Full-Size Rotordynamic Test Rig for Magnetic and Auxiliary Bearing Testing and Initial Results

2012 ◽  
Author(s):  
Oscar De Santiago ◽  
Víctor Solórzano ◽  
Sergio Díaz
Keyword(s):  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Test Rig ◽  
Transient Event ◽  
Electric Motor Drives ◽  
Compressor Rotor ◽  
Rotor Support ◽  
Rotor Stator Interaction ◽  
Auxiliary Bearing ◽  
Floating Platforms

Recent challenges in turbocompresor design include applications in subsea installations as well as remote operation in unmanned floating platforms. These applications benefit from oil-free operation which solves technical hurdles while being environmentally friendly. The most mature oil-free rotor support technology today is the magnetic bearing which is being used by several manufacturers as their standard solution to these advanced applications. These systems require auxiliary bearings to contain the rotor in case of a power failure to the magnetic bearings or a transient event. In general, there exists the need to develop commercial solutions for auxiliary bearings to extend its life, in particular regarding cumulative damage associated to drop events. This paper presents the design of a configurable test rig that can accommodate different rotor sizes, up to 1200 mm in bearing span, and 711 mm diameter wheels. The rig can also accommodate bearing sizes up to 229 mm. Rig pedestals can fit different bearing types such as magnetic bearings and/or auxiliary bearings independently, including oil bearings for comparison purposes. Misalignment and support flexibility effects are also possible. A 15.5 kW, variable speed electric motor drives the test rotor up to a speed limit of 10,000 rpm. Initial experiments on auxiliary bearings are shown for a 5-impeller, 57.8 kg, subcritical compressor rotor without drop events to study the baseline dynamic behavior of roller-element bearings (with inner clearance) on soft supports (o-rings). These experiments are presented to illustrate non-linear vibration regimes present during rotor-stator interaction with a highly unbalanced rotor. Experimental evidence presented can be used to fine-tune current auxiliary bearingmodels to improve rotordynamic predictive codes.

A Gas Turbine Engine Backup Bearing Operating Beyond 2.5 Million DN

2000 ◽  
Author(s):  
Erik Swanson ◽  
James F. Walton ◽  
Hooshang Heshmat
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Gas Turbine Engine ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Test Rig ◽  
Turbine Engine ◽  
Post Test ◽  
Rotor Support ◽  
Auxiliary Bearing

Gas turbine engines and high speed rotating machinery using magnetic bearings require auxiliary and backup bearings for reliability and safety of operation. A 140 mm diameter Zero Clearance Auxiliary Bearing (ZCAB) capable of supporting radial and/or thrust loads of up to 4500 N was designed for an advanced gas turbine engine. The ZCAB was fabricated and tested successfully up to the expected maximum operating speed of 18,000 rpm in a specially configured test rig. The test rig included a 36,000 rpm capable drive motor, a 64 kg rotor which simulates a gas turbine engine shaft dynamics, a damped ball bearing at the drive end and an active magnetic bearing next to the ZCAB. Operation in excess of 240 minutes and 20 transient engagements simulating magnetic bearing failures were completed in the initial tests. Post test inspection revealed minimal wear to the shaft and the ZCAB rollers, whereupon the ZCAB was reassembled for shipment. These preliminary tests confirm the operation and durability of the ZCAB in maintaining rotor support and continued operation even if the primary magnetic bearing support is overloaded or encounters a failure.

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.

Fault detection and tolerance in synchronous vibration control of rotor—magnetic bearing systems

2001 ◽  
Vol 215 (12) ◽  
pp. 1401-1416 ◽  
Author(s):  
M N Sahinkaya ◽  
M O T Cole ◽  
C R Burrows
Keyword(s):  
Vibration Control ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Magnetic Bearings ◽  
Control Technique ◽  
Effective Control ◽  
System Response ◽  
Rotor Support ◽  
Measured System ◽  
Control Forces

The use of magnetic bearings in rotating machinery provides contact-free rotor support, and allows vibration control using both closed-loop and open-loop strategies. One of the simplest and most effective methods to reduce synchronous lateral vibration when using magnetic bearings is through an open-loop adaptive control technique, in which the amplitude and phase of synchronous magnetic control forces are adjusted automatically to minimize the measured vibrations along the rotor. However, transducer malfunction, or faults in the signal-processing channels, may cause the controller to adapt incorrectly, with unwanted and possibly catastrophic effects. It is shown that an extension to the control strategy, which utilizes the variances of the measured system response and identified parameters, enables the faults to be detected and accounted for so that a modified control action can achieve continued and effective control of the synchronous vibration. The approach is extended further to identify changes in external factors, such as unbalance and rotor dynamics. Various faults and perturbations are examined experimentally, and the ability of the controller to detect and compensate for these changes is demonstrated.

