| 摘要 |
PURPOSE:To prevent overheat in a DC electric car, by judging an occurrence of a failure when a voltage adjusting means delivers a current intermittent operation signal although the voltage across a capacitor is lower than a predeter mined value, so as to stop regenerative operation. CONSTITUTION:During regenerative operation of an electric car, when the voltage Vc of a capacitor is raised from a set value set on a setting unit 36 due to regenerative current from a feeder line 4, a voltage adjuster 34 delivers a signal to a phase shifter 35 to intermittently turn on a chopper 33 in order to allow a load resistor 32 to consume power. In this stage, when the voltage adjuster 34 continue to transmit an intermittent signal from the chopper 33 to the phase shifter 35 although the input voltage Vc is lower than a set value set on a low voltage setting unit 50, an abnormality detecting circuit 40 judges that the voltage adjuster 34 fails, and stops the operation of the chopper 33 through the phase shift 34 so as to prevent the load resistor 32 from being burnt. Thus, there is no risk of useless power consumption, and further it is possible to avoid the overheat and burning of a resistor, and as well to a risk of fire. |
