646 Vibration suppression of rotor systems using repulsive magnetic bearing and automatic ball balancer

2008 ◽  
Vol 2008 (0) ◽  
pp. _646-1_-_646-6_
Author(s):  
Tsuyoshi INOUE ◽  
Hideaki NIIMI ◽  
Yukio ISHIDA
Keyword(s):  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Rotor Systems

Modelling, Analysis and Identification of the Parallel and Angular Misalignments in a Coupled Rotor-Bearing-AMB System

2020 ◽  
Author(s):  
Siva Srinivas R ◽  
Rajiv Tiwari ◽  
Ch. Kanna Babu
Keyword(s):  
Mathematical Model ◽  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Identification Algorithm ◽  
Rotor Systems ◽  
Force Moment ◽  
Coupling Force ◽  
Auxiliary Bearing ◽  
Amb System

Abstract The standard techniques used to detect the misalignment in rotor systems are loopy orbits, multiple harmonics with predominant 2X component, and high axial vibration. This paper develops a new approach for the identification of misalignment in coupled rotor systems modelled using 2-node Timoshenko beam finite elements. The coupling connecting the turbine and generator rotor systems is modelled by a stiffness matrix, which has both static and additive components. While the magnitude of static stiffness component is fixed during operation, the time varying additive stiffness component displays a multi-harmonic behaviour and exists only in the presence of misalignment. To numerically simulate the multi-harmonic nature coupling force/moment as observed in experiments, a pulse wave is used as the steering function in the mathematical model of the additive coupling stiffness (ACS). The representative TG system has two-rotor systems, each having two discs and supported on two flexible bearings - connected by coupling. An active magnetic bearing (AMB) is used as an auxiliary bearing on each rotor for the purposes of vibration suppression and fault identification. The formulation of mathematical model is followed by the development of an identification algorithm based on the model developed, which is an inverse problem. Least-squares linear regression technique is used to identify the unbalances, bearing dynamic parameters, AMB constants and importantly the coupling static and additive stiffness coefficients. The sensitivity of the identification algorithm to signal noise and bias errors in modelling parameters have been tested. The novelty of paper is the representation and identification of misalignment using the ACS matrix coefficients, which are direct indicators of both type and severity of the misalignment.

Suppression of Persistent Rotor Vibrations Using Adaptive Techniques

2003 ◽  
Author(s):  
Alex L. Matras ◽  
George T. Flowers ◽  
Robert Fuentes ◽  
Mark Balas ◽  
Jerry Fausz
Keyword(s):  
Large Scale ◽  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Structural Systems ◽  
Running Speed ◽  
Rotor Systems ◽  
Adaptive Techniques ◽  
Disturbance Rejection Control ◽  
Persistent Disturbances

Recent work in the area of adaptive control has seen the development of techniques for the adaptive rejection of persistent disturbances for structural systems. They have been implemented and tested for large-scale structural systems, with promising results, but have not been widely applied to smallerscale systems and devices. Rotor systems are subject to a variety of persistent disturbances (for example, due to mass imbalance, blade-pass effects) that occur at the rotor running speed or multiples of the running speed. The frequencies of such disturbance forces are generally known, but their magnitudes tend to vary over time. Adaptive techniques to counter the effects of such disturbances would appear to be a promising strategy in this regard. In order to assess the effectiveness of adaptive disturbances rejection for rotor applications and identify issues associated with implementation, and adaptive disturbance rejection control is developed, implemented, and tested for a magnetic-bearing-supported rotor system. Some conclusions and insights concerning the application of this method to rotor system vibration suppression are presented and discussed.

