| 摘要 |
PURPOSE:To protect an induction motor, being driven through an inverter set with a V/F pattern, against overvoltage. CONSTITUTION:The overvoltage preventing unit comprises a reactive power detector 11 disposed between the output side of an inverter 50 and an induction motor 51, a voltage regulator 12 disposed between the output side of the inverter 50 and the reactive power detector 11, switches 13, 14 for conducting or short- circuiting the voltage regulator 12, and a reactive power control section 15. The reactive power control section 15 detects a start finish signal of the induction motor provided from the inverter 50 and compares a preset reactive power vague with a reactive power value detected through the reactive power detector 11 and then regulates the voltage of the voltage regulator 12 based on the comparison results. |
