scholarly journals A Vibration Sensor-Based Method for Generating the Precise Rotor Orbit Shape with General Notch Filter Method for New Rotor Seal Design Testing and Diagnostics

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5249
Author(s):  
Karel Kalista ◽  
Jindrich Liska ◽  
Jan Jakl
Keyword(s):  
Notch Filter ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Harmonic Vibration ◽  
Filter Method ◽  
Vibration Exciter ◽  
Active Magnetic Bearings ◽  
Rotor Vibration ◽  
Seal Design ◽  
Exact Shape

Verification of the behaviour of new designs of rotor seals is a crucial phase necessary for their use in rotary machines. Therefore, experimental equipment for the verification of properties that have an effect on rotor dynamics is being developed in the test laboratories of the manufacturers of these components all over the world. In order to be able to compare the analytically derived and experimentally identified values of the seal parameters, specific requirements for the rotor vibration pattern during experiments are usually set. The rotor vibration signal must contain the specified dominant components, while the others, usually caused by unbalance, must be attenuated. Technological advances have made it possible to use magnetic bearings in test equipment to support the rotor and as a rotor vibration exciter. Active magnetic bearings allow control of the vibrations of the rotor and generate the desired shape of the rotor orbit. This article presents a solution developed for a real test rig equipped with active magnetic bearings and rotor vibration sensors, which is to be used for testing a new design of rotor seals. Generating the exact shape of the orbit is challenging. The exact shape of the rotor orbit is necessary to compare the experimentally and numerically identified properties of the seal. The generalized notch filter method is used to compensate for the undesired harmonic vibrations. In addition, a novel modified generalized notch filter is introduced, which is used for harmonic vibration generation. The excitation of harmonic vibration of the rotor in an AMB system is generally done by injecting the harmonic current into the control loop of each AMB axis. The motion of the rotor in the AMB axis is coupled, therefore adjustment of the amplitudes and phases of the injected signals may be tedious. The novel general notch filter algorithm achieves the desired harmonic vibration of the rotor automatically. At first, the general notch filter algorithm is simulated and the functionality is confirmed. Finally, an experimental test device with an active magnetic bearing is used for verification of the algorithm. The measured data are presented to demonstrate that this approach can be used for precise rotor orbit shape generation by active magnetic bearings.

Frequency Analysis of the Orbit Responses of Active Magnetic Bearings in Touchdown Using Hilbert Transform

2017 ◽  
Vol 17 (08) ◽  
pp. 1750086 ◽  
Author(s):  
Mindong Lyu ◽  
Zixi Wang ◽  
Tao Liu ◽  
Xiaohong Jia ◽  
Yuming Wang
Keyword(s):  
Working Conditions ◽  
Hilbert Transform ◽  
Instantaneous Frequency ◽  
Magnetic Bearing ◽  
Contact Forces ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Analysis Model ◽  
Rotor Vibration ◽  
Significant Difference

Touchdown bearing (TDB) is one of the key elements in active magnetic bearings (AMBs). When the magnetic bearing fails or is exposed to an overload, touchdown events will occur. According to ISO 14839, three typical orbit responses (pendulum vibration, combined rub and bouncing, and full rub) can be detected in touchdown events. The magnitude of the dynamic forces between the rotor and TDBs has been considered as an indicator to identify these orbit responses. However, the contact forces may not be easy to measure with precision. The instantaneous frequency of the rotor vibration is another significant difference between them. In this paper, a performance analysis model has been established that considers the dynamic and thermal effects in touchdown events. Simulations under different working conditions have been conducted and a recommendation for safety working conditions of the AMB system has been developed. The instantaneous frequency of the rotor vibration has been computed using Hilbert transform and the frequency characteristics of the three orbit responses have been analyzed and discussed. The results reveal that the instantaneous frequency of the pendulum vibration is almost fixed. The instantaneous frequency of the combined rub and bouncing fluctuates vehemently in most cases. The instantaneous frequency of the backward whirl shows periodic regularity.

The μ Approach to Control of Active Magnetic Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 566-570 ◽  
Author(s):  
R. L. Fittro ◽  
C. R. Knospe
Keyword(s):  
Laboratory Test ◽  
Rotating Machinery ◽  
Vibration Response ◽  
Experimental Results ◽  
Magnetic Bearings ◽  
Pd Controller ◽  
Active Magnetic Bearings ◽  
Test Rig ◽  
Rotor Vibration ◽  
Multivariable Controller

Many important industrial problems in the control of rotating machinery with active magnetic bearings concern the minimization of the rotor vibration response to poorly characterized disturbances at a single or several shaft locations, these typically not corresponding to those of a sensor or actuator. Herein, we examine experimental results of a multivariable controller obtained via μ synthesis with a laboratory test rig. These indicate that a significant improvement in performance can be obtained with a multivariable μ controller over that achieved with an optimal decentralized PD controller.

