Search results for "Axia"

Test bench for coupling and shielding magnetic field

2016

This paper describes a test bench for training purposes, which uses a magnetic field generator to couple this magnetic field to a victim circuit. It can be very useful to test for magnetic susceptibility as well. The magnetic field generator consists of a board, which generates a variable current that flows into a printed circuit board with spiral tracks (noise generator). The victim circuit consists of a coaxial cable concentric with the spiral tracks and its generated magnetic field. The coaxial cable is part of a circuit which conducts a signal produced by a signal generator and a resistive load. In the paper three cases are studied. First, the transmitted signal from the signal generato…

A new approach to the design of a speed-torque-controlled rubber V-belt variator

2005

This paper presents a new model for a torque-speed-sensing rubber V-belt variator. The actuators are of the centrifugal roller kind on the driver side and a helical torque cam plus a compression-torsion spring on the driven side. The equations permit designing the actuator geometry in order to keep the transmissible torque as close as possible to the torque request in the whole operative field. Moreover, a procedure is suggested for the most proper design of an automatic variator of this kind. It permits choosing the required variogram of the transmission, i.e. the matching between the engine and the transmission, and designing the actuators: roller mass, housing shape, contact plate angle…

Vibration signature analysis for rotor broken bar diagnosis in double cage induction motor drives

2013

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…

Efficient FDTD analysis of discontinuities in a square coaxial waveguide

1996

Covariance between components of biaxial stress state in fatigue life calculations

1992

In this paper influence of correlalions between components of random stress tensor on the calculated fatigue life of the machine element has been analysed. Two groups of covariance matrices for components of biaxial stress state were considered. The first group was arbitrarily assumed and the second one was determined on the basis of the measured strains in the element of the vibrating screen for aggregate. Computer simulation was realized with four criteria of multiaxial random fatigue. Cycles were counted with the method of rain flow and damages were cumulated according to Palmgren-Miner hypothesis. It has been shown that covariances between components of stress state tensor strongly infl…

Load-carrying capacity of axially-loaded RC members with circular openings

2012

Abstract Core drilling is today one of the most used technique among the group of partially destructive testing methods in reinforced concrete (RC) members. Even if the engineering practice provided to extract cores only in beams, taking samples from columns could be often necessary. In this case, the presence of the hole introduced a geometrical discontinuity in the member, creating a disturbed region. Consequently, compressive stresses will disperse in lateral direction as they have to avoid the drilled area. A bursting tensile force will develop, in orthogonal direction to the column axis, and if no sufficient reinforcement was arranged, a vertical crack will form, leading to the concret…

Dimensionless analysis of RC rectangular sections under axial load and biaxial bending

2012

This paper proposes a numerical procedure able to provide ultimate curvature and moment domains of rectangular RC sections subjected to combined axial load and biaxial bending. The formulation is carried out in dimensionless terms in order to give results that are valid for classes of sections characterized by the same values of the geometric and mechanical parameters governing the section response. The role of some of these parameters is investigated here. The results show possible correlations linking the actual values of moment and curvature to the values corresponding to two cases of uniaxial bending to be considered separately. © 2012 Elsevier Ltd.

A Simple Model for the Axial Thrust in V-Belt Drives

1996

Simple formulas can relate axial thrust and torque of rubber V-belt drives, taking into consideration the radial penetration of the belt.

A Novel Approach to the Characterization and Modelig of Microwave Transistor Packages

1994

A novel approach to the characterization and modeling of microwave transistor packages through dedicated VNA measurements is presented. By combining a multi-step partitioning method with the use of purposely realized - but technologically simple - "package style" test devices, the proposed technique permits to derive in a systematic manner an equivalent circuit for both the transistor package and the test-fixture mount employed for the characterization. Since it does not rely on the indirect, optimization-based, conventional extraction methods of the literature, nor on a simplified circuit structure for the overall parasitic fourport embedding the active device, it is able to provide a high…

Diagnosis of mechanical unbalance for double cage induction motor load in time-varying conditions based on motor vibration signature analysis

2013

This paper investigates the detectability of mechanical unbalance in double cage induction motor load using motor vibration signature analysis technique. Rotor imbalances induce specific harmonic components in electrical, electromagnetical, and mechanical quantities. Harmonic components characteristic of this category of rotor faults, issued from vibration signals analysis, are closely related to rotating speed of the rotor, which complicates its detection under non-stationary operating conditions of the motor. Firstly, experimental results were performed first under healthy and mechanical load unbalance cases, for different load levels under steady-state operating conditions to evaluate th…