Abstract: A monitoring system for measuring the gap between a turbine blade and a stationery component of a turbine, includes an insertion probe having a sensor which is moved radially within the gap to a pre-selected distance from the turbine blade as measured by the sensor's output. The distance the sensor moved from a reference point to arrive at the pre-selected distance from the blade is also monitored and the gap between the fixed turbine component and the blade is determined from these measurements.

Abstract: A system (90) for measuring the gap (16) between a rotating blade (14) and a stationary component (12) of a turbo-machine, including an eddy current coil (30) and an eddy current tester (91). The eddy current tester may excite the coil in a pulsed eddy current testing mode. The coil is positioned in a stationary portion (12) of a turbo-machine traversed by a rotating blade and the eddy current tester is coupled to the eddy current coil to provide an indication responsive to a distance between the blade and the stationary portion as the blade traverses the position. The coil may be mounted in a frangible ceramic pill (70) movably disposed in a housing (74). The coil is positioned near the turbine blade, the coil is excited with a voltage step function (120), and the response (122) of the coil to the step function is detected and processed to determine the proximity of the blade.

Abstract: A monitoring system for measuring the gap between a turbine blade and a stationery component of a turbine, includes an insertion probe having a sensor which is moved radially within the gap to a pre-selected distance from the turbine blade as measured by the sensor's output. The distance the sensor moved from a reference point to arrive at the pre-selected distance from the blade is also monitored and the gap between the fixed turbine component and the blade is determined from these measurements.

Abstract: Non-synchronous vibrations in blades on a rotating wheel, such as a turbine wheel, are measured using Fourier analysis adjusted to correct for uneven sampling produced by a pair of probes spaced from each other about the wheel by a probe angle (PA) other than 180.degree.. The Fourier transform matrix is phase shifted by an amount which is a function of the PA which is other than 180.degree., and the harmonic in which the mode of non-synchronous vibration is expected to be found. A scaling factor in the form of an inverse correction factor is applied to the frequency spectra produced by the phase shifted Fourier transform matrix to generate an output representative of the frequency and amplitude of the true excitation frequency which can be presented on a display.

Abstract: This invention includes a detection system that can determine if a turbine component, such as a turbine vane or blade, has exceeded a critical temperature, such as a melting point, along any point along the entire surface of the vane or blade. This system can be employed in a conventional combustion turbine having a compressor, a combustor and a turbine section. Included within this system is a chemical coating disposed along the entire interior surface of a vane or blade and a closed loop cooling system that circulates a coolant through the interior of the vane or blade. If the temperature of the vane or blade exceeds a critical temperature, the chemical coating will be expelled from the vane or blade into the coolant. Since while traversing the closed loop cooling system the coolant passes through a detector, the presence of the chemical coating in the coolant will be sensed by the system. If the chemical coating is detected, this indicates that the vane or blade has exceeded a critical temperature.

Abstract: A passive blade vibration monitor sensor for determining an arrival time of a blade of a combustion turbine during operation, the sensor includes an optical lens which receives infrared radiation generated by the blade of the turbine and generates a sensor signal from the received infrared radiation, the sensor signal indicating an arrival time of the blade of the combustion turbine. Target material having an emissivity lower than the emissivity of the blade may be placed on the blade to enhance sensor sensitivity especially in shrouded blade environments.

Abstract: A method for monitoring turbine blade vibrations comprises the step of transmitting a continuous wave of microwave energy toward a rotating row of blades. Each passage of an individual blade tip through the path of the continuous wave produces a signal indicative of the time at which each passage occurs. The signal is then monitored and analyzed to detect blade vibrations. The signal can be based on a standing wave or a reflected wave.

Abstract: A method for determining a beat frequency in a vibration sensing system attached to an electrical generator comprises the steps of (a) generating a vibration signal indicative of a vibrational frequency and amplitude of the generator; and (b) obtaining a beat frequency from the vibration signal by storing and processing time interval data representing the time intervals between zero crossings of the vibration signal. A generator 10, optical vibration sensor 12, and computer 14 constitute the vibration sensing system 16. The computer is programmed to analyze the time interval data to obtain the beat frequency.

Abstract: The present invention monitors RF emissions within a turbine generator. A coupling device provides a connection between preexisting thermal sensor leads and an RF monitor. Preexisting thermal sensor leads are connected to thermocouples and resistance temperature detectors during manufacture of the turbine generator. The RF monitor is used in the present invention to monitor RF emissions flowing in the thermal sensor leads thereby avoiding a need to retrofit RF sensors on the generator. The present invention also provides a capacitive coupling means between the thermal sensor leads and the RF monitor. The present invention also provides an inductive means to reduce interference from RF emissions having sources external to the generator.

Abstract: Apparatus for automatically cleaning shaft grounding devices in rotating machinery to reduce or eliminate the need for on-line servicing of the grounding devices. When a monitoring system for the grounding devices signals that an excessive electrical charge is present on the shaft, a cleansing material is sprayed at the interface of the grounding device with the shaft to remove any contaminants for the electrical insulating material between the bearings and the rotating shaft, and to re-establish the grounding path from the shaft. Voltage discharge from the shaft to the bearings through the bearing lubricating oil is thereby prevented. Alarm delay of the shaft ground monitoring device allows the apparatus to function automatically, obviating the need for on-servicing by plant personnel or unnecessary shut down of the machinery.

Abstract: A brush assembly for providing contact between a grounding brush and a rotating shaft, in which the noncontact time associated with brush bounce is reduced. A brush is provided which is fixed to a pivotable arm, with a bias force applied to the arm, such that when the brush is bounced from a shaft as a result of vibration or shaft wobbling, the bias force will reestablish contact between the brush and shaft. Rolling contact between a negator spring and the arm is also provided for reducing friction associated with contact between the spring and pivotable arm. Due to the reduced friction provided by the rolling contact, and more significantly by the pivotal mounting of the arm to which the brush is fixed, the response of the assembly in reestablishing contact with the shaft is greatly improved.

