Patent ID: 7506392

Claim:
A method of setting an extraction rotation speed for a drum in a laundry machine based on load imbalance detection, comprising: rotating, by a motor controlled by a drive controller of the laundry machine, the drum with a laundry load therein at an imbalance detection speed; detecting, by the drive controller, a variation amplitude of a phase angle between voltage and current applied to the motor; characterizing, by the drive controller based on the detected phase angle variation amplitude, a detected load imbalance in the drum as being in one of a plurality of pre-defined load imbalance zones, each zone corresponding to a range of said amplitude; transmitting, by the drive controller to a machine controller of the laundry machine, an imbalance indication signal to indicate the imbalance zone in which the detected load imbalance falls; selecting, by the machine controller based on the imbalance indication signal, an extraction rotation speed for the drum for an extraction operation; and sending, by the machine controller, a control signal to the drive controller indicating the selected extraction rotation speed for the drum for the extraction operation, wherein the selected extraction rotation speed is the lesser of a speed associated with the indicated imbalance zone and a maximum speed for the type of laundry load.