Induction Motor Rotor Defect Diagnosis Device, Method and Medium

Abstract

The invention discloses a rotor defect diagnosis device, method and medium of an induction motor, and the medium stores a computer-readable program for implementing the method. A rotor defect diagnosis device for an induction motor includes a voltage supply unit, a current measurement unit, a reactance calculation unit, and an eccentricity diagnosis unit. The voltage supply part supplies a single-phase voltage to the induction motor; the current measurement part measures the current supplied to the induction motor from the supply voltage; the reactance calculation part calculates the reactance of the induction motor using the voltage supplied to the induction motor and the measured current during the rotor rotation of the induction motor; The eccentricity diagnosis unit diagnoses the air gap of the induction motor as eccentricity when the calculated reactance value during one rotation of the induction motor rotor is always larger than the preset reactance value. With this structure, the rotor defect diagnosis device for an induction motor of the present invention is applicable to induction motors in any state, and can easily diagnose an eccentric state of an induction motor without expensive special equipment.

Description

technical field [0001] The present invention relates to an electric device, and in more detail, relates to a device and method for diagnosing the state of a motor. Background technique [0002] figure 1 It is a figure which schematically shows the structure of an induction motor. Such as figure 1 As shown, in the induction motor, voltage and current are applied to the winding 3 of the stator, so that the magnetic flux Φ generated in the stator core 1 s A current is generated on the bar 4 of the squirrel-cage rotor 2, thereby generating a magnetic flux Φ r . [0003] At this time, if an input power supply with a phase difference of 120° is applied to the three-phase winding of the stator, the stator magnetic flux Φ s It will rotate at a certain speed according to the input power, which is called a rotating magnetic field. [0004] The squirrel-cage motor operates by torque τ induced based on the mutual relationship between the magnetic flux generated in the stator and t...

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Problems solved by technology

[0032] However, in the case of low-frequency components, it can only be diagnosed when mixed eccentricity is present. High-frequency components are usually more suitable for static, dynamic, and mixed eccentric faults than low-frequency components. However, the number of rotor slots (R) needs to be known, and specific faults cannot be detected. Defects when the number of poles - the number of rotor slots (p-Rrelation)

[0033] Moreover, this frequency analysis method needs to store a large amount of data. If the load changes during operation and the speed and slip change, it is difficult to detect the accurate fault frequency.

In addition, due to the influence of a specific load (load torque oscillation), when the eccentric frequency of the void overlaps, it also has the disadvantage of being difficult to distinguish

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