VIBRATION INDUCED FAILURE ANALYSIS OF A HIGH SPEED ROTOR SUPPORTED BY ACTIVE MAGNETIC BEARINGS

2015 ◽  
Vol 39 (4) ◽  
pp. 855-866 ◽  
Author(s):  
Sarvat M. Ahmad ◽  
Osman A. Ahmed ◽  
Zaharuddin Mohamed
Keyword(s):  
Fault Diagnosis ◽  
High Speed ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Flexible Rotor ◽  
Describing Function ◽  
Industrial Grade ◽  
Sinusoidal Input ◽  
Diagnosis Algorithm ◽  
Amb System

Active Magnetic Bearings (AMBs) are increasingly used in various industries and a quick re-levitation of AMBs supported high speed flexible rotor is necessary in case of vibration induced failure. A robust fault diagnosis algorithm is presented to detect suspected saturation type of nonlinearity associated with a power amplifier. A five degree-of-freedom AMB system consisting of four opposing pair of radial magnets and a pair of axial magnets is considered. In this paper failure of an industrial grade AMB system is investigated using Sinusoidal Input Describing Function (SIDF) method. SIDF predicts the gain and frequency at which failure occurs. It is demonstrated that the predicted frequency is in agreement with the frequency at which failure occurs.

Modeling, Motion and Vibration Control for Flexible Rotor Supported by Active Magnetic Bearings

2005 ◽  
Author(s):  
Yuichi Nakajima ◽  
Takahito Sagane ◽  
Hiroshi Tajima ◽  
Toru Watanabe ◽  
Kazuto Seto
Keyword(s):  
High Speed ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Flexible Rotor ◽  
Bending Vibration ◽  
Modeling And Control ◽  
Control Approach ◽  
Flexible Rotors ◽  
Pass Through ◽  
And Control

This paper proposes a new modeling technique and control system design for flexible rotors using active magnetic bearings (AMB) to pass through many critical speeds and fulfill high-speed rotation. To achieve this purpose, it is necessary to control not only motion but also many modes of bending vibration. For the purpose, an extended reduced order physical model that is able to express simultaneously the motion and bending vibration of the flexible rotor, is proposed. Furthermore, a new controller combined PID with LQ control is adapted to control the flexible rotor. Effectiveness of the proposed modeling and control approach for the flexible rotor is verified through simulations and experiments.

scholarly journals A 35,000 RPM Test Rig for Magnetic, Hybrid and Back-Up Bearings

1999 ◽  
Author(s):  
Erik E. Swanson ◽  
James F. Walton ◽  
Hooshang Heshmat
Keyword(s):  
High Speed ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Test Rig ◽  
Low Loss ◽  
Dynamic Motion ◽  
Speed Test ◽  
Bearing Loads ◽  
Amb System ◽  
Overload Capacity

Magnetic bearings have long offered the potential for significant turbomachinery system improvements due to their oil-free, non-contact, low loss nature and their ability to actively control shaft dynamic motion. However, end-users and many designers are hesitant to apply this technology. There are two basic stumbling blocks: active magnetic bearings (AMBs) have little overload capacity, and failure of any portion of the AMB system could result in catastrophic damage to the machine. To cope with both of these problems, a secondary back-up bearing must be included in the system. This paper describes a new full scale, high speed test rig which has the capability to test a variety of back-up bearings at speeds of up to 35,000 RPM, and bearing loads of up to 6.7 kN. Preliminary data for two novel back-up bearings are presented as a demonstration of the test rig’s capabilities.

Dynamic Modeling and Analysis of Active Magnetic Bearings

2014 ◽  
Vol 494-495 ◽  
pp. 685-688
Author(s):  
Rong Gao ◽  
Gang Luo ◽  
Cong Xun Yan
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Modeling ◽  
Magnetic Bearing ◽  
Integrated System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Modeling And Analysis ◽  
Amb System ◽  
Mathematics Method

Active magnetic bearing (AMB) system is a complex integrated system including mechanics, electronic and magnetism. In order to research for the basic dynamic characteristic of rotor supported by AMB, it is necessary to present mathematics method. The dynamics formula of AMB is established using theory means of dynamics of rotator and mechanics of vibrations. At the same tine, the running stability of rotor is analyzed and the example is presented in detail.

Modeling and Vibration Control of a Flexible Rotor by Using Magnetic Bearings

2011 ◽  
Author(s):  
Takuya Nomoto ◽  
Daisuke Hunakoshi ◽  
Toru Watanabe ◽  
Kazuto Seto
Keyword(s):  
Control System ◽  
Control Method ◽  
Design Procedure ◽  
Modeling Method ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Flexible Rotor ◽  
Modeling And Control ◽  
Elastic Modes ◽  
And Control

This paper presents a new modeling method and a control system design procedure for a flexible rotor with many elastic modes using active magnetic bearings. The purpose of our research is to let the rotor rotate passing over the 1st and the 2nd critical speeds caused by flexible modes. To achieve this, it is necessary to control motion and vibration of the flexible rotor simultaneously. The new modeling method named as Extended Reduced Order Physical Model is presented to express its motion and vibration uniformly. By using transfer function of flexible rotor-Active Magnetic Bearings system, we designed a Local Jerk Feedback Control system and conducted stability discrimination with root locus. In order to evaluate this modeling and control method, levitation experimentation is conducted.

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