| 摘要 |
PURPOSE:To prevent an overcurrent from flowing through the motors by a method wherein an auxiliary switches are provided which are interlocked with main switches provided between the motors and a variable boltages variable frequencies inverter and feeding a pattern signal which decreases currents of the motors. CONSTITUTION:When the motors 4, 5 are normally operated and the main switches 9, 10 are closed, the auxiliary switches 15, 16 are closed as well. Assuming now that the main switches 9 is opened so as to release the motor 4, the auxiliary switch 15 is opened interlockingly with the main switch 9, and short-circuits at both ends of a voltage dividing resistor 12 are released. As a result, a pattern voltage of a patterns signal generator 11 is fed to a current control operational circuit 17 at a value of the voltage divided by the voltage dividing resistors 12, 14, and a current component of a control signal fed from the operational control circuit 20 to VVVF inverter 3 decreases according to the release degree of the motor 4. Therefore, there is no possiblity of the overcurrent flowing in the motor 5. |