Magnetic Bearing Improvement Program at NOVA

1996 ◽  
Author(s):  
Paul S. Alves ◽  
Barry M. Alavi
Keyword(s):  
Quality Control ◽  
Poor Quality ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Rapid Expansion ◽  
Improvement Program ◽  
Auxiliary Bearing ◽  
Gas Seals ◽  
Program Challenges

Nova Gas Transmission Ltd., located in Alberta, Canada, has lead the way in the application of dry gas seals and magnetic bearings to centrifugal compressors in gas pipeline service. The introduction of magnetic bearings in the NGTL system started in 1986 and to date some 34 units were installed. There are presently 31 units running with magnetic bearings due to some units being retired. It was part of NGTL vision to pursue the application of technologies holding promise of increased efficiencies for the pipeline. The installation of units with magnetic bearings had coincided with a period of rapid expansion of the pipeline in which there were limited resources and time available to assess equipment performance. Well into the magnetic bearing program, challenges associated with the magnetic bearing systems started to accumulate to a point where a serious study was warranted. These were in essence, the incidence of unit shutdowns, failure of components, and ultimately some instances of internal rubs of the rotating elements of the compressors. A complete technical audit of the magnetic bearing installed base at NGTL was conducted to evaluate potential improvements to the system, improve the knowledge of NGTL personnel in the relevant technical aspects, and set the foundation for on-going management of the technology. This audit effort pointed out several areas for improvement and a number of remedies were selected for implementation; mostly changes in the control system design, auxiliary bearing layout, and quality control of the installation. The changes proposed have been implemented in 18 units during 1995, with some other 6 planned for 1996. The results were excellent with the reliability of the upgraded units reaching virtually 100%. It should be pointed out that these 18 units have now accumulated 22,000 hours in service throughout the year. The most important part of this program is however, the Quality Control of the installations. We can say most of our problems in the past could certainly be attributed to poor quality control and should not be seen as an indictment of the magnetic bearings. There is optimism about the magnetic bearing performance and the long term benefits of using this technology.

A Design of Simulation Experiment System for the Helium Turbine

2012 ◽  
Author(s):  
Liang Zhu ◽  
Zhengang Shi
Keyword(s):  
Simulation Experiment ◽  
Cooling System ◽  
Aerodynamic Force ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Radial Load ◽  
Monitoring And Control ◽  
Experiment System ◽  
Compressor Rotor ◽  
Load Simulator

In this paper a new design of simulation experiment system for the helium turbine is described. This experiment system is for to study the rotor dynamic performance of the helium turbine in a 10 MW high temperature reactor-based helium turbine (HTR-10GT) power generation project. The system is a vertical and biaxial arrangement. The motor rotor is on one axis and the turbine-compressor rotor is another axis. The two axes are connected by a gear box having a gear ratio of 1:5 and two couplers. The motor has a rate speed of 3,000rpm, and the turbine-compressor rotor 15,000 rpm. The turbine-compressor rotor, which is simulated, has a mass of 646 kg, a length of 3,568mm, and is supported by two radial magnetic bearings along with an axial magnetic bearing. The design load carrying capacity of the axial magnetic bearing is 9.8 kN with a clearance of 0.7mm and the radial magnetic bearing is 1.96 kN with a clearance of 0.6mm. For simulating the aerodynamic force and the unbalanced force on the turbine-compressor rotor when it was turning, we designed a magnetic load simulator which can exert axial and radial load to the rotor directly. The design axial load of the magnetic load simulator is 10kN and the radial load is 715N both with a clearance of 1mm. The whole simulation experiment system includes the ventilation and cooling system and monitoring and control system. It is the first time that the simulation test has been run for the vertical helium turbine with magnetic bearings, running at full speed. The turbine-compressor rotor will pass through the critical speeds for the first and second order of bending, before reaching the rated speed. The magnetic load simulator can exert load quickly and directly, and the load form can be changed online, which is a new application way for the magnetic bearing.

Simple Model for a Magnetic Bearing System Operating on the Auxiliary Bearing

2005 ◽  
Author(s):  
E. N. Cuesta ◽  
N. I. Montbrun ◽  
V. Rastelli ◽  
S. E. Diaz
Keyword(s):  
Systems Analysis ◽  
Magnetic Bearing ◽  
Flexible Rotor ◽  
Periodic Motions ◽  
Test Rig ◽  
Magnetic Actuator ◽  
Auxiliary Bearing ◽  
Non Linear Systems ◽  
System Operating ◽  
Bearing System

The present work studies the behavior of a magnetic bearing supported rotor when the flow of electric current to the magnetic actuator is suppressed In this condition the rotor is supported by the auxiliary bearing, which has looseness with the rotor, generating a series of impacts between these components. For the study of this state, a model of a flexible rotor is proposed, and the impacts are simulated using kinematical restitution coefficient theory. The results obtained from the theoretical model are compared with experimental data taken on a test rig using tools for non linear systems analysis such bifurcation diagrams. The comparison shows that, besides the simplification of the contact, the model predicts ranges chaotic, quasi-periodic, and periodic motions in the test rig.

