Abstract: A method for determining electrical and mechanical performance of a polyphase electric motor system comprises sensing the instantaneous current signal and the instantaneous voltage signal as a function of time for at least one electrical phase of the motor. The sensed current signals and the sensed voltage signals are both processed to provide an instantaneous power factor of at least one electrical phase of the motor as a function of time. The resulting power factor is used to determine the tonal real and the total reactive power of the motor as a function of time. The total real power and the total reactive power signals are bandwidth limited and time-limited. The filtered and time-limited, total real power is then cross-plotted as a function of the filtered and time limited, total reactive power signal, generating a performance diagram. The mechanical performance characteristics of the motor are then extrapolated from the performance diagram.

Abstract: An improved method and apparatus for detecting and identifying one or more resonantly vibrating blades of a turbine through the use of acoustic sensors imbedded in the stationary casing of the turbine is disclosed. The acoustic sensor signals are processed to separate the characteristic Doppler waveform from the accompanying random noise and periodic noise. Improved signal processing techniques which involve the evaluation of both an information-bearing resonant signal and its Hilbert transform via direct synthesis are disclosed.

Abstract: A novel system for determining the magnitudes of loads on rotating helicopter components from signals remotely measured on the helicopter fuselage is characterized by a processor which decomposes the measured signals into corresponding Fourier components and extracts selected components therefrom. A programming module performs a multiplication on the respective Fourier components to correlate the measured components with corresponding determinative parameter values. The parameter values are established in a calibration process which is characterized by determination of the independent values of a measured signal set using a Jones orthogonalization process. The signals output from the coefficient programming module are provided to a multiplying resolver which receives synthesized reference sinusoids from a digital processor and generates time dependent signal components therefrom. These signals are ultimately summed in an analog summer circuit whose output signal corresponds to the desired parameter signal.