Electrical machines are important devices that convert electric energy into mechanical work and are widely used in industry and people’s life. Undesired vibrations are harmful to their safe operation. Reviews from the viewpoint of fault diagnosis have been conducted, while summaries from the perspective of dynamics is rare. This review provides systematic research outlines of this field, which can help a majority of scholars grasp the ongoing progress and conduct further investigations. This review mainly generalizes publications in the past decades about the dynamics and vibration of electrical machines. First the sources of electromagnetic vibration in electrical machines are presented, which include mechanical and electromagnetic factors. Different types of air gap eccentricity are introduced and modeled. The analytical methods and numerical methods for calculating the electromagnetic force are summarized and explained in detail. The exact subdomain analysis, magnetic equivalent circuit, Maxwell stress tensor, winding function approach, conformal mapping method, virtual work principle and finite element analysis are presented. The effects of magnetic saturation, slot and pole combination and load are discussed. Then typical characteristics of electromagnetic vibration are illustrated. Finally, the experimental studies are summarized and the authors give their thoughts about the research trends.

https://www.mdpi.com/1996-1073/11/7/1779/pdf

Review of Electromagnetic Vibration in Electrical Machines

This paper investigates the vertical dynamic behavior of railway tracks with monoblock sleepers. Whole- and half-track finite element (FE) models are presented in which the rails and sleepers are r...

An investigation into the vertical dynamics of tracks with monoblock sleepers with a 3D finite-element model

Switched reluctance motors are well suited to in-wheel-motor-driven electric vehicles because of their numerous advantages, such as a high torque density, a high operating efficiency and excellent power–speed characteristics However, these advantages are overshadowed by their inherent high torque ripple and vibrations The unbalanced radial force of the switched reluctance motor is one of the main reasons for vibrations of the switched reluctance motor but has attracted less attention for in-wheel motor applications according to previous research In this paper, the vertical component of the residual unbalanced radial force of the switched reluctance motor, ie the vertical force of the switched reluctance motor, is taken into account in the stability and comfort analysis for in-wheel-motor-driven electric vehicles The results in this paper indicate that the vertical force of the switched reluctance motor has a great effect on the lateral and anti-rollover stabilities of the vehicle The direct cause of this phenomenon is that the vertical force of the switched reluctance motor is directly applied on the wheels, which will result in a significant variation in the tire load, and the tire can easily jump off the ground Furthermore, the frequency of the vertical force of the switched reluctance motor covers a wide bandwidth which involves the resonance frequencies of the vehicle body’s vibrations and the wheel bounce As a result, the comfort of the vehicle is greatly harmed Therefore, the effect of the vertical force of the switched reluctance motor on the comfort of the vehicle is also considerable in some resonance situations The conclusion is that the vertical force of the switched reluctance motor not only causes the stability of the vehicle to deteriorate but also has a considerable effect on the comfort of the vehicle, and an appropriate control method for the switched reluctance motor is desired

Effect of the unbalanced vertical force of a switched reluctance motor on the stability and the comfort of an in-wheel motor electric vehicle

The vibrations developed during the work represent one of the main mechanical problems of the electric motors. Their frequencies and levels can cause large damages of different electrical motors parts. This is the reason why even in the design phase it is useful to be known the values of the natural frequencies of the parts. This can be made in two different ways: using modern capabilities of finite element method (FEM) or doing experimental modal analysis. The study developed in the present paper refers to the modal analysis of a three-phase squirrel cage induction of 1.5 kW, for both, for its elements and, for motor and the electric motor as an assembly. The FEM modal analysis was applied using ABAQUS software for assembly of the 7 elements of the motor. The 3D model was developed, mechanical connections being of screw type. The theoretical model was validated by experiments, with impact hammer test method. The validation confirms the assumptions made for the 3D model and the designed model can be use, as example, for other FEM based modal analysis. The natural frequencies obtained both by FEM and experimental method does not overlap on the working frequencies.

Three-phase squirrel-cage induction motor modal analyses. Theoretical and experimental aspects

The study on the position-dependent dynamic characteristics of a vertical ball screw feed system without counterweight is an important step in the enhancement of the structural performance of mini-...

Effect of the screw–nut joint stiffness on the position-dependent dynamics of a vertical ball screw feed system without counterweight

Development of a finite element solution module for the analysis of the dynamic behavior and balancing effects of an induction motor system

In a high-speed gas spindle, the drawbar force required to hold the drill bit is produced by the deformation of disc spring stacks. This drawbar force, applied to the collet—spindle interface, generates a contact pressure on the collet to hold the drill bit in position. Thus, the behaviour of the collet—spindle interface is critical to machining quality. Accordingly, this study investigated how disc spring characteristics affect the collet—spindle interface in a high-speed spindle. Typi-cally, the drawbar force will decrease following the deformation of disc springs resulting from the effects of centrifugal force at high rotational speeds. This effect must be considered, especially in high-speed spindle applications. This study first measured the drawbar force experimentally and compared these results with theoretical and finite-element analysis (FEA) data under static conditions (i.e. no rotation). Having obtained satisfactory agreement among these data, the FEA was extended to a further investig...

Dynamic analysis of disc spring effects on the contact pressure of the collet—spindle interface in a high-speed spindle system

A systematic approach for analysing vibration-related problems of electrical machines, integrating both complex electromagnetic and rotordynamic analyses, is completely presented with an in...

Y D Cheng

Papers

Development of a finite element solution module for the analysis of the dynamic behavior and balancing effects of an induction motor system

Dynamic analysis of disc spring effects on the contact pressure of the collet—spindle interface in a high-speed spindle system

Electromagnetic—rotordynamic integrated vibration analysis for electrical machines