| 摘要 |
PURPOSE:To suppress the overvoltage of a transistor chopper with low loss by connecting in series a condenser and a diode connected in parallel with the transistor and detecting the voltage of the condenser, thereby controlling the transistor for ON or OFF states. CONSTITUTION:A series circuit of a diode 44 and a condenser 46 and an overvoltage suppressing circuit 22 which has a resistor 40 provided at the diode 44 and a transistor 42 are provided in a circuit in which an armature chopper 12 and armature circuits 14, 16, 18 are connected to a DC power source 10. Field circuits 30, 32, 34 and other controlled power source 36 are connected as loads across the condenser 46, and the voltage of the condenser 46 are detected by a detector 48, thereby controlling ON or OFF the transistor 42. Accordingly, excessive energy stored in the condenser 46 can be fed back to the power source 10, thereby largely reducing the power consumption and efficiently suppressing the overvoltage. |
