Abstract: A solid state relay coupleable to first and second phase busses of an AC power source for switching power from the first and second phase busses to a load including a reactive component comprises: first and second power semiconductor switches connected in a series circuit configuration and coupleable to the first and second phase busses for switching power from the first and second phase busses to the load, each of the first and second power semiconductor switches controllably operative in conductive and non-conductive states; first and second power diodes coupled respectively across the first and second power semiconductor switches; and a control circuit for monitoring a voltage across the first and second phase busses and a current of the load, and for controlling the first and second switches to a conductive state based on the monitored voltage and to a non-conductive state based on the monitored load current. A counterpart method is also disclosed.

Abstract: A solid state relay coupleable to first and second phase busses of an AC power source for switching power from the first and second phase busses to a load comprises: first and second power semiconductor switches connected in a series circuit configuration and coupleable to the first and second phase busses for switching power from the first and second phase busses to the load, each of the first and second power semiconductor switches controllably operative in conductive and non-conductive states; first and second power diodes coupled respectively across the first and second power semiconductor switches; and a control circuit for monitoring a polarity relationship of the first and second phase busses and controlling the first and second switches between conductive and non-conductive states based on the monitored polarity relationship. A method of operating the solid state relay is further disclosed.

Abstract: A solid state relay coupleable to first and second phase busses of an AC power source for switching power from the first and second phase busses to a load including a reactive component comprises: first and second power semiconductor switches connected in a series circuit configuration and coupleable to the first and second phase busses for switching power from the first and second phase busses to the load, each of the first and second power semiconductor switches controllably operative in conductive and non-conductive states; first and second power diodes coupled respectively across the first and second power semiconductor switches; and a control circuit for monitoring a voltage across the first and second phase busses and a current of the load, and for controlling the first and second switches to a conductive state based on the monitored voltage and to a non-conductive state based on the monitored load current. A counterpart method is also disclosed.

Abstract: A solid state relay coupleable to first and second phase busses of an AC power source for switching power from the first and second phase busses to a load comprises: first and second power semiconductor switches connected in a series circuit configuration and coupleable to the first and second phase busses for switching power from the first and second phase busses to the load, each of the first and second power semiconductor switches controllably operative in conductive and non-conductive states; first and second power diodes coupled respectively across the first and second power semiconductor switches; and a control circuit for monitoring a polarity relationship of the first and second phase busses and controlling the first and second switches between conductive and non-conductive states based on the monitored polarity relationship. A method of operating the solid state relay is further disclosed.

Abstract: An aircraft fluid delivery device (10) including a piston assembly (20), a pilot assembly (22), and a control assembly (24). The control assembly (24) includes non-contact proximity sensors (S1, S2) that sense the position of the piston (28) and a controller (80) that controls the pilot assembly (22), and thus the piston assembly (20), based on information received from the sensors (S1,S2). Specifically, the controller (80) energizes a solenoid (72) to cause fluid to flow through the pilot assembly (22) into a large portion of the piston chamber (30) during the compression stroke of the piston (28). When the solenoid (72) is deenergized during the return stroke of the piston (28), or when the delivery device is electrically turned off, an ejector (60) in the pilot assembly (22) generates a vacuum on the pressure side of the wide portion of the piston chamber (30).

Abstract: An aircraft fluid delivery device (10) including a piston assembly (20), a pilot assembly (22), and a control assembly (24). The control assembly (24) includes non-contact proximity sensors (S1, S2) that sense the position of the piston (28) and a controller (80) that controls the pilot assembly (22), and thus the piston assembly (20), based on information received from the sensors (S1,S2). Specifically, the controller (80) energizes a solenoid (72) to cause fluid to flow through the pilot assembly (22) into a large portion of the piston chamber (30) during the compression stroke of the piston (28). When the solenoid (72) is deenergized during the return stroke of the piston (28), or when the delivery device is electrically turned off, an ejector (60) in the pilot assembly (22) generates a vacuum on the pressure side of the wide portion of the piston chamber (30).

Abstract: A current monitor includes a DC isolating amplifier circuit especially adapted for adjusting the set point of a comparator. The isolating amplifier circuit includes an operational amplifier generating a first current in response to an input voltage received by the operational amplifier. The first current is transmitted to a first optocoupler and a second optocoupler which are characterized by a first CTR and a second CTR, respectively. An output of the first optocoupler is fed back to an input of the operational amplifier while an output voltage of the second optocoupler is communicated to a set point circuit. The output voltage of the second optocoupler varies as a function of the product of the input voltage of the operational amplifier and a ratio between the first CTR and the second CTR.

Abstract: An all solid state timer-controller for the timed, sequential application of electrical current to loads within a circuit at high amperage, the circuit finding utility in the application of electrical current to de-icers employed aboard aircraft.

Abstract: In a circuit having an electro-mechanical relay, the contacts of which are subject to arcing, bridging across the electro-mechanical relay in a manner configured to begin conducting electrical current around the electro-mechanical relay prior to closing the electro-mechanical relay and to continue conducting electrical power around the electro-mechanical relay for a predetermined time after the onset of separation of contacts of the electro-mechanical relay pursuant to discontinuance of current flow through the electro-mechanical relay. An optical coupler is provided to ascertain a current flow through the relay coil effected to close the electro-mechanical relay contacts, and activates a shunt device in bridging electrical current flow around the electro-mechanical relay. The shunt device is provided to be substantially non-load carrying while the electro-mechanical relay is closed. Utility is found in protecting electro-mechanical relay contacts against damage due to arcing.

Abstract: In a circuit having a electro-mechanical relay the contacts of which are subject to arcing, a shunt across the electro-mechanical relay configured to begin conducting electrical current across the electro-mechanical relay prior to closing the electro-mechanical relay contacts and to continue conducting electrical power across the electro-mechanical relay for a predetermined time after the onset of separation of electro-mechanical relay contacts pursuant to discontinuance of current flow through the elecro-mechanical relay. An optical coupler is employed to detect the current flow through the relay coil and activate a shunt device to initiate current flow around the electro-mechanical relay. The shunt device is configured to be substantially non-current load carrying while the electro-mechanical relay is closed. Utility is found in protecting relay contacts against damage due to arcing.

Abstract: An overcurrent protection circuit wherein excessive current flow to current handling components triggers a programmable unijunction transistor which activates a crow-bar device to clamp off current flow through the current handling components. The overcurrent protection circuit finds utility in protecting solid state circuits from overcurrent situations, and is characterized by rapid response time on an order of less than one microsecond.

Abstract: An overcurrent protection circuit wherein excessive current flow to current handling components activates an optical coupler device which activates a crow-bar device to clamp off current flow through the current handling components. The overcurrent protection circuit finds utility in protecting solid state circuits from overcurrent situations, and is characterized by rapid response time on an order of less than one microsecond.

Abstract: Electrical circuitry for monitoring the current flow through resistance elements on the leading edge of an aircraft wing or horizontal stabilizer. The resistance elements are individually and sequentially activated for heating to thereby effect a de-icing or anti-icing function. The non-activated elements are sensed by the circuitry to determine inferentially if there is a predetermined current flow through the heating elements to achieve the intended de-icing or anti-icing function.