Loading patent…
AssigneeElectric Power Research Institute, Inc.
InventorsGerald B. Kliman, Rudolph A. A. Koegl, Max W. Schulz, Jr., Stephen E. Grabkowski
Estimating the term…
A method and apparatus for detecting rotor faults in an induction motor. A flux sensor generates a flux signal corresponding to the magnetic flux at a predefined flux detection point external to the motor. A current sensor generates a current signal proportional to the current drawn by said motor. A time series of data points is stored, representing the values of the flux signal and the current signal over a period of time. The time series are transformed by FFT into a set of flux spectra and into a set of current spectra. Then the line frequency of the motor's power supply is determined by finding the maximum of the current spectra. Similarly, the slip frequency of the motor is determined by finding the maximum of the flux spectra in a predefined spectral range (e.g., below 2 Hz). The analysis of the rotor is then performed by comparing the amplitude of the current spectra, at a set of rotor fault harmonic frequencies, with specified fault threshold criteria. Each rotor fault harmonic frequency is a predefined function of the line frequency and the slip frequency. The presence of a rotor fault is denoted if the amplitude of any of said current spectra exceed a corresponding fault threshold criteria.
A method of detecting rotor faults in an induction motor, the motor including a rotor with a multiplicity of rotor bars, and a stator which draws current from a power supply, the method comprising the steps of:
Apparatus which detects rotor faults in an induction motor, the motor including a rotor with a multiplicity of rotor bars, and a stator which draws current from a power supply, comprising:
A method of detecting rotor faults in an induction motor, the motor including a rotor with a multiplicity of rotor bars, and a stator which draws current from a power supply, the method comprising the steps of:
Apparatus which generates rotor faults in an induction motor, the motor including a rotor with a multiplicity of rotor bars, and a stator which draws current from a power supply, comprising:
A method of detecting rotor faults in an induction motor, the motor including a rotor with a multiplicity of rotor bars, and a stator which draws current from a power supply, the method comprising the steps of:
Dependencies are inferred from the claim text.