Abstract: Provided is a washing machine and a method of controlling the same, the washing machine including: a tub provided to accommodate water therein; a rotating tub rotatably installed inside the tub; a ball balancer provided in the rotating tub; a washing motor configured to rotate the rotating tub; a drain motor configured to drain water from the tub; and a controller configured to; based on completing a washing cycle or a rinsing cycle, drive the drain motor; based on a water level in the tub reaching a first water level threshold, drive the washing motor for a first period of time; and based on the first period of time elapsing, stop the washing motor and the drain motor.

Abstract: A washing machine for controlling optimal operating revolutions per minute (rpm) of a drain pump in a draining course and a dehydrating course includes a washing tub; a drain pump configured to drain water in the washing tub; a pump motor configured to operate the drain pump; an inverter circuit configured to supply a driving current to the pump motor to operate the drain pump; and a controller configured to control the inverter circuit to supply reference power to the pump motor in response to starting a draining course, determine reference revolutions per minute (rpm) based on average rpm of the pump motor during a preset period of time, and control the inverter circuit to operate the pump motor at the reference rpm in response to the determining of the reference rpm.