Westinghouse Electric Corporation

Karl C Koch

Charles W Einolf, Jr

Robert M Oates

Shan C Sun

Harold B Shutterly

Paul F Rozelle

Carlo F Petronio

Roger E Ray

Pamela M Maynard-Nenno

Carlo F Peteronio

Russel W Gonnam

An apparatus for detecting turbine blade passing times includes a sensor for producing an input signal each time a blade passes the sensor. Automatic gain control circuitry including a digital multiplier, peak detector and error amplifier regulates the amplitude of the input signal. A zero-crossing detector produces an output signal each time the input signal crosses a reference axis. A pre-trigger comparator produces a gating signal coinciding with the expected arrival time of the blade at the sensor. A gating device is responsive to the gating signal for conducting output signals which occur during the expected arrival time of the blade at the sensor. A monostable vibrator produces a digital pulse coinciding with the time at which the blade passes the sensor.

Steam turbine blade arrival time processor with automatic gain control

An apparatus for detecting blade passing times includes a sensor for producing an input signal each time a blade passes the sensor. A zero crossing detector produces an output signal each time the input signal crosses a reference axis. A phase shifter shifts the phase of the input signal to produce a gating signal coinciding with the expected arrival time of the blade at the sensor. A gating device is responsive to the gating signal for conducting output signals which occur during the expected arrival time of the blade at the sensor.

Apparatus for precise detection of blade passing times in a steam turbine

The multiplexer in a multichannel, secure digital communication system repetitively embeds a sequence of byte length uniquely coded synchronizing signals in each of n successive frames of one channel of a multichannel, time multiplexed digital bit stream. Redundant protective relay data and associated parity check data are embedded in four of the n frames in a second, preferably adjacent channel, with the remaining of the n frames in the second channel containing additional of the uniquely coded synchronizing signals. The time multiplexed serial bit stream is transmitted to a remote station, preferably by fiber optic communications media. The most recent bits of the received serial bit stream equal in number to the number of bits spanned by the two channels in n frames are retained in n-1 serially connected serial in, serial out shift registers. Sixteen bit portions, a frame apart, of the retained most recent bits of the serial bit stream are applied to n serial in, parallel out shift registers. The parallel outputs of these shift registers corresponding to the frames of the two channels encoded with the synchronizing signals are compared with the sequence of uniquely coded signals stored in addresses in PROMs. When the compared signals match, which will occur once in every n frames, a synchronization signal is generated and the protective relay data and parity check data are read directly from the other parallel outputs of the serial in, parallel out shift registers. Similar rapid resynchronization of voice and data channels in the time multiplexed serial bit stream can be achieved by counting the number of bits in the bit stream from the generation of the synchronization signal in the relay protection channels to the beginning of the time slot for a selected voice or data channel.

Apparatus and method for secure digital communication

An optical receiver especially useful for digital fiber optic systems operating a high pulse rates, converts the pulsed current signal generated by a PIN diode into a pulsed voltage utilizing a current to voltage converter comprising an FET input transistor, a complimentary cascoded bipolar transistor, and a large feedback resistor to reduce noise while providing a wide band width and dynamic range. The pulsed voltage signal is amplitude limited in a limiting amplifier and passed through a low pass filter to remove excess bandwidth and further reduced noise before being applied to a high speed comparator which generates the digital output. The pulsed voltage signal is passed from the current to voltage converter to the limiting amplifier through an emitter follower coupling transistor to isolate the open loop gain of the current to voltage converter so that its band width will not be changed with load.

Fiber optic receiver

A circuit arrangement for monitoring ground faults to a normally ungrounded coil of a motor, the circuit arrangement including; a source of a low-level d.c. voltage, the source having first and second output terminals between which the d.c. voltage is established and a conductive connection being established between the first output terminal and the motor coil; a current responsive unit connected between a point at ground potential relative to the motor coil and the second output terminal of the source for producing an output signal proportional to the amplitude of current flow between the second terminal and ground; and a motor control unit connected for preventing operation of the motor when the output signal from the current responsive means reaches a selected value.

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Pittsburgh, PA, United States of America

Karl C Koch