Electrical Signature Analysis (ESA) is the method of using the electric machine magnetic field as the transducer as measured through voltage and current. The method was originally developed by Oak Ridge National Labs in the late 1980s for the expressed purpose of fault detection of gear and bearing wear in driven equipment in addition to the electric machine. This article discusses the use of expert system ESA of wind generators and powertrain with a focus on DFIG (Doubly-Fed Induction Generators) although ESA has been successful in all platform types. The paper identifies the approach for stator, rotor, brush and inverter, bearings, coupling, gearbox, main bearing and blade analysis as an introduction. The technology discussed has been applied for detecting faults from immediate to at least 14 months before failure and has been used for trending. The type of ESA discussed involves the evaluation of voltage, current, kilowatt and airgap torque spectra with voltage and current in -dB, power in kilowatts, and airgap torque in lb-ft or newtons. For the purposes of this paper we will focus on just voltage and current data and spectra.
ET_Penrose_FL24_FlowTHREE