1,721,025 research outputs found
Introduction
No full text- Introduction to J.O. Frosini, L. Pegoraro, The Italian Constitution. Text and Note
How to define and control the significant environmental and energy aspects of combined-cycle energy production utilities
No full textMonitoring and diagnostics of electrical machines and drives: A state of the art
No full textDue to the increasing spread of electrical machines and drives in any field and to the growing development of researches on their predictive maintenance, a novel review of the literature on the diagnostics of these devices may be useful for future references. The aim of this paper is to show an up-to-date overview of the investigated techniques, by subdividing them with respect to the components most prone to fault, with the aim to cover all the main types of machines, from the low voltage motors to the large power generators. Particular attention will be paid on the methodologies based on the electromagnetic signals
Indagine sulla soddisfazione dei clienti e benchmarking: due strumenti della qualità totale
No full textPerformance improvement of SPM synchronous machines with non-conventional stator slot magnetic wedges
No full textThe opportunity to employ magnetic wedges in superficial permanent magnet machines with fractional-slot concentrated winding has been evaluated in this paper, with the aim to reduce the power losses, especially in the magnets, to increase the overall efficiency and to improve the field weakening capability. Finite element simulations with two different software are here presented, by using a model experimentally validated on a real motor. A novel wedge composed by different portions of materials with different values of magnetic permeability is proposed. The effects of both conventional and nonconventional magnetic wedges have been evaluated, in order to optimize the performance of the motor in all working conditions
Analysis and design of innovative magnetic wedges for high efficiency permanent magnet synchronous machines
Full text linkThe global decarbonization targets require increasingly higher levels of efficiency from the designers of electrical machines. In this context, the opportunity to employ magnetic or semi-magnetic wedges in surface-mounted permanent magnet machines with fractional-slot concentrated winding has been evaluated in this paper, with the aim to reduce the power losses, especially in the magnets. Since an analytical calculation is not sufficient for this evaluation, finite element methods with two different software have been employed, by using a model experimentally validated on a real motor. The effects of wedges with different values of permeability and different magnetization characteristics have been evaluated on flux density, back electromotive force, and inductances, in order to choose the more suitable wedge for the considered motor. Furthermore, a new wedge consisting of different portions of materials with different magnetic permeability values is proposed. The effects of both conventional and unconventional magnetic wedges were assessed to optimize the motor performance in all working conditions
Modeling of hydrodynamics and mechanical aspects of a Wave Energy Converter (WEC) to understand the main principles
No full textThis work aims at illustrating a first-approach modeling of an all-purpose wave energy converter (WEC), and reproducing its allegedly behavior, once there is a need to forecast its production from a location, where all the monitoring data are available, to another location. A few commercial software provide such a feature but, to proficiently use them, several practical parameters are needed and this makes the learning quite hard. In the proposed model, some parameters are offered and can be tuned according with the device to reproduce, and its known data (e.g. power matrix). The Simulink/Matlab model needs the couple (H,T) (wave height and period) as input, and it provides mechanic, and then, electric power as output: using a time series of (H i ,T i ), it is able to produce a suitable power profile, useful to be used-for instance-in feasibility studies
Transfer Learning Technique for Automatic Bearing Fault Diagnosis in Induction Motors
No full textIn this paper, the transfer learning technique is used to modify two already trained Convolutional Neural Networks for bearing fault recognition. In particular, the transfer learning technique is used to transfer the acquired knowledge of the neural networks, a model of the AlexNet and "CommandNet", previously trained for image and speech recognition, to the particular case of the bearing fault recognition in induction motors. The transfer learning will substitute just the final layers of the Deep Neural Networks classifier, and requires for a complete re-training operation only few data in comparison to big training datasets required for a complete training from scratch. In this contribution vibration signals from two different sensors and datasets are used to generate the spectrograms to feed the networks
The assessment and management of environmental and energy aspects related to industrial plants
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