A washing machine including a drainage pump to discharge water from a tub of the washing machine through a drainage passage, a first filter to which the water flows due to the drainage pump and provided along the drainage passage to filter out foreign matter equal to or greater than predetermined size, and a second filter to which the water flows from the first filter and provided along the drainage passage and to filter out foreign matter smaller than the predetermined size, wherein the drainage passage includes a first connecting hose to guide the water to flow from the tub to the first filter, a second connecting hose to guide the water to flow from the first filter to the second filter, and a drainage hose to guide the water to be discharged from the second filter to the outside of the washing machine.

A washing machine including a drainage pump to discharge water from a tub of the washing machine through a drainage passage, a first filter to which the water flows due to the drainage pump and provided along the drainage passage to filter out foreign matter equal to or greater than predetermined size, and a second filter to which the water flows from the first filter and provided along the drainage passage and to filter out foreign matter smaller than the predetermined size, wherein the drainage passage includes a first connecting hose to guide the water to flow from the tub to the first filter, a second connecting hose to guide the water to flow from the first filter to the second filter, and a drainage hose to guide the water to be discharged from the second filter to the outside of the washing machine.

According to the present invention, a control method for a clothing treatment device comprises the steps of: transmitting a power-related order to a motor that provides electric power to a drain pump in order to perform a dehydration process; detecting a unit revolution count of the motor while the dehydration process is performed; determining whether the detected unit revolution count exceeds a preset limited revolution count; reducing the unit revolution count of the motor to a predetermined unit revolution count if the detected unit revolution count exceeds the limited revolution count; and repeatedly transmitting the power-related order to the motor.

According to the present invention, a control method for a clothing treatment device comprises the steps of: transmitting a power-related order to a motor that provides electric power to a drain pump in order to perform a dehydration process; detecting a unit revolution count of the motor while the dehydration process is performed; determining whether the detected unit revolution count exceeds a preset limited revolution count; reducing the unit revolution count of the motor to a predetermined unit revolution count if the detected unit revolution count exceeds the limited revolution count; and repeatedly transmitting the power-related order to the motor.

A washing machine appliance includes a sump for collecting wash fluid, a supply valve for supplying the wash fluid, a drain assembly for discharging the wash fluid from the sump, and a water level detection system for measuring sump pressures/fill levels. A controller is configured to perform an initial fill cycle and determine a first volume of wash fluid required to reach a target pressure. The drain assembly then drains the sump and the process is repeated to determine a second volume of wash fluid required to reach the target pressure. The difference between the first volume and the second volume is at least partially a result of wash fluid that the drain assembly could not discharge through the drain hose. The controller may determine that the external drain is elevated, and compensate accordingly, if a difference between the first volume and the second volume exceeds a predetermined threshold.

A washing machine appliance includes a sump for collecting wash fluid, a supply valve for supplying the wash fluid, a drain assembly for discharging the wash fluid from the sump, and a water level detection system for measuring sump pressures/fill levels. A controller is configured to perform an initial fill cycle and determine a first volume of wash fluid required to reach a target pressure. The drain assembly then drains the sump and the process is repeated to determine a second volume of wash fluid required to reach the target pressure. The difference between the first volume and the second volume is at least partially a result of wash fluid that the drain assembly could not discharge through the drain hose. The controller may determine that the external drain is elevated, and compensate accordingly, if a difference between the first volume and the second volume exceeds a predetermined threshold.

A washing machine appliance includes a sump for collecting wash fluid, a drain pump for discharging the wash fluid from the sump, and a water level detection system fluidly coupled to the sump. A controller is configured for monitoring the electric current drawn by the drain pump during a drain cycle and determining that the sump is empty based on a drop in the electric current. The controller then measures the sump pressure and determines that a fault condition exists with the water level detection system when the sump is empty and the sump pressure exceeds a predetermined pressure threshold, e.g., zero pressure corresponding to an empty sump.

The present disclosure relates to a drain pump driving apparatus and a laundry treatment machine including the same. A drain pump driving apparatus according to an embodiment of the present disclosure and a laundry treatment machine including the same include: an inverter to convert an input direct current (DC) voltage into an alternating current (AC) voltage by a switching operation and to output the converted AC voltage to a 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 in a first direction during a first period, rotate in a second direction opposite to the first direction during a second period, and continuously rotate in the first direction when a level of the output current at rotation in the first direction is greater than a level of the output current at rotation in the second direction. Accordingly, it is possible to secure a pumping performance of the drain pump.

The present disclosure relates to a laundry treatment machine. A pump motor provided in a drain pump is controlled to correspond to the operation of the main motor and the water level, so that the pump motor slows down based on the speed of rotation of the main motor and the water level and keeps operating at low speed. Therefore, the pump motor is able to keep operating without stopping operation, and the amount of noise caused by the start-up of the motor is reduced, and the time taken to align the rotor of the motor in position is reduced, thereby reducing drainage time and improving the drainage performance of the drain pump.

The present disclosure relates to a laundry treatment machine. A pump motor provided in a drain pump is controlled to correspond to the operation of the main motor and the water level, so that the pump motor slows down based on the speed of rotation of the main motor and the water level and keeps operating at low speed. Therefore, the pump motor is able to keep operating without stopping operation, and the amount of noise caused by the start-up of the motor is reduced, and the time taken to align the rotor of the motor in position is reduced, thereby reducing drainage time and improving the drainage performance of the drain pump.