The μ Approach to Control of Active Magnetic Bearings

2000 ◽  
Author(s):  
Roger L. Fittro ◽  
Carl R. Knospe
Keyword(s):  
Laboratory Test ◽  
Rotating Machinery ◽  
Vibration Response ◽  
Experimental Results ◽  
Magnetic Bearings ◽  
Pd Controller ◽  
Active Magnetic Bearings ◽  
Test Rig ◽  
Rotor Vibration ◽  
Multivariable Controller

Many important industrial problems in the control of rotating machinery with active magnetic bearings concern the minimization of the rotor vibration response to poorly characterized disturbances at a single or several shaft locations, these typically not corresponding to those of a sensor or actuator. Herein, we examine experimental results of a multivariable controller obtained via μ synthesis with a laboratory test rig. These indicate that a significant improvement in performance can be obtained with a multivariable μ controller over that achieved with an optimal decentralized PD controller.

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.

scholarly journals Development and Experimental Validation of Auxiliary Rolling Bearing Models for Active Magnetic Bearings (AMBs) Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Anna Tangredi ◽  
Enrico Meli ◽  
Andrea Rindi ◽  
Alessandro Ridolfi ◽  
Pierluca D’Adamio ◽  
...  
Keyword(s):  
Load Capacity ◽  
Critical Phenomenon ◽  
Magnetic Bearing ◽  
Design Tool ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Short Period ◽  
Auxiliary Bearing ◽  
Bearing System

Nowadays, the search for increasing performances in turbomachinery applications has led to a growing utilization of active magnetic bearings (AMBs), which can bring a series of advantages thanks to their features: AMBs allow the machine components to reach higher peripheral speeds; in fact there are no wear and lubrication problems as the contact between bearing surfaces is absent. Furthermore, AMBs characteristic parameters can be controlled via software, optimizing machine dynamics performances. However, active magnetic bearings present some peculiarities, as they have lower load capacity than the most commonly used rolling and hydrodynamic bearings, and they need an energy source; for these reasons, in case of AMBs overload or breakdown, an auxiliary bearing system is required to support the rotor during such landing events. During the turbomachine design process, it is fundamental to appropriately choose the auxiliary bearing type and characteristics, because such components have to resist to the rotor impact; so, a supporting design tool based on accurate and efficient models of auxiliary bearings is very useful for the design integration of the Active Magnetic Bearing System into the machine. This paper presents an innovative model to accurately describe the mechanical behavior of a complete rotor-dynamic system composed of a rotor equipped with two auxiliary rolling bearings. The model, developed and experimentally validated in collaboration with Baker Hughes a GE company (providing the test case and the experimental data), is able to reproduce the key physical phenomena experimentally observed; in particular, the most critical phenomenon noted during repeated experimental combined landing tests is the rotor forward whirl, which occurs in case of high friction conditions and greatly influences the whole system behavior. In order to carefully study some special phenomena like rotor coast down on landing bearings (which requires long period of time to evolve and involves many bodies and degrees of freedom) or other particular events like impacts (which occur in a short period of time), a compromise between accuracy of the results and numerical efficiency has been pursued. Some of the elements of the proposed model have been previously introduced in literature; however the present work proposes some new features of interest. For example, the lateral and the axial models have been properly coupled in order to correctly reproduce the effects observed during the experimental tests and a very important system element, the landing bearing compliant suspension, has been properly modelled to more accurately describe its elastic and damping effects on the system. Furthermore, the model is also useful to characterize the frequencies related to the rotor forward whirl motion.

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.

The Oil-Free Shaft Line

1988 ◽  
Author(s):  
Bruno Wagner
Keyword(s):  
Vibration Control ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Present Stage ◽  
Shaft Line ◽  
Process Gas ◽  
Gas Seals ◽  
Length Reduction

This paper recalls the principles and main features of the active magnetic bearings and especially the advantages for turbomachines. Oil-free working and vibration control are part of them. Field experiences are described for different shaft line configurations. Step by step we are going to get totally rid of oil with the introduction of active magnetic bearings together with dry gas seals and gearless drive. Future machines will take the benefit of all this field experience. The trend of the design optimization is the active magnetic bearings in the process gas itself, for a length reduction of shafts. But at the present stage, the active magnetic bearing is a proven technology today.

scholarly journals The Application of Active Magnetic Bearings to a Natural Gas Pipeline Compressor

1986 ◽  
Author(s):  
E. G. Foster ◽  
V. Kulle ◽  
R. A. Peterson
Keyword(s):  
Natural Gas ◽  
Economic Assessment ◽  
Magnetic Bearing ◽  
Gas Pipeline ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Dry Gas Seal ◽  
Natural Gas Pipeline ◽  
Operational Data

The installation and operation of an active magnetic bearing in conjunction with a modified mechanical dry gas seal on a natural gas pipeline compressor is presented. The emphasis of this paper is centered on the active magnetic bearing. The active magnetic bearing was developed by Société de Mécanique Magnétique (S2M) of Vernon France. The first successful application to a natural gas pipeline compressor was a co-operative effort between NOVA, AN ALBERTA CORPORATION, S2M, and Magnetic Bearing Incorporated (MBI) of Radford, Virginia. This paper represents a technical and economic assessment of the bearing, including installation and operational data.

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