| 摘要 |
PURPOSE:To prevent over speed at the switching by eliminating the period during which the brake torque of two motors become zero simultaneously, with a time lag provided in the switching of the motors from the regenerative brake range to the generation brake range. CONSTITUTION:While contacts 3/4 and 5/6 of a controller 14 are on, excitation coils 101 and 31 are at an on state and motors 2 and 4 are in the regenerative brake range. Under such a condition, a controller 14 is operated to turn a contact 1/2 on. This cuts the excitation coil instantaneously and a voltage relay 16 turns on conferming the annihilation of the power source of the main circuit causing an excitation coil 91 to be closed whereby a motor 2 moves into the generation brake range. With the excitation coil 91 on, an excitation coil 151 turns on and a time limiting relay 15 switches off a self-hold circuit of the excitation coil 31 in a fixed time interval to cut the coil 31. With a contactor 3 on, a voltage relay 17 switches on a contact confirming the annihilation of the main circuit causing an excitation coil 100 to be closed whereby the motor 4 moves to the generation brake range. |
