Sundstrand Corporation

William M Spencer

Melvin C Jackovich

Joseph S Breit

James B Thom

A three phase inverter (10) in accordance with the invention includes a first phase inverter (12) producing a first phase AC output voltage from a DC power supply; a second phase inverter (14) producing a second phase AC output voltage which is displaced nominally 120.degree. from the first phase from the DC power supply; and a vector adding circuit (32), responsive to the first and second phases, for vectorially adding voltages proportional to output voltages from the first and second phases to produce a resultant voltage which is inverted to produce a third phase having an output voltage which is displaced nominally 120.degree. from the output voltages produced by the first and second phases.

DC to AC inverter and method for producing three phases from two input

A contactor (12) for controlling connection of a DC power supply to an electrical load (14) in includes a series circuit (19) disposed between a nonground DC potential and a load having first (20) and second (22) relays each having a pair of contacts (26), the first relay and the second relay having a conducting state when the pair of contacts are closed and a non-conducting state when the pair of contacts are open which control current flow between the DC power supply and the load with the states being controlled by control signals applied to the relays; a semiconductor switch (24) having a conductive state controlled by a control signal to turn on the semiconductor switch to connect the semiconductor switch in parallel with the contacts of the first relay and a non-conductive state controlled by a control signal to turn off the semiconductor switch to disconnect the terminals of the semiconductor switch; a fault sensor (50) coupled to the load for generating a signal in response to the load drawing current exceeding a threshold to cause the second relay to open to disconnect the load from the power supply; and a control signal generator (28) for generating the control signals of the switches.

Hybrid contactor for DC airframe power supply

A circuit for detecting the occurrence of a shorted diode in the rotating rectifier of a brushless alternator. A sensing circuit is responsive to the direction of current flow through the exciter field winding. A reversal of the current indicates that there is a shorted rectifier diode.

Detector for shorted rotating diode of a brushless alternator

A circuit for detecting the occurrence of a shorted diode in the rotating rectifier of a brushless alternator. A comparator has connected to it signals representing the base drive to the voltage regulator output transistor and the voltage at the terminal of the generator field winding connected with the collector-emitter circuit of the output transistor. The occurrence of a field winding terminal voltage of the order of the voltage at the anode of the diode which shunts the voltage regulator output transistor, in the absence of a drive signal to the transistor, indicates that there is a shorted rectifier diode.

This invention relates to a shorted diode protection system for a brushless alternating current generator of the type having an energizeable exciter field winding. The system includes a circuit arrangement for sensing the voltage difference across the exciter field and pairing the voltage difference with generator load current to thereby provide an output signal that falls within a predictable range of values over a normal generator load current range. The output signal is of such a nature that it falls within a higher range of values upon the occurrence of a shorted diode. Another circuit arrangement is responsive to the output signal such that whenever the output signal exceeds a preset value over the normal load current range, an output is generated that operates to cause the interruption of the exciter field.

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Rockford, IL, United States of America

William M Spencer