Washing machine
A washing machine comprises an outer drum and an inner tub having water-expelling holes on its side wall. On the bottom of the inner tub, an agitator rotated intermittently by a motor is supported by means of bearings. An air trap is provided in communication with the gap between the outer and inner tubs. When the washing operation is started, the agitator is rotated and due to the pumping action of the agitator, the water level between the inner and outer tubs falls temporarily, which is detected by the pressure sensor connected to the air trap. The motor is deenergized according to the output from the pressure sensor and the agitator is stopped. Then the water level starts rising temporarily again thus the pressure sensor output is increased, which in turn energizes the motor and rotates the agitator. When such ON and OFF of the motor are repeated for more than the predetermined number of times, the washing operation will be completed. During the water-expelling process, the time required to obtain substantially constant changing rate of the pressure sensor output from the start of the water-expelling is measured. The energizing time and the braking timing of the motor for rotating the inner tub are controlled by the multiple of the measured time.