Simulation of Energy Response Linearity, Resolution and e−/πe^-/\pi Ratio for the CASTOR Calorimeter at CMS

The response linearity, the energy resolution and the e^-/\pi ratio for the CMS CASTOR calorimeter is studied using gammas, electrons and pions in the energy range of 20 - 1000 GeV CASTOR is going to be installed at the very forward region of the CMS experiment

Ασφαλιστικά μέτρα στην ευρωπαϊκή έννομη τάξη (Κανονισμοί 1215/2012, 4/2009, 2019/1111)

Ασφαλιστικά μέτραProvisional, including protective, measure

A New Approach for Broken Rotor Bar Detection in Induction Motors Using Frequency Extraction in Stray Flux Signals

This paper offers a reliable solution to the detection of broken rotor bars in induction machines with a novel methodology, which is based on the fact that the fault-related harmonics will have oscillating amplitudes due to the speed ripple effect. The method consists of two main steps: Initially, a time-frequency transformation is used and the focus is given on the steady-state regime; thereupon, the fault-related frequencies are handled as periodical signals over time and the classical fast Fourier transform is used for the evaluation of their own spectral content. This leads to the discrimination of subcomponents related to the fault and to the evaluation of their amplitudes. The versatility of the proposed method relies on the fact that it reveals the aforementioned signatures to detect the fault, regardless of the spatial location of the broken rotor bars. Extensive finite element simulations on a 1.1 MW induction motor and experimental testing on a 1.1 kW induction motor lead to the conclusion that the method can be generalized on any type of induction motor independently from the size, power, number of poles, and rotor slot numbers

Breakdown Resistance Analysis of Traction Motor Winding Insulation under Thermal Ageing

Stator inter-turn faults are among the most important electric motor failures as they progress fast and lead to catastrophic motor breakdowns. Inter-turn faults are caused due to the windings’ insulation degradation. The main stress which deteriorates the insulation is the thermal one. Proper understanding of how this stress influences the electrical properties of insulation over time may lead to reliable prognosis and estimation of the motor’s remaining useful life. In transport applications where reliability and safety come first it is a critical issue. In this paper, extensive experimental testing and statistical analysis of thin film insulation for traction motor windings has been performed under fixed thermal stress. The results indicate that for high thermal stress the electrical properties of the insulation material present a non-monotonic behavior thus proving the well-known and established Arrhenius law inadequate for modelling this type of problems and estimating the remaining useful life of thin film insulation materials