To stop a motor driving when an AC power source stops or a voltage drops during a dehydrating operation or a dehydration braking, to surely stop a washing-cum-dehydrating tub by a simple and inexpensive constitution after the restoration of the AC power source, and to increase safety in a washing machine which drives the motor by an inverter circuit.
A DC power source is constituted by connecting a rectification circuit 3 with the AC power source 1, and the motor 6 is driven by inverting DC power into AC power by the inverter circuit 5. A voltage state of the AC power source 1 is detected by power source voltage-detecting means 4 and 15, and the inverter circuit 5 is controlled by a controlling means 10. The controlling means 10 stops the driving of the motor 6 when the power source voltage- detecting means 4 and 15 detect the voltage decrease or the voltage stop of the AC power source 1 when the motor 6 is driven. Then, the rotation of the motor 6 is stopped by short-circuit braking when the returning to the normal voltage state of the AC power source 1 is detected.
SAKIDA YOSHIAKI
KUBO YOSHIO
MATSUI SHOICHI