Abstract: A FBG strain sensor arrangement includes a sensor carrier of steel sheet to which a FBG strain sensor is fastened. A protective cover has a first part configured thin and narrow and bonded to the sensor carrier along an optical fiber so that the optical fiber lying underneath is fixed with a fiber Bragg grating on the sensor carrier. The protective cover is enlarged at each end portion of the optical fiber to thereby form a cavity underneath, with edges of the enlarged second part of the protective cover being bonded to the sensor carrier. Arranged in the cavity is an elastic filler which embeds the coupling points in a vibration damping manner. The protective cover with elastic filler accommodates thermal expansions and functions for dynamic measurements by the vibration damping.

Abstract: A weldable strain sensor includes a strain sensor having two end portions in signal communication with signal lines for transmitting a measurement signal. A sensor carrier extends in a direction of the strain sensor and is firmly connected to the strain sensor. The sensor carrier includes two end portions having slots to thereby form tongues defining tongue ends which are directed in opposition to each other. Integrally surrounding the strain sensor and the end portions thereof is a protective cover of solid plastic which is firmly connected to the sensor carrier. The protective cover is configured in a region of the strain sensor narrow and flat and in a region of coupling points of the strain sensor with the signal lines at least twice as wide and at least twice as high as in a region of the strain sensor.

Abstract: A FBG strain sensor arrangement includes a sensor carrier of steel sheet to which a FBG strain sensor is fastened. The FBG strain sensor includes an optical fiber having two end portions, with a Bragg grating provided between the end portions. An optical signal line is coupled to each end portion for transmission of a measurement signal. A protective cover has a first part configured thin and narrow and bonded to the sensor carrier along the optical fiber so that the optical fiber lying underneath is fixed with the Bragg grating on the sensor carrier. The protective cover is enlarged at each end portion of the optical fiber to thereby form a cavity underneath, with edges of the enlarged second part of the protective cover being bonded to the sensor carrier. Arranged in the cavity is an elastic filler which embeds the coupling points in a vibration damping manner.

Abstract: A weldable strain sensor includes a strain sensor having two end portions in signal communication with signal lines for transmitting a measurement signal. A sensor carrier extends in a direction of the strain sensor and is firmly connected to the strain sensor. The sensor carrier includes two end portions having slots to thereby form tongues defining tongue ends which are directed in opposition to each other. Integrally surrounding the strain sensor and the end portions thereof is a protective cover of solid plastic which is firmly connected to the sensor carrier. The protective cover is configured in a region of the strain sensor narrow and flat and in a region of coupling points of the strain sensor with the signal lines at least twice as wide and at least twice as high as in a region of the strain 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 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 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 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: Fiber Bragg gratings (FBGs) are particular suitable for measuring strain. However, a single parameter measurement is difficult to implement, since cross-sensitivity to temperature compels the use of an additional temperature reference, e.g. a strain-inactive FBG. The development of a passive athermal fiber Bragg grating strain gage is thus of particular interest since it renders optional the measurement of temperature, benefiting large scale system design and performance. In view of this need, a package for fiber Bragg gratings that enables strain measurements to be performed while canceling temperature sensitivity is disclosed. The proposed design is based on a structure composed of two parts, which can be made of the same material, having a defined length ratio that allows the adjustment of the temperature sensitivity to zero, providing athermal operation of the strain gage.