| 摘要 |
PURPOSE:To enhance safety by providing a control means for transmitting a control signal upon occurrence of an abnormal state, controlling the output frequency of an inverter means according to the control signal, and stopping a motor while braking. CONSTITUTION:A control means 5 comprises a microcomputer 6 for controlling an inverter and gradually accelerate an inverter means 3 up to a predetermined frequency through a power Tr drive circuit 7 in response to the function of an operating switch 9 and then drives the inverter means 3 at a predetermined frequency thus driving a motor 4 at a desired r.p.m. Upon occurrence of an abnormal state, the selection switch of the microcomputer is turned to brake side and a brake signal is transmitted. Output frequency of the inverter means 3 is then lowered gradually so that the r.p.m. being set by the inverter means 3 will be lower than the r.p.m. of the motor 4 due to the inertia of load thus lowering the r.p.m. of the motor 4. Since the motor can be stopped quicker than the stoppage of free run due to the inertia of load, the safety is enhanced. |
