Abstract: A train monitoring and reporting system in which each car of a multi-car train is provided with sensors to monitor brake, door, motor and other functions. A controller in each car sequentially and repetitively reviews the condition of each sensed function and evaluates the conditions to determine whether a fault condition exists. The evaluation result is stored and the review is continued and repeated. The lead car of the train repetitively and sequentially interrogates the storage units in each car for each type of fault condition, stores the responses to the interrogation and displays to the motorman any faults reported. The cars communicate through a multiplex data link system which connects the cars in series in a multiplex current loop. The number of times each fault occurs is counted, the count being then available for readout by maintenance personnel.

Abstract: A power circuit including an x and y inverter, an x and y constant voltage transformer, and a filtered d.c. input operable to provide a three phase sine wave output. The three phase outputs from the two transformers are a result of interconnections of the secondary windings of the transformer - in essence connecting the conventional two phase to three phase connections. The circuit is operable to provide a constant three phase output when a balanced load is applied. With an unbalanced load the phase of the output voltages of the two transformers are corrected relative to each other. A feedback circuit that includes an oscillator continuously samples the phase of the output voltage of each of the two transformers and adjusts the phase of one transformer output to that of the other.