Suppression of Persistent Rotor Vibrations Using Adaptive Techniques

2006 ◽  
Vol 128 (6) ◽  
pp. 682-689 ◽  
Author(s):  
Alex L. Matras ◽  
George T. Flowers ◽  
Robert Fuentes ◽  
Mark Balas ◽  
Jerry Fausz
Keyword(s):  
Disturbance Rejection ◽  
Large Scale ◽  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Structural Systems ◽  
Running Speed ◽  
Rotor Systems ◽  
Adaptive Techniques ◽  
Persistent Disturbances

Recent work in the area of adaptive control has seen the development of techniques for the adaptive rejection of persistent disturbances for structural systems. They have been implemented and tested for large-scale structural systems, with promising results, but have not been widely applied to smaller-scale systems and devices. Rotor systems are subject to a variety of persistent disturbances (for example, due to mass imbalance, blade-pass effects) that occur at the rotor running speed or multiples of the running speed. The frequencies of such disturbance forces are generally known, but their magnitudes tend to vary over time. Adaptive techniques to counter the effects of such disturbances would appear to be a promising strategy in this regard. In order to assess the effectiveness of adaptive disturbance rejection for rotor applications and identify issues associated with implementation, an adaptive disturbance rejection control is developed, implemented, and tested for a magnetic-bearing-supported rotor system. Some conclusions and insights concerning the application of this method to rotor system vibration suppression are presented and discussed.

Optimization of Bearing Locations for Rotor Systems With Magnetic Bearings

1995 ◽  
Author(s):  
Sriram Srinivasan ◽  
Eric H. Maslen ◽  
Lloyd E. Barrett
Keyword(s):  
Design Process ◽  
Magnetic Bearing ◽  
Rotating Machinery ◽  
Rotor Systems ◽  
Infinity Norm ◽  
Multi Stage ◽  
Scalar Measure ◽  
Bearing Design ◽  
The Stability ◽  
Practical Measure

This paper presents a method for quickly evaluating the effect of changes in bearing location on bearing design for stability of rotating machinery. This method is intended for use by rotating machinery designers to select the “best” bearing locations prior to the bearing design process. The purpose of the method is to improve the design process by separating the problem of determining the “best” bearing locations from that of determining the actual bearing design. The method is independent of the type of bearing employed. For each candidate bearing configuration, the method provides a scalar measure of the relative ability of bearings to meet stability specifications. Within certain limits, the stability specifications are defined by the designer. The scalar measure is used to rank the candidate bearing locations and thereby select the best one. The scalar measure is compared to a practical measure of magnetic bearing design such as the infinity norm of the controller for an example design of a multi-stage centrifugal compressor.

scholarly journals Magnetic Bearing Proposal Design for a General Unbalanced Rotor System enhanced because of using sensors/actuators based in nanostructures

2019 ◽  
Vol 95 ◽  
pp. 01002
Author(s):  
Jesus A. Calderón ◽  
Eliseo B. Barriga ◽  
Roland Mas ◽  
Luis Chirinos ◽  
Enrique Barrantes ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Conveyor Belt ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Uniform Rotation ◽  
Identification Process ◽  
Rotor Systems ◽  
Rotational Movement ◽  
Unbalanced Rotor

Rotor systems need bearings in order to keep uniformity of rotational movement transmission. However, bearingsgenerate friction and energy losses due to heating transmisssion through the friction; for this reason, mechanicak bearings are replaced by magnetic bearings owing to avoid energy losing because of friction. We designed Active Magnetic Bearings (AMB) to transmit rotational movement from source of movement (motor) through the rotor to the movement receptor (such as a conveyor belt). Magnetic Bearings need accuracy during System Identification process and a sophisticated control algorithm to get an uniform rotation movement transmission. In this work also it was analyzed and proved by simulations that Active Magnetic Bearings composed with sensors /actuators based in nanostructures are faster and robust compared with AMB based in traditional sensors/actuators. It because, nanostructures receive and send signals better way tan traditional sensors/actuators, because of high oredered nanoarrays improve sensor/actuator properties.

