Search results for "Rotating Machine"
showing 10 items of 13 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…
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…
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.
A knowledge-based master-model approach with application to rotating machinery design
2011
Novel rotating machinery design concepts and architectures are being explored to reduce mass, energy consumption, manufacturing costs, and environmental impact while increasing performance. As component manufacturers supply parts to original equipment manufacturers, it is desirable to design the components using a systems approach so that they are optimized for system-level performance. To accomplish that, suppliers must be able to model and predict the behavior of the whole machinery. Traditional computer-aided design/computer-aided engineering master-modeling approaches enable manual changes to be propagated to linked models. Novel knowledge-based master-modeling approaches enable automa…
HEALTH MONITORING, FAULT DETECTION AND DIAGNOSIS IN INDUSTRIAL ROTATING MACHINERY BY ADVANCED VIBRATION ANALYSIS
Control of hysteretic instability in rotating machinery by elastic suspension systems subject to dry and viscous friction
2010
Abstract Most of the undesired whirling motions of rotating machines can be efficiently reduced by supporting journal boxes elastically and controlling their movement by viscous dampers or by dry friction surfaces normal to the shaft axis, which rub against the frame. In the case of dry dampers, resonance ranges of the floating support configuration can be easily cut off by planning a motionless adhesive state of the friction surfaces. On the contrary, the dry friction contact must change automatically into sliding conditions when the fixed support resonances are to be feared. Moreover, the whirl amplitude can be restrained throughout the speed range by a proper choice of the suspension-to-…
Damping of rotor conical whirl by asymmetric dry friction suspension
2009
Abstract A new technique for the rotor whirl damping in rotating machinery, based on the elastic suspension of the journal boxes and the use of dry friction surfaces normal to the shaft axis between their supports and the frame, is here analysed theoretically for several cases of rotor systems characterized by mass and constraint asymmetry, where gyroscopic effects are to be expected and conical whirl motions may grow up. The critical flexural speeds can be easily cut off by an adhesive state of the supports and the whirl amplitude can be minimized as well throughout the remaining sliding range. Confining the operative angular speed of the rotor in the range of adhesive contact between the …
On the beneficial effect of rotor suspension anisotropy on viscous-dry hysteretic instability
2012
The destabilizing influence of the internal friction on the supercritical rotor whirl can be efficiently counterbalanced by other external dissipative sources and/or anisotropic suspension systems. The theoretical approach may take the internal dissipation into consideration either by dry or viscous models. Nevertheless, several numerical results and a new perturbation technique of the averaging type prove that similar rotor motions and stability limits are achievable by both models, whence the linear viscous assumption appears preferable. Thus, the internal hysteretic force may be expressed by the product of an equivalent viscous coefficient and the rotor centre velocity relative to a refe…
UiA Accelerated Life Time Bearing Test Rig – Test 1, 250 rpm
2020
Vibration data from an accelerated lifetime test of a bearing. Contains raw vibration data and shaft position data. The mean shaft speed is 250 rpm. Can be used for fault diagnosis and remaining useful lifetime estimation. Please see "00_ReadMe.pdf" file for more details. Update - 3 January 2022: This dataset is now updated to use floating point values for shaft position data, which gives a much more accurate description of the shaft position.
UiA Accelerated Life Time Bearing Test Rig – Test 3, Variable speed around 50rpm
2021
Vibration data from an accelerated lifetime test of a bearing. Contains raw vibration data and shaft position data. The mean shaft speed is 50rpm with a variation +- 40 rpm. Can be used for fault diagnosis and remaining useful lifetime estimation. Please see "00_ReadMe.pdf" file for more details.