METHOD OF THE ASYNCHRONOUS ELECTRIC MOTORS ROTORS SHORT-CLOSED WINDINGS RODS BREAKS DETECTION Russian patent published in 2018 - IPC G01R31/34 

FIELD: engines.

SUBSTANCE: invention relates to the field of the asynchronous electric motors technical condition monitoring and can be used to detect of rotors windings rods breakages. Essence: detecting the external magnetic field induction radial component by a sensor mounted on the motor housing in the area of the stator core length middle part. Determining the detected signal amplitude spectrum, the amplitude spectrum maximum and the corresponding to it frequency, which is close in value to the network frequency. Determining the network frequency exact value, the rotor slip, the harmonics frequencies and amplitudes values, which are characteristic for the damaged rotor winding. In the detected signal, the network frequency exact value is determined by the signal recording time autocorrecting method. Removing the harmonics with the network frequency from the signal. Determining the first harmonic upper and lower lateral bands frequencies values from the rotor eccentricity by the signal recording time autocorrecting method. Rotor slip is determined by the network frequency exact value and the first harmonic upper and lower lateral bands frequencies values from the rotor eccentricity. Then, calculating the first five harmonics upper and lower lateral bands frequencies from the rotor fictitious winding, which are taken as harmonics individual to the rotor damaged winding, excluding the rotor fictitious winding harmonic upper lateral band, which order is equal to the number of the motor pole pairs, as well as harmonics lateral bands from the rotor fictitious winding, which frequencies coincide with the rotor eccentricity first-order harmonic upper or lower side bands frequencies. By the signal recording time autocorrecting method, determining these harmonics side bands amplitude values. From the obtained amplitudes values, the signal average power is calculated, compared with the threshold value and generating a signal about the rotor winding damage presence or absence.

EFFECT: technical result: increase in the rods breaks detection reliability and convenience.

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