Abstract: An aircraft power supply for providing DC power with improved power quality characteristics. The aircraft power supply includes a transformer control system that can use closed-loop feedback from a DC power output to control switches that can short primary windings turns of a step-down transformer. By shorting turns in the primary, the transformer control system can control or manipulate the turns ratio in the transformer and compensate for decreases in the DC power output.

Abstract: An aircraft power supply for providing DC power with improved power quality characteristics to the aircraft. According to one embodiment, the aircraft power supply includes an input filter, a step-down transformer, one or more rectifier networks, and an output filter with a voltage modulation attenuator to passively improve power quality characteristics. The voltage modulation attenuator may use a certain arrangement of inductors, capacitors and diodes to reduce voltage transients in the aircraft power supply.

Abstract: A switching assembly is disclosed for a high voltage aircraft ignition system. The switching assembly includes a ceramic substrate and switch die that includes an anode bonded to an electrical pad on the ceramic substrate. The switch die includes a semiconductor device having a plurality of interleaved gates and cathodes, and includes a ceramic cap having at least one gate pad connected to the gates and at least one cathode pad connected to the cathodes. The switching assembly includes leads connected to the gate pad, the cathode pad, and the electrical pad on the substrate. The switch die and a portion of the leads are potted to form the completed assembly.

Abstract: A power supply unit that provides uninterrupted power to an aircraft power bus during switchovers of the aircraft bus from one power source to another. The power supply unit includes circuitry to distinguish between loss of bus power due to switchovers between power sources and loss of bus power due to shutdown of the aircraft. The power supply unit includes a low voltage lockout circuit to interrupt the supply of power when the aircraft bus voltage falls below a minimum value.

Abstract: A multi-phase AC-DC aircraft power converter having an input filter, power transformer, rectifier, output filter, and dummy load that provides improved voltage regulation across a range of output current loads. The transformer includes a primary and a pair of secondary windings. The input filter receives multi-phase AC input power and is connected to supply filtered input power to the primary of the transformer, with the secondary windings being connected to the rectifier. The rectifier provides a DC output that is connected to the output filter. The dummy load is connected at the output filter and is designed to draw sufficient current from the DC output such that the converter operates at a substantially linear I-V characteristic across a range of loads extending from a low load of less than 5 Amps to a high load of greater than 50 Amps.

Abstract: A partitioned exciter system for use with an igniter in an aircraft engine. The exciter has low-energy charging circuit and a high-energy discharge circuit that are remotely located from each other and that are connected by a low-energy coaxial cable. The charging circuit can be located within the aircraft fuselage and the discharge circuit mounted at the engine. The discharge circuit contains passive components that do not need special environmental protection, and the remotely located charging circuit can utilize existing electrical circuitry protection measures already in place in the fuselage to protect against lightning and other potentially-damaging environmental factors. Also disclosed is a housing arrangement for the discharge circuit that allows it to be directly attached to the igniter.

Abstract: An air-cooled ignition lead for use with aircraft engines to conduct high voltage ignition pulses between an exciter and an igniter. The ignition lead includes a center conductor covered by an insulation jacket for electrical isolation. Radially spaced outwardly from the insulation jacket is a flexible conduit that has sufficient structural integrity to resist collapsing inwardly. The insulation jacket and conduit define an airflow path therebetween that is used for conducting air through the lead. An innerbraid is located over and supported by an outer surface of the flexible conduit, and this location of the innerbraid prevents it from collapsing over time and obstructing the airflow passage that extends on the inner side of the flexible conduit. The innerbraid can be used as a return path conductor that provides a return current path and/or EMI shielding. Covering the innerbraid is an outerbraid to protect the lead against external damage.

Abstract: An air-cooled ignition lead for use with aircraft engines to conduct high voltage ignition pulses between an exciter and an igniter. The ignition lead includes a center conductor covered by an insulation jacket for electrical isolation. Radially spaced outwardly from the insulation jacket is a flexible conduit that has sufficient structural integrity to resist collapsing inwardly. The insulation jacket and conduit define an airflow path therebetween that is used for conducting air through the lead. An innerbraid is located over and supported by an outer surface of the flexible conduit, and this location of the innerbraid prevents it from collapsing over time and obstructing the airflow passage that extends on the inner side of the flexible conduit. The innerbraid can be used as a return path conductor that provides a return current path and/or EMI shielding. Covering the innerbraid is an outerbraid to protect the lead against external damage.

