An abnormality detection device includes a vibration measurement value acquisition unit configured to acquire a measurement value of vibration of a rotation shaft, which is measured by each of shaft vibration sensors provided to be spaced apart in a diameter direction of the rotation shaft with respect to an outer circumferential surface of the rotation shaft at positions spaced apart in a shaft direction of the rotation shaft, for each rotation angle of the rotation shaft, a vibration vector calculation unit configured to calculate a vibration vector indicating a rotation angle at which a vibration of the rotation shaft is a maximum and a magnitude of the vibration on the basis of the measurement value of the vibration, and an estimation unit configured to estimate an abnormality occurrence position in the shaft direction of the rotation shaft on the basis of a time change in the vibration vector.

A controller for a gas turbine engine is disclosed. The controller is configured to measure a first rotational speed of a shaft of the engine at a first end of the shaft and to measure a second rotational speed of the shaft at a second end. The first end may be coupled to a turbine of the engine and the second end may be coupled to a compressor of the engine. The controller is further configured to determine a shaft twist angle as a function of the first rotational speed and the second rotational speed, determine whether the shaft twist angle is within a predetermined shaft health monitoring range, and record the shaft twist angle. The controller may be configured to generate a maintenance alert in response to determining that the shaft twist angle is within the predetermined shaft health monitoring range.

A controller for a gas turbine engine is disclosed. The controller is configured to measure a first rotational speed of a shaft of the engine at a first end of the shaft and to measure a second rotational speed of the shaft at a second end. The first end may be coupled to a turbine of the engine and the second end may be coupled to a compressor of the engine. The controller is further configured to determine a shaft twist angle as a function of the first rotational speed and the second rotational speed, determine whether the shaft twist angle is within a predetermined shaft health monitoring range, and record the shaft twist angle. The controller may be configured to generate a maintenance alert in response to determining that the shaft twist angle is within the predetermined shaft health monitoring range.

Systems and methods are provided for an aircraft propulsor configured to generate electrical power through a variable frequency generator in response to rotation of a gear train. The aircraft propulsor includes compensation circuitry. The aircraft propulsor further includes exciter circuitry that, when powered by an excitation signal, generates a magnetic field that interacts with a rotating variable frequency generator to generate electrical power. The exciter circuitry may be powered by at least a portion of the power generated by the variable frequency generator. The compensation circuitry may adjust the excitation signal to reduce the effect of torsional oscillation of the gear train and/or the variable frequency generator on the quality of power produced by the variable frequency generator.

Methods and systems for the absolute high-resolution measurement of angle of rotation of a shaft, which allow for concurrent measuring of axial displacement and/or encoded identification information, are disclosed. Included is a method for measuring characteristics of a rotating shaft comprising obtaining optical signals by optically probing one or more patterns having a leading edge and a series of symbols disposed at one or more circumferences of the shaft; oversampling the optical signals; measuring time of arrival for the leading edges and determining therefrom an amount of time between arrival of two or more of the leading edges; interpolating and extrapolating the amount of time between arrival of the leading edges; and determining therefrom one or more of shaft twist, angle of rotation and/or axial loading, translation, or displacement. The methods include optically probing a pattern disposed around the circumference of a shaft that comprises a series of wedge-shaped symbols.

Methods and systems for the absolute high-resolution measurement of angle of rotation of a shaft, which allow for concurrent measuring of axial displacement and/or encoded identification information, are disclosed. Included is a method for measuring characteristics of a rotating shaft comprising obtaining optical signals by optically probing one or more patterns having a leading edge and a series of symbols disposed at one or more circumferences of the shaft; oversampling the optical signals; measuring time of arrival for the leading edges and determining therefrom an amount of time between arrival of two or more of the leading edges; interpolating and extrapolating the amount of time between arrival of the leading edges; and determining therefrom one or more of shaft twist, angle of rotation and/or axial loading, translation, or displacement. The methods include optically probing a pattern disposed around the circumference of a shaft that comprises a series of wedge-shaped symbols.

The invention relates to the field of electric drive devices and electric machines, such as electric drive motors and electric generators for industrial applications, and more particularly to a method and an arrangement for identification of lateral vibration characteristics of an electric machine. The arrangement for identification of lateral vibration characteristics of an electric machine according to the present invention includes a frequency converter, one or more vibration sensors and an electric machine, wherein said frequency converter is arranged for producing torsional excitation, said torsional excitation effecting lateral vibration in said electric machine; and wherein said one or more vibration sensors include at least one lateral vibration sensor arranged for measuring the lateral vibration from said electric machine as excitation response and for producing lateral vibration data.

The invention relates to the field of electric drive devices and electric machines, such as electric drive motors and electric generators for industrial applications, and more particularly to a method and an arrangement for identification of lateral vibration characteristics of an electric machine. The arrangement for identification of lateral vibration characteristics of an electric machine according to the present invention includes a frequency converter, one or more vibration sensors and an electric machine, wherein said frequency converter is arranged for producing torsional excitation, said torsional excitation effecting lateral vibration in said electric machine; and wherein said one or more vibration sensors include at least one lateral vibration sensor arranged for measuring the lateral vibration from said electric machine as excitation response and for producing lateral vibration data.

A drive system of a gas turbine engine includes at least one drive shaft operable to rotate within the gas turbine engine, a phonic wheel coupled to the at least one drive shaft, a speed sensor operable to detect rotation of the phonic wheel indicative of rotation of the at least one drive shaft, and a processing system coupled to the speed sensor. The processing system is operable to detect a phonic wheel pulse train indicative of rotation of the at least one drive shaft via the speed sensor, determine a torsional mode of the at least one drive shaft based on the phonic wheel pulse train, and record one or more trends of the torsional mode indicative of a health status of the drive system.

A monitoring device and a method for detecting mechanical torsional oscillations in a rotor shaft of a turbine-generator system. Specifically, the monitoring device and a method for detecting mechanical torsional oscillations in a turbine-generator system having a plurality of, such as two, three, four, five, six or more, turbines that are interconnected by means of a common turbine shaft.