Stability of magnetic bearing rotor systems and the effects of gravity and damping

AIAA Journal ◽  
1994 ◽  
Vol 32 (7) ◽  
pp. 1492-1499 ◽  
Author(s):  
P. Zhong ◽  
M. A. Townsend
Keyword(s):  
Magnetic Bearing ◽  
Rotor Systems

Optimization of Bearing Locations for Rotor Systems With Magnetic Bearings

1997 ◽  
Vol 119 (2) ◽  
pp. 464-468 ◽  
Author(s):  
S. Srinivasan ◽  
E. H. Maslen ◽  
L. E. Barrett
Keyword(s):  
Design Process ◽  
Magnetic Bearing ◽  
Rotating Machinery ◽  
Rotor Systems ◽  
Infinity Norm ◽  
Scalar Measure ◽  
Bearing Design ◽  
The Stability ◽  
Multistage Centrifugal Compressor ◽  
Practical Measure

This paper presents a method for quickly evaluating the effect of changes in bearing location on bearing design for stability of rotating machinery. This method is intended for use by rotating machinery designers to select the “best” bearing locations prior to the bearing design process. The purpose of the method is to improve the design process by separating the problem of determining the “best” bearing locations from that of determining the actual bearing design. The method is independent of the type of bearing employed. For each candidate bearing configuration, the method provides a scalar measure of the relative ability of bearings to meet stability specifications. Within certain limits, the stability specifications are defined by the designer. The scalar measure is used to rank the candidate bearing locations and thereby select the best one. The scalar measure is compared to a practical measure of magnetic bearing design such as the infinity norm of the controller for an example design of a multistage centrifugal compressor.

Vibration Analysis of a Self-Excited Vibration in a Rotor System Caused by a Ball Balancer

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Yukiko Ishida ◽  
Hideaki Niimi
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Vibration Suppression ◽  
The Self ◽  
Rotor Systems ◽  
Excited Vibration ◽  
Amplitude Vibration ◽  
Speed Range ◽  
Large Amplitude Vibration ◽  
Fundamental Equations

The ball balancer has been used as a vibration suppression device in rotor systems. It has a superior characteristic that the vibration amplitude is reduced to zero theoretically at a rotational speed range higher than the critical speed. However, the ball balancer causes a self-excited vibration near the critical speed when the balls rotate in the balancer. This self-excited vibration may occur in the wide rotational speed range with a large amplitude vibration, and in such a case, escaping from it becomes difficult. In this paper, the occurrence region and the vibration characteristics of the self-excited vibration caused by the ball balancer are investigated. The nonlinear theoretical analysis is performed and a set of the fundamental equations governing the self-excited vibration is obtained. The influences of the parameters of the ball balancer, such as, the damping of the ball’s motion, the ball’s mass, and radius of the balls’ path, are explained and they are also validated experimentally.

A Design Technique for a Magnetic Bearing-Rotor in a Turbo Blower Considering Critical Speeds

2012 ◽  
Vol 569 ◽  
pp. 564-567
Author(s):  
Hoon Hyung Jung ◽  
Seung Hee Kang ◽  
Bang Hyun Cho ◽  
Chae Sil Kim
Keyword(s):  
Element Model ◽  
Magnetic Bearing ◽  
Design Technique ◽  
Loop Control ◽  
Critical Speeds ◽  
Rotor Systems ◽  
Turbo Blower ◽  
Bearing Stiffness ◽  
Control Forces ◽  
Stiffness And Damping

This paper introduces a rotor design technique for a turbo blower supported by magnetic bearings that considers the critical speeds of the rotor. An important factor for rotor critical speeds is the stiffness of its bearings. The magnetic bearing acts as a negative spring, called the position stiffness prior to operation, and rotor systems are initially unstable until the stiffness (current stiffness) and damping in the active control rotating system are determined using closed loop control forces. This paper describes a finite element model for the rotor, derives the stiffness equations for the magnetic bearing, and defines the total magnetic bearing stiffness including the position stiffness and current stiffness. Finally, the magnetic bearing stiffness that avoids the rotor critical speeds is chosen.

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