| 摘要 |
PURPOSE:To detect overload reliably by providing means for detecting excessive output current and insufficient rotational speed of a drive motor for a motor vehicle and detecting overload of the motor based on the logical product of outputs tram both detecting means and then producing an alarm. CONSTITUTION:Current of a motor (not shown) for driving a motor vehicle is determined from a voltage Vs across a shunt resistor 25 and thus determined current is fed to an overcurrent detecting means 1. An open collector type comparator IC compares the voltage VS with a reference voltage Vi set by a variable resistor VR1 and produces an output H when Vs>Vi. An open collector type comparator IC2 in a speed drop detecting means 2 compares a reference value Vf set by a variable resistor VR2 with a voltage Vo obtained by subjecting the output from a rotation sensor 19 to F/V conversion 22 and produces an output H when Vo<Vf. When both comparators IC1, IC2 produce outputs H, a logical product means 3 produces an output H and actuates an alarm generating means 4. According to the constitution, overload is detected reliably in case of continuous steep hill or at the time of motor lock. |
