PSC motor improvement for direct drive clothes washer applications

Top load, vertical axis domestic washing machines using direct drive rapid reversing motors and simple speed reducers are becoming increasingly common in today´s world market. Theoretical and practical advantages of these systems include a significant reduction in cost and hardware complexity. Additionally, performance flexibility in agitation and spin activity is increased. Cost effectiveness of this approach is contingent upon applying standard induction motors and avoiding variable voltage, variable frequency or DC power supply driven motors. Contemporary products achieve cost effectiveness by confining permanent split capacitor (PSC) direct drive application to smaller washing machine basket sizes and lighter clothes loads. In this class of washing machine, agitator size, stroke-rates and general energy transfer is quite different from typical American washing machines. This paper presents the study and development of an upgraded PSC prime mover for direct drive application to large load capacity washers. Modified rotor resistance motors similar in size, weight and cost to the lighter PSC systems have been developed for 14 to 18 pound American (high energy agitation) machines. The motor operates in synergy with a simple duty cycle modulation electronic control. The theory of development with supporting dynamometer and washing machine data is submitted in this text