Abstract:
Rotor slip of the induction motor (IM) is one of the key indicators used in the analysis of the technical condition of the asynchronous motor and the detection of its defects. In practice, the presence of built-in tachometers as part of IM is extremely rare, and their additional installation is a complex and expensive procedure. The paper compares non-invasive methods for determining the slip frequency of the IM rotor by vibration acceleration spectra, current spectra, and by consumed active power at various motor loads. Effects of belt drive and methods of its tension (spring-loaded and fixed) on distortion of spectra of signals measured on the motor are determined. The obtained results showed good convergence of indirect methods for determining rotor slip frequency with tachometer readings. The method of determining slip by the consumed active power showed good accuracy, with minimal requirements for computing power.
Keywords:induction motor, maintenance strategies, types of faults, monitoring and diagnosis, slip.
