrel-cage induction machines
Some aspects of space and time harmonies in squirrel-cage induction machines
Time harmonics in the supply waveform of induction motors cause them to have additional losses and noise. These effects are generated by additional harmonic components in the flux distribution and in the rotor and stator current of the motor. The mechanism of their generation is explained. Available methods of analysis of induction-motor fields are compared, and a simplified approach to field harmonics is outlined. The flux components observed at stator and rotor are classified, and their relative significance in producing loss is examined experimentally for both a sinusoidal supply waveform and a waveform containing one additional time harmonic. The distribution of flux and rotor current harmonics is measured at sinusoidal excitation and for various points of machine operation. Results of measurements on the 50 Hz mains and for supply, frequencies ranging between 5 Hz and 100 Hz are presented. It is shown theoretically and by experiment that this frequency response of the flux distribution, if obtained for various supply voltages and load currents, can be used to compose the flux distribution found at any load and any periodic supply waveform. The principle of superposition which is involved in this procedure is shown to be valid for the induction motors tested and the influence of saturation can be neglected. Some suggestions for future experiments on time harmonic effects in induction machines are made.
University of Southampton
1976
Schmid, Eberhard
(1976)
Some aspects of space and time harmonies in squirrel-cage induction machines.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Time harmonics in the supply waveform of induction motors cause them to have additional losses and noise. These effects are generated by additional harmonic components in the flux distribution and in the rotor and stator current of the motor. The mechanism of their generation is explained. Available methods of analysis of induction-motor fields are compared, and a simplified approach to field harmonics is outlined. The flux components observed at stator and rotor are classified, and their relative significance in producing loss is examined experimentally for both a sinusoidal supply waveform and a waveform containing one additional time harmonic. The distribution of flux and rotor current harmonics is measured at sinusoidal excitation and for various points of machine operation. Results of measurements on the 50 Hz mains and for supply, frequencies ranging between 5 Hz and 100 Hz are presented. It is shown theoretically and by experiment that this frequency response of the flux distribution, if obtained for various supply voltages and load currents, can be used to compose the flux distribution found at any load and any periodic supply waveform. The principle of superposition which is involved in this procedure is shown to be valid for the induction motors tested and the influence of saturation can be neglected. Some suggestions for future experiments on time harmonic effects in induction machines are made.
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Published date: 1976
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Local EPrints ID: 462838
URI: http://eprints.soton.ac.uk/id/eprint/462838
PURE UUID: 2cfeaff6-d237-48ff-a95b-0b5b93955237
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Date deposited: 04 Jul 2022 20:13
Last modified: 04 Jul 2022 20:13
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Author:
Eberhard Schmid
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