V.Radha, Vigren (2016) Attenuation Of Electromagnetic Acoustic Noise From A Variable Speed Induction Motor By Using Dynamic Vibration Absorber. Masters thesis, Universiti Sains Malaysia.
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Abstract
Hingar akustik elektromagnetik mempunyai ciri ton hingar yang dihasilkan oleh motor induksi kelajuan boleh ubah mewujudkan suasana yang tidak selesa kepada pengendali mesin. Hingar yang berlaku pada frekuensi tinggi ini kebiasaannya berlakupada gandaan frekuensi pensuisan pada pembalik. Penyelesaian masalah hingar ini pada umumnya dicapai dengan rekabentuk elektromekanikal dan modulasi lebar denyut untuk membasmi harmonik yang menyebabkan hingar. Penggunaan penyerap getaran dinamik adalah antara alternatif yang dikaji di dalam penyelidikan ini. Ujian spektrum menunjukan bahawa daya tindakan elektromagnetik mempengaruhi secara langsung hingar elektromagnetik yang dihasilkan oleh motor induksi. Gandaan harmonik 3 kHz pada spektrum modulasi lebar denyut berlaku juga pada spektrum getaran permukaan dan spektrum hingar. Analisis mod dan ujian spektrum menunjukan bahawa hingar dengan frekuensi 6 kHz pada kelajuan 1250 rpm dan ke bawah adalah disebabkan oleh getaran paksa. Pada halaju di atas 1250 rpm, hingar 3 kHz adalah disebabkan resonans. Bolt M6 sepanjang 20 mm digunakan sebagai penyerap getaran dinamik dan dipasang pada permukaan motor untuk mengurangkan hingar pada 6 kHz. Penyerap getaran dinamik menyerap getaran sebanyak 20% hingga 86%pada permukaan motor dan pengurangan aras tekanan bunyi sebanyak 12 dB(A) dapat dicapai. Ia juga berkesan pada lokasi lain pada motor dan juga pada semua kelajuan operasi. Penyerap getaran dinamik telah terbukti untuk mengurangkan hingar elektromagnetik daripada motor induksi kelajuan boleh ubah. ________________________________________________________________________________________________________________________ Tonal electromagnetic acoustic noise radiated from variable speed induction motor can be annoying to human operator. Occurring at high frequency, it often occurs at multiples of the inverter switching frequency. Solutions for the noise attenuation have been generally by means of electromechanical design and pulse width modulation (PWM) strategy to remove harmonics leading to noise generation. Dynamic vibration absorber (DVA) as an alternative solution was implemented in this research. Spectral test revealed that the input electromagnetic excitation has direct influence on the radiated electromagnetic acoustic noise from the induction motor. The multiples of 3 kHz harmonics in PWM spectrum was also present in the surface vibration and sound pressure spectrum. From experimental modal analysis and spectral test, it was found that the 6 kHz acoustic noise was due to forced vibration for speed of 1250 rpm and below. While at above 1250 rpm, the 3 kHz noise was due to resonance. A 20mm M6 bolt was used as DVA and attached to a point on the motor housing for targeted noise attenuation at 6 kHz. The DVA was able to absorb the surface vibration in the range of 20 to 86% and maximum sound pressure level reduction of 12 dB (A) was achieved. It was also effective at other locations on motor as well as at different operating speed. The DVA was thus proven to be a feasible method for electromagnetic noise attenuation in induction motor.
| Item Type: | Thesis (Masters) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/user/submitPublicationAndFinishLater.action |
| Subjects: | T Technology T Technology > TJ Mechanical engineering and machinery > TJ1-1570 Mechanical engineering and machinery |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Mekanikal (School of Mechanical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 30 Aug 2018 08:17 |
| Last Modified: | 30 Aug 2018 08:17 |
| URI: | http://eprints.usm.my/id/eprint/41607 |
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