| 摘要 |
PURPOSE:To prevent a vibrator from impossibility of conveying by arranging a saturation detector for detecting saturation or unsaturation of output voltage and a frequency dropping circuit for dropping driving frequency in a power converting device at the time of generating a saturating judging output in the saturation detector. CONSTITUTION:The vibrator 1 is driven with the prescribed frequency near the resonance frequency thereof as loading and controlled so that vibration amplitude comes to the prescribed value. Then, in the frequency dropping circuit, at the time of generating the saturation judging output in the saturation detector 13 for detecting the saturation or the unsaturation of the output voltage, the driving frequency in the power converting device is dripped. In this frequency dropping circuit, during generating the saturation judging output in the saturation detector 13, a circuit 14 integrating the positive fixed level signal and a circuit 16 subtracting value being in proportion to positive output in the circuit 14 from the prescribed frequency are provided, and the circuit 14 is made so as to input a negative fixed level signal during generating the unsaturation judging output in the saturation detector 13. In this result, when the resonance frequency is drastically dropped by rapidly increasing the load in the vibrator, the impossibility of conveying in the vibrator is prevented. |
