SINGLE RELAY FOR MOTOR AND HEATER CONTROL

ABSTRACT A microprocessor controlled fabric drying apparatus is provided including structure having a rotatable fabric tumbler, a drive motor for driving the tumbler, and a heater for drying fabrics in the tumbler. A first circuit energizes the drive motor and includes a first relay switch and a centrifugal switch. The first circuit is operable for initiating energization of the drive motor in a first posture of the centrifugal switch and for main-taining rotation of the drive motor in a second posture thereof. A second circuit energizes the heater and includes a second relay switch, An interfacing circuit electrically interfaces the micro-processor with the drive motor and the heater through a single relay coil for operating the relay switches under control of the micro-processor. The first circuit includes a portion for maintaining energization of the drive motor during periods of deenergization of the heater and the microprocessor controls the heater without interrupting operation of the drive motor.