| 摘要 |
PURPOSE:To prevent a regenerative brake system from entering into uncontrollable state by turning an auxiliary exciting transistor ON under a state where each contactor and a regenerative contactor are turned OFF and measuring a voltage to be applied on a chopper driving means at that time. CONSTITUTION:Upon turning a travel lever to a neutral position under halting state of vehicle, a drive contactor 3, a reverse contactor 4, a regenerative contactor 7 and a field weakening contactor 13 are held in OFF state. Subsequently, an auxiliary exciting transistor 9 is turned ON and a sensor 20 detects a voltage Vo to be applied on the transistor 9 under that state. When the field weakening contactor 13 is in short-circuited state due to fusion, for example, the applying voltage is considerably higher than 0 volt. Consequently, a controller 17 decides that the field weakening contactor 13 is short-circuited if the applying voltage Vo, detected through the sensor 20, is not 0 volt but higher than a predetermined level and then prohibits travel control thus maintaining the vehicle in halting state. |
