Natural frequencies of stators of small electric machines

Ellison, A.J.; Yang, S.J.

doi:10.1049/piee.1971.0029

Cited by 48 publications

(10 citation statements)

References 2 publications

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“…The basic methods of calculating the natural mode frequencies (f m ) can be found in [10], [12], and [15][16][17]. First, the stator is considered as a freely vibrating ring; then stator teeth and winding masses are considered.…”

Section: Calculation Of Natural Mode Frequencymentioning

confidence: 99%

“…Cogging torque, torque ripple and magnetic radial forces are the main electromagnetic sources of noise and vibration. According to several researchers, the reduction of cogging torque and torque ripple can significantly reduce the vibration and acoustic noise [1][2][3][4][5][6][7][15][16][17]. These research works did not establish the fundamental relationship between torque ripple or cogging torque with noise and vibration.…”

Section: Introductionmentioning

confidence: 99%

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Analytical model for predicting noise and vibration in permanent magnet synchronous motors

Islam

Husain

2009

2009 IEEE Energy Conversion Congress and Exposition

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This paper analyzes the noise and vibration in permanent magnet synchronous motors (PMSM). Electromagnetic forces have been identified as the main cause of noise and vibration in these machines rather than the torque ripple and cogging torque. A procedure for calculating the magnetic forces on the stator teeth based on the 2D finite element (FE) method is presented first. An analytical model is then developed to predict the radial displacement along the stator teeth. The displacement calculations from analytical model are validated with structural FEA and experimental data. Finally, the radial displacement is converted into sound power level. Four different PMSM topologies suitable for electric power steering application are compared for their performances with regards to noise and vibration.

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Section: Calculation Of Natural Mode Frequencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analytical model for predicting noise and vibration in permanent magnet synchronous motors

Islam

Husain

2009

2009 IEEE Energy Conversion Congress and Exposition

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“…The vibration and resulting acoustic noise is particularly severe when stator resonance occurs, i.e., when the frequencies and waveforms of the excitation (usually radial magnetic forces) coincide with the normal mode shapes and natural frequencies [1], [3], [13]. It is important to accurately predict the resonant frequencies and vibration characteristics of the SRM stator in order to design quiet electrical machines [10], [11] and for quiet operation [3].…”

Section: Introductionmentioning

confidence: 99%

“…The contribution of the stator poles and ribs has been investigated with numerical computations in previous papers [4], [13], [14]. Generally, the poles and ribs of the SRM stator cannot be treated as an extra mass (an acceptable effect in induction motors) [4], [11], [12] although the analytical formulas using the assumption of "extra mass" showed a good estimation of the frequencies of the low order modes. Many mode shapes are hidden under the "extra mass" assumption and the poles and ribs play a "stiffness" role on the resonant frequencies of high-order modes [4], [13], [14].…”

Section: Introductionmentioning

confidence: 99%

Impact of stator windings and end-bells on resonant frequencies and mode shapes of switched reluctance motors

Cai¹,

Pillay

Tang

2002

IEEE Trans. on Ind. Applicat.

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One of the main drawbacks of switched reluctance motors (SRMs) is vibration and acoustic noise, which limits their application. An accurate predication of the modal vibration frequencies of the SRM stator is essential in order to design a lowvibration motor and operate it quietly. Electronic techniques for noise reduction also depend on knowledge of the resonant frequencies, which depend on the mechanical structure surrounding the laminations. This paper examines the effects of the stator windings and end-bells on stator modal vibration frequencies. The error in the calculation of the resonant frequencies can be up to 20% if the influence of end-bells is neglected. The numerical computations of the stator mode shapes and resonant frequencies are validated with experimental results.

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“…As most stators of motors are of the double-shell type, consisting of an outer frame and an inner stator core, Erdelyi [18] considered a model of two thin shells joined by key bars, but the results were close to the measured data only when the ratio of the radial thickness of the core to the mean radius of the core was less than 0)2. To improve this model, Ellison and Yang [19] calculated the natural frequencies of a stator consisting of a thin frame and a thick laminated core loaded with teeth and windings, solidly coupled by key bars. However, none of these methods has been proved to be e!ective for real motor structures.…”

Section: Introductionmentioning

confidence: 99%