Method of operating a water-circulating household appliance

Abstract

Herein a method of operating a water-circulating household appliance 2 is disclosed. The water-circulating household appliance 2 comprises an electric motor 4 and a washing liquid circuit 6, the washing liquid circuit comprising a pump 8 for circulating washing liquid through the washing liquid circuit. A portion of the washing liquid circuit is arranged in thermal communication with the electric motor. For heating the washing liquid, the method comprises a step of driving the electric motor, over a time period longer than 1 minute, with a higher electrical power input than required for circulating the washing liquid through the washing liquid circuit with the pump rotating in the primary direction of rotation. Also disclosed is a water-circulating household appliance 2.

1 . A method of operating a water-circulating household appliance, the water-circulating household appliance comprising an electric motor and a washing liquid circuit, the washing liquid circuit comprising a pump for circulating washing liquid through the washing liquid circuit, a portion of the washing liquid circuit being arranged in thermal communication with the electric motor, wherein the electric motor has a first direction of rotation and a second direction of rotation and is arranged to drive the pump, and wherein the pump has a primary direction of rotation corresponding to the first direction of rotation of the electric motor, wherein the method comprises a step of driving the electric motor, over a time period longer than 1 minute, with a higher electrical power input than required for circulating the washing liquid through the washing liquid circuit with the pump rotating in the primary direction of rotation. 
     
     
         2 . The method according to  claim 1 , wherein the step of driving the electric motor comprises a step of rotating the electric motor in the second direction of rotation to rotate the pump in a direction opposite to the primary direction of rotation. 
     
     
         3 . The method according to  claim 1  wherein the step of driving the electric motor comprises a step of causing an excessive electrical loss in the electric motor exceeding a normal electrical loss in the electric motor associated with rotating the pump in the primary direction for circulating the washing liquid through the washing liquid circuit. 
     
     
         4 . The method according to  claim 3 , wherein the step of causing the excessive electrical loss comprises a step of repeatedly starting and stopping the rotation of the electric motor a number of times during each of a number of consecutive 1 minute time periods. 
     
     
         5 . The method according to  claim 3 , wherein the step of causing an excessive electrical loss comprises a step of sending a DC voltage into at least one set of windings of the electric motor. 
     
     
         6 . The method according to  claim 3 , wherein the step of causing the excessive electrical loss comprises a step of sending an out of phase AC voltage through at least one set of windings of the electric motor. 
     
     
         7 . The method according to  claim 1 , comprising a step of measuring a temperature of the washing liquid. 
     
     
         8 . The method according to  claim 1 , comprising a step of rotating the electric motor in the first direction of rotation and rotating the pump in the primary direction of rotation. 
     
     
         9 . A water-circulating household appliance comprising an electric motor and a washing liquid circuit, the washing liquid circuit comprising a pump driven by the electric motor and arranged to circulate washing liquid through the washing liquid circuit, a portion of the washing liquid circuit being arranged in thermal communication with the electric motor, wherein the water-circulating household appliance is arranged to perform the method according to  claim 1 .