| 摘要 |
PURPOSE:To prevent the temperature rise of a hoisting-up motor in the hoisting- down operation and reduce the inverter capacity by setting the relation between the output voltage and the inverter output cycle in the hoisting-down operation so that the value of the output voltage lowers than that in the hoisting-up operation. CONSTITUTION:When winding-down operation starts at the time t1, an inverter starts the increase of cycle with a previously set inclination from a cycle 0hz with a voltage V0D to a cycle f2 with a voltage V2D set by a low speed setting device. If a cycle f1 with a voltage V1D is generated at the time t2, the inverter starts output for a hoisting motor, and the hoisting motor is released, and then starts revolution in the winding-down revolution, and speed is increased. If a cycle f2 with a voltage V2D is realized at the time t3, the inverter suspends the increase of cycle, and the hoisting-up motor is revolved at a constant low speed. At the time t4, the inverter starts the increase of cycle with a get inclination up to a cycle f3 with a voltage V3 set by a high speed setting device, and the hoisting-up motor increases speed again. |
