Patent ID: 11905637
Assignee: LG ELECTRONICS INC.
Field: Other consumer goods (Other fields)
Classification: CPC D  H  Y | IPC D  H

Claim 3:
4. A laundry treatment machine comprising:
a washing tub;
a washing tub motor to rotate the washing tub;
a drain pump including a water introduction part into which wash water in the washing tub is introduced, a vortex chamber formed within the water introduction part, and an impeller disposed in the vortex chamber;
a drain motor operating the impeller;
a converter to output a direct current (DC) voltage;
an inverter to convert the DC voltage from the converter into an alternating current (AC) voltage based on a switching operation and to output the converted AC voltage to the drain motor;
an output current detector to detect an output current flowing in the drain motor; and
a controller to control the drain motor to rotate at a first speed if the wash water introduced to the vortex chamber is fully filled and a water level in the washing tub is kept constant, and to rotate at a second speed lower than the first speed if the wash water introduced to the vortex chamber is partially filled, and then increase the speed of the drain motor after a predetermined time,
wherein the controller controls to supply the same power to the drain motor, when the drain motor is driven at the first speed and when the drain motor is driven at the second speed,
wherein, while the water level in the washing tub decreases, the controller controls the speed of the drain motor to be gradually increased from a third speed lower than the first speed and higher than the second speed,
wherein the output current is substantially constant in a period during which the speed of the drain motor gradually increases from the third speed.