Abstract: An energy saving method of operating a washing machine such that the amount of water added to the washer basket is proportionate to the weight of the articles to be washed includes the steps of determining a normalized inertia of the washer basket loaded with articles to be cleaned; determining an estimated weight of the load of articles to be washed based upon the normalized inertia value; and controlling a washer water supply system to add a load-specific volume of water to the washer basket, the magnitude of the load-specific volume of water corresponding to the estimated weight of the articles to be washed. An energy efficient washing machine in accordance with this invention includes an induction motor coupled to the washer basket, a washer water supply system coupled to the washer basket, and a washer controller coupled to the drive motor and the washer water supply system so as to respectively control operation thereof.

Abstract: A control includes a shaft rotatable between a plurality of positions. The base of a spring is fixed relative to the shaft and arms extend from the base parallel to the shaft. Each arm includes a resilient finger and a nose projects from each finger toward the shaft. The noses are 180 angular degrees apart and at different positions longitudinally of the shaft. A cam rotates with the shaft and the noses are biased against the outer surface of the cam. A plurality of recesses are angularly spaced apart around the outer surface of the cam in pairs which are spaced 180 angular degrees apart. One of each pair of recesses is longitudinally aligned with one nose and the other of that pair is longitudinally aligned with the other nose. The noses and recesses provide a detent when the recesses of a pair are angularly aligned with the noses with which they are longitudinally aligned and do not form a detent when the shaft is substantially 180 angular degrees removed therefrom.

Abstract: A power switching arrangement for a self-cleaning oven appliance incorporating a unique arrangement of two double throw relays in the oven power control circuit. The two relays are operatively interconnected to selectively couple the oven bake and broil elements to the three wire power supply to switch the bake element across L1 and L2 and the broil element across L1 and N when operating in the bake mode, and switch the bake element out of the circuit and the broil element across L1 and L2, when operating in the broil mode. The interconnection is accomplished in a manner which prevents both heating elements from being simultaneously energized at full power regardless of the failure mode of the switching circuitry, thereby eliminating the need for a thermal limit switch to guard against excessive temperatures in the oven resulting from worst case switching circuit failures.

Abstract: An improved temperature sensor failure detection arrangement for a temperature controlled heating device of the type having a heater, an electronic controller for controlling the power level applied to the heater, and a temperature sensor. The controller includes an internal heater energy counter, which is incremented and decremented at rates determined as a function of the power level applied to the heater such that the count of the heater energy counter approximately tracks the temperature of the heater. The controller periodically compares temperature information from the temperature sensor with the count of the heater energy counter to check for abnormal operating condition of the temperature sensor.

Abstract: A control circuit is disclosed for appliances such as dishwashers and clothes washers employing a microprocessor programmed to respond to user selected options to determine the operating sequence of the appliance. The control circuit includes a manually operable switch which when actuated generates a reset signal which interrupts or cancels appliance operation by resetting the microprocessor and additionally generates an initiating signal which when detected by the microprocessor following reset, causes the microprocessor to initiate a drain cycle to remove any water present in the appliance as part of the reset program routine.

Abstract: A ground fault interrupter type device for protecting an electrical load device such as a range which has conductors supplied from a power source including overcurrent interruption means for interrupting the power source when a predetermined current threshold is exceeded. The electrical load device is subject to a first class of failure characterized by excessive current flow between at least one of the conductors and a ground reference point, with circuit current remaining at or below the predetermined current threshold; and to a second class of failure characterized by current through at least one of the conductors being above the predetermined current threshold. Failures of the second class include ground fault failures. In order to reduce the current interruption capability requirement for the ground fault interrupter device, there is included a means for preventing conductor interruption thereby in the event a failure of the second class occurs.

Abstract: A reset generator circuit including a power monitor subcircuit which provides first and second logic level signals which specify the power supply as being above or below a preselected threshold level. A logic circuit comprising a series of interconnected NAND gates responds to the output signals generated by the power monitor subcircuit and to a signal from a capacitor charge monitor circuit. The capacitor charge monitor circuit develops logic signals which reflect the magnitude of the voltage across a capacitor which is part of a timing circuit. The control signal output from the logic circuit drives one input to a reset control gate and also controls the charge on the capacitor. The other input to the reset gate is also driven by the charge monitor circuit. The reset gate operates a switching element which provides the proper reset signal adapted for coupling to a microprocessor.

Abstract: A piezoelectric transducer frequency self-calibration system interrogates the transducer by driving it with various frequencies within a specified range while monitoring the transducer output power level. Two threshold frequency points are identified at which the output power level is at a predetermined threshold level less than the expected maximum output level, and the average of these two threshold frequencies is taken to be the optimum frequency.

Abstract: A food temperature-sensing probe assembly for monitoring the internal temperature of food while it is being cooked in a microwave oven includes a disc-like reflector either slidably or fixedly mounted on the probe housing adjacent to, but spaced from, the food. The reflector serves to prevent overcooking of the food in a region immediately adjacent the probe.

Abstract: Food temperature responsive apparatus for controlling an oven. The apparatus includes a temperature sensing thermistor which may be included in a probe adapted for insertion into food being cooked in an oven. The apparatus includes simplified and effective means, in the form of voltage dividers and comparators, for performing the functions of de-energizing the oven heating means and energizing an audible alarm when interior food temperature reaches a preset temperature, protecting against an open-circuited or a short-circuited condition in a sensing circuit which includes the thermistor, guarding against responding to transient electrical noise, and latching the oven heating means in a de-energized condition once it has been de-energized. Even though the thermistor has a non-linear resistance versus temperature characteristic, the apparatus provides a linear temperature presetting scale and includes a linear temperature presetting potentiometer.

Abstract: A food temperature-sensing probe assembly for monitoring the internal temperature of food while it is being cooked in a microwave oven includes a disc-like reflector mounted at a fixed position on the probe housing a predetermined distance from the tip of the probe housing. The probe housing is adapted to be driven into the food so that the reflector is adjacent to, but spaced from, the food. The reflector serves to prevent overcooking of the food in a region immediately adjacent the probe. An indicator on the probe housing shows the minimum recommended insertion depth of the probe into the food, and therefore the maximum reflector-to-food spacing, for effective shielding. The reflector and the handle may be formed as a single assembly held together by insert molding.

Abstract: A food temperature-sensing probe assembly for monitoring the internal temperature of food while it is being cooked in a microwave oven includes a disc-like reflector mounted on the probe housing at a predetermined distance from the tip of the probe housing. The probe housing is adapted to be driven into the food so that the reflector is adjacent to the food. The reflector serves to prevent overcooking of the food in a region immediately adjacent the probe. A spacer is mounted adjacent the reflector and extends toward the tip of the probe housing to space the reflector away from the food at least a predetermined minimum distance.

Abstract: A disc-like reflector, in addition to preventing excessive cooking of the food in a region immediately adjacent the probe housing, functions as a spring to hold the handle and reflector assembly together. The assembly remains tightly together despite different coefficients of thermal expansion of the various component parts.