초록 ▼

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 matri

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.

대표청구항 ▼

[ What is claimed is:] [14.] Apparatus for determining frequencies and amplitudes of non-synchronous vibrations in blades on a rotating wheel, comprising:sensor means including a pair of probes spaced from each other about said wheel by a probe angle other than 180.degree. for generating data signal

[ What is claimed is:] [14.] Apparatus for determining frequencies and amplitudes of non-synchronous vibrations in blades on a rotating wheel, comprising:sensor means including a pair of probes spaced from each other about said wheel by a probe angle other than 180.degree. for generating data signals representative of actual times of arrival of said blades at said probes;processing means processing said data signals using Fourier analysis adjusted to correct for said probe angle of other than 180.degree. to generate outputs representing said frequencies and amplitudes of said non-synchronous vibrations; andoutput means presenting said outputs representing said non-synchronous vibrations.