| 摘要 |
<p>PURPOSE:To control the rotational frequency of a drive motor for an operatorless vehicle when a regenerative current becomes higher than predetermined value by utilizing the current flowing through the motor when the vehicle runs at higher than predetermined speed on a descent. CONSTITUTION:When an operatorless vehicle runs down on a descent, a regenerative current will flow through a drive motor 1 thereof to cause the voltage applied to a polarity and voltage discriminator 4 to become negative. When the vehicle further continues to run down on the descent until the voltage becomes higher than predetermined velue, a discriminator 4 generates a signal, which is applied to an amplifier 5. The output from the amplifier 5 is applied through a relay 6 to a shunt field winding control switch lg to thereby cause the switch lg to be closed. Thus, the switch 1g shorts a shunt field winding resistor 1b to thereby increase the shunt field winding current of the winding 1e.</p> |
