0000000000260901
AUTHOR
Claudio Rossi
Closed-loop bandwidth impact on MVSA for rotor broken bar diagnosis in IRFOC double squirrel cage induction motor drives
This paper investigates the detectability of rotor broken bars in indirect rotor flux oriented control (IRFOC) for variable speed double cage induction motor drives, using vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of rotor asymmetries in the machine is based on the signature analysis of electrical or mechanical variables. Therefore, the investigation of rotor fault components for different bandwidths of closed-loop regulators is necessary to evaluate its relevance in the above listed variables. This paper investigates the impact of the control system on relevance of the fault components computed from axial an…
Isotopic Effect on the Kinetics of the Belousov-Zhabotinsky Reaction
In this work we present results about the deuterium isotope effect on the global kinetics of a Belousov-Zhabotinsky reaction in batch conditions. A nonlinear dependence of the Induction Period upon the percentage of deuterated reactants was found. The isotopic effect on the bromination reaction of malonic acid was evaluated.
Indagini preliminari ToF-SIMS su manufatti lignei provenienti dal museo diocesano di Palermo
The Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a methodology only recently applied to the study of the artworks. This tecnique allow the acquisition of a high amount of morphological and chemical information, directly related to the surface properties of the investigated sample. Through this technique it is possible to carry out an elemental analysis of the material as well as a determination of molecular ions (organic and/or inorganic) with a molecular weight ≤ 5000 Dalton (atomic mass unit). Moreover it is possible to use this spectrometry in an Imaging mode, that supplies a spatial distribution of the present substances, by the generation of "a chemical image", with a v…
Investigation of motor current signature and vibration analysis for diagnosing rotor broken bars in double cage induction motors
This paper investigates the detectability of rotor broken bars in double cage induction motors using current signature and vibration analysis techniques. Double cage induction motors are commonly used for applications where successive loaded starts-up are mandatory. Experimental results were performed under healthy and faulty cases, and for different load conditions using each technique. Rotor broken bars fault detection based on sideband current components may fails due to the presence of inter bar currents that reduce the degree of rotor asymmetry, yielding to a decrease of the magnitude of these spectral components. But inter bar currents produce core vibrations in the axial direction, w…
Inhibition of Fcγ Receptors in the Plasma of Subjects with Down's Syndrome
Abstract Subjects with Down's syndrome have several immunological abnormalities. We examined the sera of 29 subjects with Down's syndrome for the presence of Fcγ receptor blocking and for the presence of anti-ssDNA antibodies by EA rosette inhibition. Fifty-five percent of Down subjects had levels of inhibition above the upper limit of normality in comparison to 7% of normal controls. The finding that after polyethylene glycol precipitation of selected sera giving high levels of EA rosette inhibition there was a reduction or a disappearance of the EA rosette inhibition could indicate that the blocking factors detected behaved as immune complexes. Since almost all subjects with anti-ssDNA an…
Quantitative Rotor Broken Bar Evaluation in Double Squirrel Cage Induction Machines under Dynamic Operating Conditions
Advanced monitoring techniques leading to fault diagnosis and prediction of induction machine faults, operating under non-stationary conditions have gained strength because of its considerable influence on the operational continuation of many industrial processes. In case of rotor broken bars, fault detection based on sideband components issued from currents, flux, instantaneous control or power signals under different load conditions, may fail due to the presence of inter-bar currents that reduce the degree of rotor asymmetry, especially for double squirrel cage induction motors. But the produced core vibrations in the axial direction, can be investigated to overcome the limitation of the …
Vibration signature analysis for rotor broken bar diagnosis in double cage induction motor drives
The paper investigates the diagnosis of rotor broken bars in field oriented controlled (FOC) double cage induction motor drives, using current and vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of asymmetries in the machine are based on the signature analysis of electrical variables. The proposed diagnosis approach is based on optimized use of wavelet analysis by a pre-processing of phase current or axial/radial vibration signals. Thus, the time evolution of the tracked rotor fault components can be effectively analyzed. This paper shows also the relevance of the fault components computed from axial vibration sign…
Burkitt’s lymphoma in pregnant woman: Difficult management of a rare case
Highlights • Burkitt’s lymphoma, an aggressive non-Hodgkin lymphoma, is extremely rare during pregnancy. • Lymphoma of the small intestine is often overlooked in the early stages of the disease. • We described a multidisciplinary approach, cesarean section with surgical intestinal exploration.
Vibration signature analysis for monitoring rotor broken bar in double squirrel cage induction motors based on wavelet analysis
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…