Search results for " MOTOR"
showing 10 items of 1044 documents
Double squirrel cage induction motors: A new approach to detect rotor bar failures
2013
The purpose of this paper is to present a diagnosis technique, for rotor broken bar in double cage induction motor, 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. The validity of the proposed diagnosis approach is not limited to the analysis under steady-state operating conditions, but also for time-varying conditions where rotor fault components are spread in a wide frequency range.
Monitoring and Diagnosis of Failures in Squirrel-Cage Induction Motors Due to Cracked or Broken Bars
2011
In this paper three diagnostic procedures, based on on the vibration, current and instantaneous power monitoring for the detection and monitoring of incipient faults as cracks or bar breaks on squirrel cage motors are briefly reminded. The experimental investigations, carried out at the SDESLab (Sustainable Development Energy Savings Laboratory) of the University of Palermo in order to underline merits and drawbacks of the methods applied to the same die cast squirrel cage induction motor, are presented. The results of the investigations confirmed the effectiveness of the diagnostic procedures here considered.
Roku sīkās motorikas vingrinājumu un rotaļas izmantošana vārdu krājuma bagātināšanai vidējā pirmsskolas vecuma bērniem
2018
Bakalaura darba autore: Madara Zālīte Bakalaura darba nosaukums: Roku sīkās motorikas vingrinājumu un rotaļas izmantošana vārdu krājuma bagātināšanai vidējā pirmsskolas vecuma bērniem. Bakalaura darba mērķis: teorētiski un praktiski izpētīt vidējā pirmsskolas vecuma bērnu vārdu krājuma bagātināšanas iespējas roku sīkās motorikas vingrinājumos un rotaļās. Bakalaura darbs sastāv no 3 nodaļām – 2 teorētiskajām daļām un praktiskās daļas. Darba pirmajā nodaļā, autore apraksta valodas un runas vispārīgo raksturojumu. Pēta valodas un runas jēdzienu zinātniskajā literatūrā un 3 – 4 gadīgu bērnu pedagoģiski psiholoģisko raksturojumu problēmas skatījumā. Darba otrajā nodaļā tiek sniegts priekšstats p…
Effect of graphene nanoplatelets on the dielectric permittivity and segmental motions of electrospun poly(ethylene-co-vinyl alcohol) nanofibers
2021
The influence of the addition of graphene nanoplatelets (GNPs) on the intra/inter – molecular segmental motions of poly(ethylene-co-vinyl alcohol) (EVOH) was assessed by means of dielectric thermal analysis (DETA). The relaxation spectra were studied in terms of the dielectric permittivity (ε′) and the dielectric loss tangent (tan δ) at wide ranges of frequency (from 10−2 to 107 Hz) and temperature (from -150 to 140 °C). Two relaxation zones were disthinguished. Below the glass transition temperature (Tg), two β-relaxations were observed, which are characteristic local modes of mobility of the EVOH side groups, and related to the influence of the different surroundings of ethylene or vinyl …
Electrospun Poly(ethylene-co-vinyl alcohol)/Graphene Nanoplatelets Composites of Interest in Intelligent Food Packaging Applications
2018
Graphene nanoplatelets (GNPs) were synthetized from graphite powder and, thereafter, embedded in poly(ethylene-co-vinyl alcohol) (EVOH) fibers by electrospinning in the 0.1&ndash
Crosslinked chitosan/poly(vinyl alcohol)-based polyelectrolytes for proton exchange membranes
2019
[EN] The preparation polyelectrolytes based on crosslinked poly(vinyl alcohol) (PVA) and chitosan (CS) was considered as a feasible alternative to develop highly functionalised, cost-effective and eco-friendly membranes for proton exchange fuel cell technologies. CS/PVA-based membranes were combined with sulfosuccinic acid (SSA) as crosslinking and sulfonating agent, and glycerol (GL) to promote flexibility and favour their manageability. The chemical structure, the thermo-oxidative behaviour, the ethanol uptake, the electric, the proton conductivity, and the performance in direct ethanol fuel cell (DEFC) were assessed. In general, all the CS/PVA-based polyelectrolytes showed a synergetic i…
Functionalised poly (vinyl alcohol)/graphene oxide as polymer composite electrolyte membranes
2019
[EN] Crosslinked poly(vinyl alcohol) (PVA) based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells (DEFC). The membranes were functionalised by means of the addition of graphene oxide (GO) and sulfonated graphene oxide (SGO) and crosslinked with sulfosuccinic acid (SSA). The chemical structure was corroborated and suitable thermal properties were found. Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes, a significant reduction of the ethanol solution swelling and crossover was encountered, more relevant for those functionalised with SGO. In general, the composite membranes were stable under …
Modulation of cortical motor outputs by the symbolic meaning of visual stimuli
2010
The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is preceded b…
Evaluation of visual-motor reaction time and quality of response in rugby sevens players after the application of a neurocognitive training programme
2019
This work proposes a neurocognitive training (NCT) programme that seeks to optimise the mechanisms of visual perception, the processing of information and decision making. Also, to evaluate the eff...
Suppression of extinction with TMS in humans: from healthy controls to patients.
2006
We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …