Sundstrand Corporation

Melvin C Jackovich

William M Spencer

James B Thom

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.

Generator shorted diode protection system

In a vehicle wherein power is applied to each track or wheel through a hydrostatic transmission and control system including: a displacement control unit for regulating each transmission; a steering control valve associated with each displacement control unit for modifying the operation of the displacement control unit; and a speed and direction control unit for applying hydraulic pressure to each of the displacement control units for controlling the basic direction and speed of the vehicle; wherein the maintenance of the desired direction of operation of the vehicle is enhanced by an electronic tracking control circuit that includes: means for measuring the actual speed of each track; a phase comparator for providing a signal indicating the difference in track speeds; an integrator for providing a signal proportional to the difference in speed as measured over time; and comparator circuits responsive to the integrator for triggering a solenoid control valve connected between the appropriate steering control valve and displacement control unit to open, thereby reducing the speed of the faster moving track in order to maintain the desired direction of operation. Either a straight line or curved path of operation for the vehicle can be selected by adjusting bias voltages applied to the integrator. Additional circuitry is provided to deactivate the electronic tracking control when either of the steering control valves is actuated.

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Stillman Valley, IL, United States of America

Melvin C Jackovich