Patent ID: 7331075

Claim:
A spin-dry control method in a washing machine, comprising: sensing a first clothes amount contained in a washing tub; sensing an unbalance of the clothes and a second clothes amount, after execution of the sensing of the first clothes amount; determining a final clothes amount, based on the first clothes amount and the second clothes amount; and executing a main spin-dry process, based on the final clothes amount, wherein the sensing the unbalance of the clothes and the second clothes amount comprises: accelerating a motor, which is adapted to rotate the washing tub, after a start-up thereof such that an RPM of the motor reaches a predetermined RPM; constantly rotating the motor in a constant speed state for a predetermined time when the RPM of the motor has reached the predetermined RPM; measuring a pulse width modulation (PWM) duty value of the motor at the accelerating and the constantly rotating; measuring an RPM ripple of the motor at the constantly rotating; determining an unbalance index based on the RPM ripple; and determining the second clothes amount based on the PWM duty value and the unbalance index.