Abstract: Both a system and method are provided for detecting and locating a leak in the housing of the steam turbine components of an electric generator of the type that are connected to a vacuum pump that generates a negative pressure to remove air from the steam system, comprising a source of tracer gas for releasing a quantity of gas at potential leak locations on the exterior of the housings, a saturatable tracer gas detector having an inlet port in fluid communication with an outlet of the vacuum pump for detecting a flow of tracer gas associated with a selected minimum leak condition and for generating an electrical signal corresponding to this condition, an electrically controllable butterfly valve located upstream of the inlet port of the tracer gas detector for regulating the amount of tracer gas that flows into the detector, and a control assembly including a microprocessor that is electrically connected to both the tracer gas detector and to the valve for preventing a saturating flow of tracer gas from ente

Abstract: The present invention provides a valve control apparatus which can be programmed to deliver a desired flow of gas. A valve 22 is connected to a stepper motor 28 which is controlled by a computer 32 to open or close the valve in steps within a gas flow line 24 to deliver a desired rate of flow. A flowmeter 30 is provided along the gas flow line 24 for measuring the flow and inputting this flow to the computer 32. The computer 32 calculates rate of flow information obtained from the flowmeter 30 and controls the stepper motor 28 to open or close the valve 22 as necessary in accordance with the received rate of flow information and a desired rate of flow preprogrammed into the computer 32. As a result, a precise desired rate of flow can be obtained. Also, position indicators 34 may be added to the valve 22 to indicate when the valve 22 is completely open or completely closed. The valve 22 may be provided with a return spring 36 to automatically close the valve 22 in the event of a power loss.

Abstract: A sensor produces a signal indicative of the actual arrival time of each turbine blade at the sensor. A first circuit is responsive to the sensor for producing digital data representing the actual arrival time of each blade at the sensor. A second circuit establishes expected arrival times for each blade at the sensor. A third circuit is responsive to the digital data for generating a plurality of data entries each representing the difference between the actual arrival time and the expected arrival time. A fourth circuit stores the data entries in a first string having a plurality of dummy entries at the beginning thereof and at the end thereof and inserts into the string space saver characters in the event that the data entry for a particular blade is not produced. A fifth circuit establishes a running average value, over a plurality of data entries, for each data entry. The running average value is representative of common mode vibration.

Abstract: An optical vibration sensor is automatically calibrated by extracting a beat frequency vibration signal from a vibration signal produced by the optical vibration sensor, computing a resonant frequency of the optical vibration sensor using the beat frequency which has been extracted, and calibrating the optical vibration sensor based on the resonant frequency computed. The calibration method continuously compensates for changes in the resonant frequency due to temperature and mechanical changes of the optical vibration sensor. The optical vibration sensor is physically attached to an end-winding of an electrical generator.

Abstract: Both a system and method is provided for detecting faults in the insulating interface disposed between the shaft of a generator, and the bearings and seals that rotatably support it that generally comprises a transformer for selectively inducing an alternating electric potential into the shaft while the shaft is stationary, and a voltage meter for detecting whether the transformer-induced voltage is transmitted across the insulating interfaces. The number of wire windings used in the transformer of the system is preferably chosen so that the ac voltage induced in the shaft has substantially the same characteristics as the ac voltage induced by dissymmetry currents when the shaft is rotated by the turbines which drive the electric generator. The system of the invention is capable of not only detecting the existence of an insulation failure, but also its exact location so that only the defective portion of the insulation need be repaired.

Abstract: A device for detecting a ground fault in a winding mounted to rotate with the rotor of a machine, in which an electric potential is present across the winding during machine operation, the rotor is grounded and the winding is normally insulated from ground, the device including: a current responsive light emitting element mounted to rotate with the rotor and electrically connected between the winding and the rotor; and a light responsive detector fixed in a position relative to the machine and having a field of view which is traversed by the light emitting element during a portion of each revolution of the rotor.

Abstract: A fluid conduit composed of: two pipe sections each having a longitudinal axis and a connecting end, each pipe section including a cylindrical main portion, an annular flange located at the connecting end and extending radially outwardly from the main portion, and a thin annular disk located at the connecting end, extending radially outwardly from the flange and having an outer periphery, the pipe sections being assembled together at the connecting ends with the disks in contact with one another; and a mass of welding metal sealing the outer peripheries of the disks together.Such a connection can be broken by cutting off outer peripheral regions of the disks along a circular cutting line.

Abstract: An ultrasonic cleaning apparatus and method is provided for a venturi flow nozzle which is mounted in a pipe having fluid flowing therethrough. The apparatus includes a plurality of ultrasonic transducers mounted in openings provided upstream of the venturi flow nozzle inlet. The transducers transmit ultrasonic waves directly into and thereby excite the fluid flowing through the venturi flow nozzle and create cavitation which cleans the nozzle. Additional transducers are preferably provided in the throat area of the venturi flow nozzle. In alternative embodiments, the transducers are mounted in high and low pressure taps associated with the venturi flow nozzle such that the transducers directly transmit ultrasonic waves into fluid flowing into the high and low pressure taps. The transducers may be mounted flush with the interior of the pipe or venturi flow nozzle, or the transducers may be mounted at a position spaced therefrom in the high and low pressure tap piping.

Abstract: A method and apparatus which indicates an actual arc occurrence only if a voltage or current of a generator neutral lead exceeds a specified threshold amplitude, and is followed by a second RF signal again exceeding the threshold amplitude and occurring within a specified time period.