Abstract:
A generator stator core through-bolt tensioning device that automatically tightens the nut on the through-bolts that hold together and compress laminate plates of the stator core in a high voltage generator. A controller receives a signal from a measuring device, such as a fiber Bragg grating that measures the strain on the bolt, and based on that signal determines whether the nut needs to be tightened. If the controller determines that tightening is necessary, it will cause the tensioning device to automatically tighten the nut while the generator is in service, and use the measuring device to provide feedback of the tensioning of the through-bolt to know when to stop the device from tightening the nut.
Abstract:
A generator stator core that includes a plurality of through-bolts extending through the stator core. Each through-bolt includes a threaded end on which is positioned a conical washer and a through-bolt nut, where the through-bolt nuts are tightened against the washers to compress laminate plates and hold the stator core together. The stator core further includes a through-bolt tension monitoring system including a fiber Bragg grating sensor mounted to one or more of the conical washers and being provided in at least one optical fiber. The monitoring system further includes a monitoring device providing an optical signal to each of the fiber Bragg grating sensors and receiving a reflected signal from the fiber Bragg grating sensors where the reflected signal provides an indication of strain on the washer to provide an indication of how tight the nut is on the through-bolt.
Abstract:
A method is provided for monitoring velocity of a fluid flow through a predetermined fluid flow space. A fiber optic conductor includes a flow measurement portion defining an elongated dimension extending across a portion of the fluid flow space. The fluid flow in the fluid flow space causes the measurement portion of the fiber optic conductor to flex in a direction transverse to the elongated dimension. Optical radiation is supplied to the fiber optic conductor, and optical radiation is received from the fiber optic conductor after the supplied optical radiation has passed through the measurement portion. The received optical radiation is analyzed to effect a determination of a flow velocity of the fluid flow.
Abstract:
Apparatus (12) to measure blade vibration in a gas turbine engine (8). An illumination source (20) generates a sequence of illumination bursts in a field of view capturing a passing rotating blade (10) of the gas turbine engine. An imager (22) generates image data including a series of images capturing views of the passing rotating blade. The images are exposed in response to respective illumination bursts. A controller (30) is configured to process the series of images to identify one or more vibration modes of the rotating blade.
Abstract:
A magnetic flux sensor for measuring the radial component of the magnetic flux impinging on a stator bar of a high voltage generator. The magnetic flux sensor includes a fiber Bragg grating formed in an optical fiber and enclosed within a magnetostrictive coating. The magnetostrictive coating responds to changes in magnetic flux by applying a strain on the fiber that changes the reflected wavelength of the Bragg grating that can be measured to provide a measurement of the flux. In one embodiment, one or more of the magnetic flux sensors is positioned directly within an insulating layer of the particular stator bar.
Abstract:
The claimed invention provides a blade vibration measuring system comprising a blade, a transmitter, a target with non parallel edges located on the blade shroud and a receiver. The present invention also provides a blade adapted for measuring blade vibration. Furthermore, the claimed invention provides a method for monitoring blade vibration.
Abstract:
A method for predicting a blade structure failure within a coupled blade structure including a plurality of blades supported for rotation on a rotor and a shroud structure coupling the blades. The method includes the steps of determining displacements of a plurality of predetermined circumferential locations on the shroud structure during rotation of the blade row, where the displacements are provided as a function of time relative to the periodic rotation of the shroud structure for time intervals that are integer multiples of rotor rotation. A signal characteristic related to vibrational mode and a nodal diameter of the shroud structure is derived based on the displacements of the circumferential locations on the shroud structure.
Abstract:
A method for measuring the differential emissivity between two sites on the surface of a body and the temperature of the two sites. The method includes a plurality of measurements of the infrared radiation arising from each of the two sites under a number of different conditions. Some of the measurements include irradiation by external infrared radiation at a known wavelength and intensity. The infrared radiation arising from each of the sites may include emitted radiation, reflected ambient radiation, and reflected external radiation. Additionally, the temperature determined using the method described can be used to calibrate infrared imaging devices used to inspect the entire body.
Abstract:
Apparatus and method for monitoring vibration levels in rotatable machinery (52). In one embodiment, a system (50) includes a source (66) for generating coherent radiation (70) and a first partially transmissive, partially reflective device (90) positioned to receive radiation (70) from the source (66) and transmit a part of the radiation there through. A second partially transmissive, partially reflective device (100) is mounted to the machinery (52), positioned to reflect a first signal (72) and transmit radiation (70) transmitted by the first device (90). A third device 104) is mounted to the machinery (52) and positioned to reflect radiation transmitted through the second device to provide a second signal (78). Circuitry (82, 86) is configured to generate an electrical signal based on a combination of the first and second signals (72, 78), and processing circuitry (114) provides a value indicative of vibration amplitude occurring in the machinery (52) based on the combination of the first and second signals. An embodiment of an associated method includes providing a first radiation signal (70) of a first frequency, deriving second and third radiation signals (78A, 78B) each having a time-varying Doppler shifting frequency relative to the first signal, and providing a value indicative of vibration amplitude occurring in the machinery (52) based on a combination of the second and third signals.
Abstract:
A method of measuring vibration in a bladed rotor structure with a vibration monitor. The vibration monitor includes a sensor for sensing passage of the sensor targets on radially outer portions of the blade structure, and the sensor generates signals corresponding to target passing events. An excitation structure is provided including at least one air jet for providing an excitation force to the blade structure. The blade structure is rotated about an axis of rotation and the air jet is driven in a circular path about the axis of rotation at a different rotational speed to apply a non-synchronous excitation force to the blade structure.