| 摘要 |
PURPOSE:To make stable control achievable without receiving any effect of high-frequency noise due to an inverter by making a switch in circuit at time of power failure and feeding an inverter circuit and a control circuit with electric power from a direct voltage source. CONSTITUTION:AC power of a power source 1 is converted into a direct current by a rectifier circuit 2, and further it is smoothened by a smoothing capacitor 4, inputted into an inverter switching circuit 5, and an induction motor 7 is driven via a motor circuit 6, thus operation takes place at the specified speed. In addition, the power source 1 comes to a dc power source 10 for a dc control circuit by a rectifier circuit 9, through which a signal control circuit 11 operates, inputting a signal from an external switch circuit 12 or outputting it to an external output circuit 13 of a brake or the like. When the power source 1 is normal, an operating switch 18 at time of power failure is being opened, keeping off any noise to the control circuit. At time of the power failure, this switch 18 is closed, thereby driving the induction motor 7. With this constitution, operation can be done without receiving any effect of high frequency noise and, what is more, operation to the nearest floor can be done at the power failure. |
