Abstract: A power supply circuit detects ground fault paths, and miswiring of the load, using a test mode in which electrical power is applied to only one power output terminal of the power supply relative to the ground terminal, while substantially no electrical power is applied to the second power output terminal relative to the ground terminal. If application of power during the test mode causes substantial current flow through ground, then there is a ground fault path, or an incorrect connection between the midpoint of the load and ground. The power supply further includes unique features for signaling the presence and kind of fault it has detected; the power supply is capable of distinguishing between ground faults in at least two different locations, and when a fault is detected, the power supply signals the presence of the fault and its location, e.g., by timed blinking of the connected discharge light. These features are enhanced by a diagnostic analyzer for connection to the power supply.

Abstract: A power supply power supply circuit of the kind which includes a transformer having primary and secondary windings and an oscillator for driving the primary winding in a bi-directional fashion, suitable for driving gas discharge lighting such as neon signs, which prevents dangerous overvoltage output conditions and detects relatively low level ground fault currents. The transformer includes a clamp winding which is in proximity to and capacitively coupled to the secondary winding. The terminals of the clamp winding are connected to a current imbalance detection circuit for detecting imbalance between the current flowing into one clamp winding terminal and the current out of the other clamp winding terminal. In a ground fault condition, ground fault current flows in an unbalanced fashion into the clamp winding terminal(s), and through the capacitive coupling to the secondary winding.

Abstract: A refrigeration and active damper control circuit uses a single-pole thermostatic switch to control the damper motor for the fresh food compartment of a refrigeration unit. When the thermostatic switch is closed, the control circuit connects current from the electrical power source directly to the damper motor through the thermostatic switch; when the thermostatic switch is open, the control circuit connects current from the electrical power source through the evaporator fan motor and then through the damper motor. The damper motor has an electrical resistance substantially larger than that of the evaporator fan motor, so that during the latter series connection of the evaporator fan motor and damper motor, a sufficient voltage drop develops across the damper motor so that the damper will be closed by the damper motor.

Abstract: The drive train of an appliance timer includes a slip clutch formed of a triangular spring meshing with the outer flat surfaces of a hexagonal drive shaft. The slip clutch is incorporated into a drive pinion in the appliance timer drive train. Excessive torque causes the walls of the triangular spring to resiliently bend outward under rotational pressure from the drive shaft, permitting the drive shaft to rotate without rotating the drive pinion. When used in an icemaker, the slip provided by the clutch alleviates the need for an expensive, stallable motor.

Abstract: A transformer control circuit which includes a ground fault detection circuit that detects ground fault currents in the transformer secondary and delivers a ground fault detection signal to the primary circuit. This circuit derives power from the secondary winding and transmits the ground fault detection signal through an optical isolation barrier, thus avoiding the use of an auxiliary transformer. The ground fault detection circuit further includes safety features for detecting whether AC power is being supplied without earth ground being connected, and/or whether there is an undesired electrical connection between a transformer output connection and earth ground, which would defeat the ground fault detection circuit.

Abstract: A transformer housing includes a main compartment enclosing the transformer and an auxiliary compartment. The power source is connected to the primary windings in the auxiliary compartment and the electrical load is connected to the secondary windings in the main compartment. Insulating bushings mounted to the walls of the main compartment support the connections between the secondary windings and the load, maintaining these electrical connections a sufficient distance away from the walls of the housing, and each other, to substantially prevent electrical leakage from the connections to the housing or each other.

Abstract: An improved icemaker having a number of features, including: a dual-activated feeler bar switch which combines the motion of two cams to operate a single switch; an adjustable-duration water fill switch which is closed by rotating a connector between two contacts; switches mounted to make wiping contact so as to clean the contact area; a combination deflector which not only deflects ice removed by the ejector from the ice mold, but also supports and lifts a feeler bar to determine whether the ice storage bin is full; a clutch mounted between the motor and ejector bar to permit slip therebetween so as to avoid stalling the motor as the ejector bar presses upon ice in the mold; a manual start button for starting the motor, simplifying installation; and an anti-back mechanism in the icemaker drive train to prevent an installer from damaging the icemaker by rotating it backwards.

Abstract: An improved icemaker having a number of features, including: a dual-activated feeler bar switch which combines the motion of two cams to operate a single switch; an adjustable-duration water fill switch which is closed by rotating a connector between two contacts; switches mounted to make wiping contact so as to clean the contact area; a combination deflector which not only deflects ice removed by the ejector from the ice mold, but also supports and lifts a feeler bar to determine whether the ice storage bin is full; a clutch mounted between the motor and ejector bar to permit slip therebetween so as to avoid stalling the motor as the ejector bar presses upon ice in the mold; a manual start button for starting the motor, simplifying installation; and an anti-back mechanism in the icemaker drive train to prevent an installer from damaging the icemaker by rotating it backwards.

Abstract: A ballast for driving a gas discharge tube light with overvoltage protection and dimming. A clamp winding coupled to the internal DC power source prevents overvoltage of the secondary terminals by permitting induced current flow in the clamp winding if the clamp winding voltage exceeds that of the internal DC power source. The transformer core includes a shunt leg which supports a dimmer control winding. When the dimmer control winding is open-circuited, magnetic flux is shunted away from the secondary winding, reducing the light intensity; when the dimmer control winding is short-circuited, currents induce in the dimmer control winding prevent substantial of magnetic flux density and increase the light intensity.

Abstract: An oven latch mechanism for heat-cleaning ovens is disclosed. The latch mechanism employs a unidirectional rotating d.c. motor to automatically latch the oven door upon initiation of a heat-cleaning operation and to automatically unlatch the door after a heat-clean operation and after the oven has reached a predetermined lower temperature. The latch mechanism includes a latch arm which moves arcuately through a variety of positions. The latch member senses whether the door is open and follows a different path of motion accordingly. If the latch member senses an open door, it returns to an unlatched position.

Abstract: A resonant inverter is current mode-controlled with a transistor supplying current through a primary winding of a transformer. The cycle of operation includes conducting, resonating, and clamping portions of the cycle, with the transistor being turned on for the conducting portion. The resonating portion includes a storage capacitor connected to the primary winding and commences when current-responsive means of the transistor or first semiconductor turns on a second semiconductor, which in turn turns off the first semiconductor. During this resonating stage, the current in the primary winding reverses and stores energy in a storage capacitor. A clamping portion of the cycle includes a unidirectional conducting means or diode which conducts for a time for the excess energy stored in the tank circuit to return to the input and be stored in a filter capacitor.