Online fault diagnosis of large electrical machines using vibration signal-a review

Large electrical machine has been extensively used in power plants and industries. The overhaul for large electrical machine is a costly process; also, unexpected stoppage of product line in factories due to fault leads to huge economical loss. Different methods have been so far proposed for fault diagnosis of large electrical machines. This paper provides comprehensive review of prevalent faults in large electrical machines. These faults include eccentricity fault, rotor broken bar fault and short circuit fault. The impacts of these faults on the vibration signal of machines are surveyed. Analytical method based on air gap magnetic field in presence of different kind of fault is used to extract vibration signal. Finally, distinctive efficient methods for condition monitoring of large electrical machine using vibration signal is introduced and their competency are compared to each other.