Abstract: A generator slot wedge is described. The slot wedge includes a surface and further includes a strain gage. The strain gage is attached to the surface of the slot wedge. A method of determining the strain on the generator slot wedge of the generator via the strain gage is also described.

Abstract: A generator slot wedge is described. The slot wedge includes a surface and further includes a strain gage. The strain gage is attached to the surface of the slot wedge. A method of determining the strain on the generator slot wedge of the generator via the strain gage is also described.

Abstract: A sensor for detecting an amount of current flowing in a wire wherein displacement of a sensing mirror is used in an interferometer to enable determination of the amount of current. The sensor includes a magnetostrictive element located within a magnetic field formed by the wire. The sensor also includes a position sensor that detects a size increase of the magnetostrictive element. In addition, the sensor includes an amplifying device that amplifies the size increase of the magnetostrictive element by a predetermined amplification factor to provide an amplified size increase. Further, the sensor includes a displacement device that displaces the sensing mirror by an amount corresponding to the amplified size increase.

Abstract: A fiber optic sensing apparatus that may be used to sense one or more conditions of an electromotive machine is provided. A housing (20) encloses an optical fiber sensor (18). An optical fiber (19) extends into the housing through an opening formed in the housing. A fiber-affixing device (15) may be affixed to the optical fiber proximate the opening. The fiber-affixing device includes opposed bearing surfaces (30, 32) extending away from the optical fiber and disposed against opposed inner and outer surfaces (34, 36) of the housing surrounding the opening. The fiber-affixing device is effective to affix the optical fiber within the opening, thereby substantially improving the robustness and survivability of the optical fiber sensor.

Abstract: A sensing apparatus (20) based on fiber optics including fiber gratings for monitoring stator slot temperatures in an electromotive machine (10) is provided. The apparatus may include a dielectric strip (22) to be received in a gap between a first stator bar (16) and a second stator bar (18) in a stator slot (14). One or more optical fibers (24, 25) may be disposed in the dielectric strip and extend along a longitudinal axis of the dielectric strip. A plurality of sites 28 in the optical fiber include a respective fiber Bragg grating arranged to have a respective optical response in a wavelength spectrum indicative of a value of temperature at the grating site.

Abstract: A fiber optic sensing apparatus that may be used to sense one or more conditions of an electromotive machine is provided. A housing (20) encloses an optical fiber sensor (18). An optical fiber (19) extends into the housing through an opening formed in the housing. A fiber-affixing device (15) may be affixed to the optical fiber proximate the opening. The fiber-affixing device includes opposed bearing surfaces (30, 32) extending away from the optical fiber and disposed against opposed inner and outer surfaces (34, 36) of the housing surrounding the opening. The fiber-affixing device is effective to affix the optical fiber within the opening, thereby substantially improving the robustness and survivability of the optical fiber sensor.

Abstract: A circular fiber hoop for supporting one or more fiber optic cables, especially fiber optic cables for an optical sensor provided within a pressurized enclosure of a power generator. The fiber hoop is a single piece member including a center mandrel positioned between opposing side guards. The fiber optic cable is wound around the mandrel between the side guards. An end of the fiber optic cable including the sensor is optically coupled through a union connector to another optical fiber, where the union connector is mounted to one of the side guards so that it is separated from the wound mass of the fiber cables. The wound mass of the fiber cable on the mandrel is then enclosed in a suitable tape.

Abstract: A sensing apparatus (20) based on fiber optics including fiber gratings for monitoring stator slot temperatures in an electromotive machine (10) is provided The apparatus may include a dielectric strip (22) to be received in a gap between a first stator bar (16) and a second stator bar (18) in a stator slot (14) One or more optical fibers (24, 25) may be disposed in the dielectric strip and extend along a longitudinal axis of the dielectric strip A plurality of sites 28 in the optical fiber include a respective fiber Bragg grating arranged to have a respective optical response in a wavelength spectrum indicative of a value of temperature at the grating site

Abstract: A circular fiber hoop for supporting one or more fiber optic cables, especially fiber optic cables for an optical sensor provided within a pressurized enclosure of a power generator. The fiber hoop is a single piece member including a center mandrel positioned between opposing side guards. The fiber optic cable is wound around the mandrel between the side guards.

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 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 sensor includes a housing adapted to be secured to a component within a system to be monitored by the sensor, an optical fiber, and a membrane spring assembly. The optical fiber includes a sensing portion containing a fiber Bragg grating that is able to undergo expansion and contraction resulting from movement of the optical fiber at a second location relative to a first location. The membrane spring assembly includes a membrane disc, wherein movement of a central portion thereof causes corresponding displacement of the optical fiber at the second location to cause expansion and contraction of the sensing portion of the optical fiber containing the fiber Bragg grating, which expansion and contraction effects a change in a light wavelength reflected by the fiber Bragg grating. The light wavelength reflected by the fiber Bragg grating can be used to measure movement of the central portion of the membrane disc.

Abstract: A fiber Bragg grating (FBG) based sensor is used as a strain sensing element to determine frame foot loading of a generator. Three FBGs may be used in tandem to form a basic Frame Foot Loading Module (FFL Module). Two modules are fixed on each vertical support gusset at the corner of the generator frame, with one module on the front of the gusset and a second module on the back of the gusset. Thus, each gusset may be instrumented with six FBG strain gauges or sensors. The gussets are chosen on each of the four corners of the generator. For two-pole generators the first three gussets at each corner may be used and, for four-pole generators the first four gussets may be used.

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: 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: A fiber Bragg grating (FBG) based sensor is used as a strain sensing element to determine frame foot loading of a generator. Three FBGs may be used in tandem to form a basic Frame Foot Loading Module (FFL Module). Two modules are fixed on each vertical support gusset at the corner of the generator frame, with one module on the front of the gusset and a second module on the back of the gusset. Thus, each gusset may be instrumented with six FBG strain gauges or sensors. The gussets are chosen on each of the four corners of the generator. For two-pole generators the first three gussets at each corner may be used and, for four-pole generators the first four gussets may be used.

Abstract: A system and method for monitoring the condition of a vibration sensor in a system. Vibrations are received in the system at one or more vibration sensors. Sensor data is output by the vibration sensor(s). The sensor data includes data representative of the vibrations in the system and data representative of a natural frequency of the corresponding vibration sensor. The sensor data output from the vibration sensor(s) is monitored, and upon a change in the data representative of the natural frequency of a vibration sensor, that vibration sensor is flagged.

Abstract: A component sensing system for monitoring the condition of ceramic tiles in a combustion chamber of a gas turbine engine. The sensing system includes an optical fiber that is mounted to the component being monitored, for example, the ceramic tiles in the gas turbine combustion chamber. The optical fiber can be formed in any suitable orientation or configuration, such as a meandering or serpentine orientation. The fiber is optically coupled to a Brillouin signal analyzer that provides an optical pulse to the sensing section of the fiber and detects Brillouin backscattering from the fiber as the pulse travels along the fiber. The frequency of the Brillouin backscattering signal is monitored relative to the distance along the sensing section of the fiber. A rise in temperature at a location of the fiber shows up in the analyzer as an increase in frequency of the backscattered signal.

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.