Patent ID: 8441248
Filing Date: 2013-05-14
Classification: D06F

Abstract:
1. A method of determining a phase relationship between AC mains (L1 and L2) supplying electricity to an electric motor and electric heating element in a clothes dryer comprising a drying chamber, rotated by the electric motor, an air system supplying and exhausting air from the treating chamber, with the supply air heated by the electric heating element, and a controller coupled to and controlling the operation of the electric motor and electric heating element to implement a cycle of operation, the method comprising: generating a zero-crossing timing signal from zero crossings of the L1 signal received by the controller; determining a peak time corresponding to a peak in the amplitude of the L2 signal applied to the electric heating element; determining a time differential between the peak time and a zero crossing from the zero-crossing timing signal; and determining the phase relationship by matching the time differential to at least one time window indicative of an anticipated phase relationship.