| 摘要 |
PURPOSE:To switch a power supply system smoothly even upon occurrence of abnormality by a method wherein the title device is provided with a voltage detector and a switching controller, outputting a tap switching command for a reactor in accordance with a voltage level immediately before occurrence of the abnormality. CONSTITUTION:When an input switch 4 is closed, the electric power of a system is supplied to a variable voltage variable frequency power supply device (VVVF) 10 through an input transformer 6. When a signal for controlling the number of rotation of an AC motor 9 (ACC) is given from a driving signal setter 11 to the VVVF 10, a voltage, having a frequency matching with the ACC signal, is inputted into the AC motor 9 through an output transformer 7 and an output switch 5. VVVF control operation is effected under this condition. When an abnormality is generated in the VVVF 10 and a trouble, not permitting the continuation of the operation, has generated, a switching controller 13 switches a power supply into the other power supply system through a reactor 3 for restricting current so that the number of rotation of the AC motor 9 does not increase suddenly. |
