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This research analyzes the vibration phenomenon in certain types of fractional slot permanent magnet synchronous machines that excites low order radial forces. The study utilizes a motor topology from the group having 12-stator slots and 10-rotor poles (12s10p) to identify and propose several design-based solutions to reduce vibration. Some electromagnetic design feature variations in the motor geometry...
The aim of the present paper is to diagnose the mechanical faults in induction motors. We have chosen this part in order to contribute to the diagnosis of electrical machines. The raising of stator current allows detecting the fatigue of the machine failure. The manner of the treatment decides the efficiency of the applied technique. We have examined the static eccentricity fault by a vibration signal...
This paper proposes, as a control scheme of a switched reluctance motor, back electromotive force control (back-EMF control for the abbreviation) in order to reduce the vibration and the acoustic noise of a switched reluctance motor. In back-EMF control, the winding current is kept around the current reference without switching the power devices in a corresponding phase in the drive circuit by utilizing...
In this work, vibration signals of a faulty induction motor are analyzed to establish an intelligent fault diagnosis system using Adaptive Neuro-Fuzzy Inference System (ANFIS). Firstly, signal spectra of individual motor fault models are obtained. Subsequently, representative characteristic frequency spectra are identified, and the correlation between the motor fault types and their corresponding...
In flywheel system, rotor is supported by mechanical bearing. In the cases that the weight of the rotor is heavy and the rotational speed is high, mechanical loss is large. Superconducting magnetic bearing (SMB) is introduced to support with contact-less and control-less. The rotor is supported by the pinning effect in SMB. Pinning force depends on the specification of the HTS. In this paper, the...
Eccentric mass unbalance of the electric motor causes vibration of the shaft and the whole system, when the rotational speed increases. This paper considers rotation about an estimated center of inertia for a bearingless motor to reduce the vibration and power consumption for magnetic suspension. A 12-slot/10-pole bearingless SPM motor is selected for the performance test, because it has low suspension...
Vibration analysis is one of the most successful techniques used for condition monitoring of rotating machines. Vibration analysis is a very efficient and convenient tool for diagnosing mechanical problems in induction motors. The aim of this paper is to show that vibration analysis is an efficient tool for diagnosing electromagnetic problems in induction motors, which are very specific for this type...
Vibrations of high speed SRM design focused on possible highest efficiency and low torque ripples both in motoring and generating mode of operation are investigated. The main constructional nodes that are source of vibrations are identified based on comparison of time sequences of motor frame displacement acceleration with total and phase motor current. Vibration analysis is the second stage of design...
In this paper, a method for fault detection of physical impairment of UAV rotor blades is presented. Actuators in multirotor UAV (Unmanned Aerial Vehicle) systems are common subjects fault diagnosis methods which are an essential part of the active fault-tolerant control scheme. Defects in a propulsion system of the aerial vehicle lead to the loss of thrust generated by rotors and as a result, to...
The development of Condition-Based Maintenance and Prognostics and Health Management systems can be fostered by models that accurately reproduce the effects and propagation of faults. Conventional methods applied to the analysis and simulation of rotor asymmetries in induction machines are based in the classical 2-D finite element approach, which is unable to reflect its complex effects, such as interbar...
Condition monitoring of electric machines is a procedure of increasing importance, as fault tolerant systems are becoming mandatory in many applications. Early diagnosis of faults is a basic pillar in order to achieve full tolerance by the maintenance of faulty parts in electrical machines. As far as electrical drives are concerned, the share of mechanical faults (imbalances, gears and bearings) is...
The analysis of the vibration response of electrical machines has importance in noise prediction and more recently, fault diagnosis. This work presents a strongly coupled 2-D magnetomechanical simulation of an induction machine under heavy operational conditions: a direct-on-line startup. Both healthy and broken bar states are simulated in a time span long enough to allow the detailed study of the...
The critical speed of the rotor can be calculated accurately by the transfer matrix method and the finite element method. Since the mass of the shaft section is neglected by the transfer matrix method, the calculation result is slightly larger. By establishing the 3D finite element model of the rotor system, the critical speed and mode of the rotor are analyzed. The results show that the bearing support...
In order to improve the output performance, multi-stator structure is applied to traveling wave type ultrasonic motor (TWUM). In this paper, taking into account the multi-stator traveling wave type ultrasonic motor (MSUM) with diameter of 60mm, authors apply the elastic contact principle to deduce the MSUM's simulation model. By reason of machining errors and installation errors, the stators and rotors...
The overall efficiency of a marine electrical power system is reliant on its condition monitoring algorithm. A competitive system has quick fault detection functionalities and maintenance enabled. This paper examines existing method to develop an online approach for superior detection of eccentricity fault in surface-mounted permanent magnet synchronous motors, in a marine propulsion setting. Detection...
Increasing levels of noise and vibration are early indicators for an evoluting error or defect on an electrical machine. There are many different approaches in monitoring the health of an electrical machine, e.g. noise-, vibration- or current-based methods. This paper investigates and compares different methods for noise analysis. Each method provides an own representation of the analysed signal....
In this paper, the natural vibration mode shapes and frequencies of the stator of large electric machine are computed by finite element method (FEM). In FEM model, several boundary treatments are especially considered, including welded connection between boards of stator, bolt connecting structure between end housing and frame board, shrink fitting between rotor axis and bearing. The influence of...
Mechanical seals are widely used in the rotation parts in various applications, and the failure of them may cause serious consequences, such as pollution, corrosion, equipment retirement, heavy casualties and other economic losses. The leakage rate of mechanical seal is mainly determined by the film thickness between rotor ring and stator ring. Moreover, the film thickness is one of the most important...
Infrared (IR) imaging for rotating machinery monitoring and fault diagnosis has gained noticeable attention in recent years since it enables non-contact, on-intrusive and singlesensor based temperature measurements. However, the IR image for fault identification requires the process of artificial feature extraction, which is influenced by personal experience. And the sensitivity of the infrared image...
Extracting weak features of incipient bearing fault from the collected vibration of rotating system is the basis of the fault diagnostics of main bearing in the aero engine. To monitor the running condition of the main bearing, a novel weak feature extraction method for bearing fault, named as iterative squared envelope analysis (ISEA) is proposed by extracting the fault characteristic orders of bearings...
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