Search results for " Rotating machines"

showing 4 items of 4 documents

Vibration signature analysis for monitoring rotor broken bar in double squirrel cage induction motors based on wavelet analysis

2014

Purpose – The purpose of this paper is to present a diagnosis technique, for rotor broken bar in double cage induction motor, based on advanced use of wavelet transform analysis. The proposed technique is experimentally validated. Design/methodology/approach – The proposed approach is based on a combined use of frequency sliding and wavelet transform analysis, to isolate the contribution of the rotor fault components issued from vibration signals in a single frequency band. Findings – The proposed technique is reliable for tracking the rotor fault components over time-frequency domain. The quantitative analysis results based on this technique are the proof of its robustness. Research limit…

EngineeringFrequency bandElectrical machines Fault analysis Condition monitoring Fourier transforms Rotating machines RotorsSettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciWaveletControl theoryRobustness (computer science)Electrical machineRotorComputational Theory and MathematicElectrical and Electronic EngineeringPractical implicationsVibration signaturebusiness.industrySquirrel-cage rotorApplied MathematicsComputer Science Applications1707 Computer Vision and Pattern RecognitionComputer Science ApplicationsCondition monitoringVibrationComputational Theory and MathematicsFault analysiFourier transformRotating machinebusinessInduction motor
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A portable instrument for the location and identification of defects generating PD

2011

A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…

EngineeringPartial Discharges; Insulation Systems; Rotating Machines; DiagnosticsRotating Machinebusiness.industryStatorAcousticsLow-pass filterPartial DischargesBandwidth (signal processing)Electrical engineeringCurrent transformerlaw.inventionInsulation SystemsInsulation SystemSettore ING-IND/31 - ElettrotecnicaRotating MachinesElectromagnetic coillawPartial dischargePartial DischargeHigh-pass filterbusinessDiagnosticsDiagnostics FPGA Partial Discharges SensorsVoltage reference
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A Model-Based Control Strategy for Wind Turbines with Asynchronous Generator

2007

In this paper a model based control methodology is described with reference to a wind turbine for production of alternative energy. The mathematical model of a 600 kW wind turbine is taken into account assuming a well defined profile of the rotor blades. A set of reference angular speeds of the asynchronous generator and a set of reference pitch angles of the blade wind turbine are obtained in order to maximize the extracted wind power and to reach equilibrium conditions between the wind-generated torque and the electric torque of the generator. Finally a PID model based controller is designed and then tested by means of simulation experiments.

EngineeringWind powerbusiness.industryRotor (electric)Induction generatorPID controllerTurbinelaw.inventionPhysics::Fluid DynamicsElectricity generationSettore ING-INF/04 - AutomaticaControl theorylawWind power generation Asynchronous rotating machines Gain scheduling control PID control.Physics::Space PhysicsTorquebusinessPhysics::Atmospheric and Oceanic PhysicsGenerator (mathematics)2007 International Conference on Clean Electrical Power
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Non-Linear Hysteretic Instability in Rotating Machinery

2013

The destabilizing influence of the shaft hysteresis on the supercritical whirl of rotating machines can be efficiently counterbalanced by proper external dissipative sources in the supports and/or anisotropic suspension systems. The hysteretic effect may be treated either by dry or viscous models obtaining different but somehow similar results in the hypothesis of small dissipation levels. Thus the linear viscous assumption is often accepted as a crude approximation for a straightforward analysis of the whirling instability. Nevertheless the internal friction should be regarded most likely as non-linear and could be approximated for example by Coulombian models taking thus into account also the releasing effect of some shrink-fit coupling present in the mechanical assembly.
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