| 摘要 |
PURPOSE:To stabilize operation at light load by a method wherein the output voltage in an inverter is reduced at light load and the slip of an induction motor is increased to shorten an ON lag period. CONSTITUTION:A function generator 19 generating a predetermined signal in accordance with the output in a rectifier 7, namely the magnitude of the curent flowing into an induction motor 5 through a thyristor converter 2, and an inverter 4 is provided and the output in the function generator 19 is reduced by the predetermined value of the inverter 4 output voltage, namely the output in a function generator 11. The output voltage in the inverter 4 is reduced at light load to increase the slip of the induction motor 5 and an ON lag period is shortened. In this way, the output frequency in the inverter is increased and the inverter can stably be operated. |
