| 摘要 |
PURPOSE:To make the current have such a waveform as to prevent instability due to acoustic resonance by specifying the percentage of the integrated absolute value of the higher harmonics power of the unstable frequency band contained in the whole electric discharge power. CONSTITUTION:A phenomenon, that unstable electric discharge does not occur practically in case that the power frequency components causing instability is less than the specified percentage of the whole electric discharge power even if the frequency components causing instability exist in the electric power because of the difference of discharge current waveform between its positive and negative cycles, is used. That is, lamps are lighted at a time of such a discharge current waveform that makes the percentage of the integrated value of the higher harmonics power causing instability in the whole discharge power less than about 36%. |