Abstract: An ignition lead that includes at least one terminal assembly having a replaceable terminal contact that provides a simple means of replacing worn contacts without removal and replacement of the entire ignition lead. The terminal assembly includes the replaceable contact which threads onto a contact body located within a tubular insulator. A retaining ring attaches to the contact to hold the insulator in place over the contact body. The contact can include a groove that extends around the contact to receive the retaining ring. Replacement of the contact involves removing the retaining ring from the groove in the contact, sliding the insulator off the terminal assembly, unthreading the worn contact, threading on a replacement contact, reassembling the insulator onto the assembly, and then securing the insulator in place by snapping the retaining ring back into the groove on the replacement contact.

Abstract: A partitioned exciter system for use with an igniter in an aircraft engine. The exciter has low-energy charging circuit and a high-energy discharge circuit that are remotely located from each other and that are connected by a low-energy coaxial cable. The charging circuit can be located within the aircraft fuselage and the discharge circuit mounted at the engine. The discharge circuit contains passive components that do not need special environmental protection, and the remotely located charging circuit can utilize existing electrical circuitry protection measures already in place in the fuselage to protect against lightning and other potentially-damaging environmental factors. Also disclosed is a housing arrangement for the discharge circuit that allows it to be directly attached to the igniter.

Abstract: An ignition lead that includes at least one terminal assembly having a replaceable terminal contact that provides a simple means of replacing worn contacts without removal and replacement of the entire ignition lead. The terminal assembly includes the replaceable contact which threads onto a contact body located within a tubular insulator. A retaining ring attaches to the contact to hold the insulator in place over the contact body. The contact can include a groove that extends around the contact to receive the retaining ring. Replacement of the contact involves removing the retaining ring from the groove in the contact, sliding the insulator off the terminal assembly, unthreading the worn contact, threading on a replacement contact, reassembling the insulator onto the assembly, and then securing the insulator in place by snapping the retaining ring back into the groove on the replacement contact.

Abstract: An exciter circuit for firing one or more igniter plugs in an aircraft ignition system. The exciter circuit includes an input node capable of receiving an alternating-current (AC) voltage with a variable frequency and amplitude, a pair of tank capacitors used as energy storage devices, a charging circuit for charging the tank capacitors, a discharge circuit for providing spark energy from the capacitors to two igniters, and a spark gap to initiate the discharge once the capacitors have been charged to a sufficient voltage. The charging circuit includes a step-up ferro-resonant transformer network and a full-wave rectifier. The transformer network includes a saturating transformer, a choke coil in series with the transformer primary, and one or more tuning capacitors connected to a center tap on the primary.

Abstract: An exciter circuit for firing one or more igniter plugs in an aircraft ignition system. The exciter circuit includes an input node capable of receiving an alternating-current (AC) voltage with a variable frequency and amplitude, a pair of tank capacitors used as energy storage devices, a charging circuit for charging the tank capacitors, a discharge circuit for providing spark energy from the capacitors to two igniters, and a spark gap to initiate the discharge once the capacitors have been charged to a sufficient voltage. The charging circuit includes a step-up ferro-resonant transformer network and a full-wave rectifier. The transformer network includes a saturating transformer, a choke coil in series with the transformer primary, and one or more tuning capacitors connected to a center tap on the primary.

Abstract: An inductive ignition circuit (10) especially adapted for use with micro-turbine and other small-sized turbine engines such as are used in electric generators. The inductive ignition circuit (10) includes a flyback transformer (14), a drive circuit (16) for energizing the primary (22) of the transformer (14), and a control circuit (18) that temporarily disables the drive circuit (16) once the transformer primary (22) has been sufficiently energized. The drive circuit includes a switching transistor (20) which is biased on to draw current through the primary (22). The control circuit (18) includes two feedback circuits (42,44), one of which initiates disabling of the transistor (20) to cause the transformer flyback and the second of which sets the spark rate. The first feedback circuit (42) monitors the primary current and disables the transistor (20) once the current exceeds a pre-selected level.