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HAIT Journal of Science and Engineering B Volume 2, Issues 5-6, pp. 821-829 © 2005 Holon Academic Institute of Technology | ||||
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Detection of acoustic resonance in metal halide lamps
Yao C. Hsieh1,*, Ming J. Soong2, Hsien W. Chen3,
and Chin S. Moo3
1Department of Electrical Engineering, Kao-yuan Institute of Technology, | Kaohsiung County 821, Taiwan, R.O.C. 2Energy & Resources Laboratories, Industrial Technology Research Institute, Hsinchu County 310, Taiwan, R.O.C. 3Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, R.O.C. *Corresponding author: ychsieh@cc.kyit.edu.tw Received 1 March 2005, accepted 6 June 2005
| Investigation of the acoustic resonance in metal halide lamps is essential for engineers designing a high-frequency electronic ballast. This paper proposes a simple method of detecting the acoustic instability by measuring the lamp voltage. The standard deviation in the lamp voltage is used as an index to determine the occurence of acoustic resonance. With this index, the degree of the lamp arc instability can easily be specified. Experiments are carried out on various 70W lamps to inspect the influence of the lamp type, the used hours, and the operating power on the frequency spectra of acoustic resonance.
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