Modeling of a High Speed Rotor Test Rig With Active Magnetic Bearings

2005 ◽  
Vol 128 (3) ◽  
pp. 269-281 ◽  
Author(s):  
Guoxin Li ◽  
Zongli Lin ◽  
Paul E. Allaire ◽  
Jihao Luo
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Model Updating ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Behavior Modeling ◽  
Analytical Models ◽  
System Component ◽  
Test Rig ◽  
Experimental Identification

This paper reports on the modeling and experimental identification of a high speed rotor-magnetic bearing test rig. An accurate nominal model and an uncertainty representation are developed for robust controller synthesis and analysis. A combination of analytical modeling, model updating, and identification is employed for each system component and for the system as a whole. This approach takes advantage of both the behavior modeling and input/output modeling methods. Analytical models of the rotor and the magnetic bearings are first developed from physical laws and refined by comparison with the experimental data. The substructure model is directly identified from the experimental data by a structured identification approach. Models of the electronic systems, such as the filters, amplifiers, sensors, and digital controller, are developed through experimental identification. These component models are then assembled to obtain the overall system model. Closed-loop tests are conducted to identify parameters in the model. Advanced control techniques based on H∞ control and μ synthesis are developed and successfully implemented on the test rig, which further validates the model.

Characteristics of a Magnetically Levitated Flexible Rotor When in Contact With One or More Auxiliary Bearings

2005 ◽  
Author(s):  
Patrick S. Keogh ◽  
Yuan Hui Seow ◽  
Matthew O. T. Cole
Keyword(s):  
Dynamic Response ◽  
Magnetic Bearing ◽  
Contact Dynamics ◽  
Magnetic Bearings ◽  
System Model ◽  
Flexible Rotor ◽  
Contact Conditions ◽  
Contact Parameter ◽  
Auxiliary Bearing ◽  
Non Linear System

The case for installing auxiliary bearings in parallel with magnetic bearings is often made with regard to touchdown, when a complete system failure occurs. The work reported in this paper focuses on the case when rotor/auxiliary bearing contact occurs, but the magnetic bearings retain their functionality. One may envisage future transportation applications in which this situation would occur, for example, during high acceleration levels induced by turbulence. An understanding of the rotor dynamic response during contact conditions could enable auxiliary bearing life expectancy to be extended using appropriate control action from the still functional magnetic bearings. To achieve this, a system model is required for control strategy design purposes. This paper considers the development of a non-linear system model for predicting the contact dynamics in a flexible rotor/magnetic/auxiliary bearing system. Previous experimental work produced similar contact dynamic response characteristics; whether due to unbalance or circular forcing through a magnetic bearing. Initial model-based predictions of these tests did not provide sufficiently accurate reproduction of the measured orbits, particularly in the presence of auxiliary bearing misalignment and multi-plane rotor contact. Parameter variations are thus undertaken to investigate the reasons for these differences. Contrary to expectations, uncertainty in the magnetic bearing characteristics during contact conditions appears to offer an explanation.

scholarly journals Condition Monitoring of Active Magnetic Bearings on the Internet of Things

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Alexander Pesch ◽  
Peter Scavelli
Keyword(s):  
Internet Of Things ◽  
Condition Monitoring ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Raspberry Pi ◽  
The Internet ◽  
Active Magnetic Bearings ◽  
Network Computing ◽  
Test Rig ◽  
The Internet Of Things

A magnetic bearing is an industrial device that supports a rotating shaft with a magnetic field. Magnetic bearings have advantages such as high efficiency, low maintenance, and no lubrication. Active magnetic bearings (AMBs) use electromagnets with actively controlled coil currents based on rotor position monitored by sensors integral to the AMB. AMBs are apt to the Internet of Things (IoT) due to their inherent sensors and actuators. The IoT is the interconnection of physical devices that enables them to send and receive data over the Internet. IoT technology has recently rapidly increased and is being applied to industrial devices. This study developed a method for the condition monitoring of AMB systems online using off-the-shelf IoT technology. Because off-the-shelf IoT solutions were utilized, the developed method is cost-effective and can be implemented on existing AMB systems. In this study, a MBC500 AMB test rig was outfitted with a Raspberry Pi single board computer. The Raspberry Pi monitors the AMB’s position sensors and current sensors via an analog-to-digital converter. Several loading cases were imposed on the experimental test rig and diagnosed remotely using virtual network computing. It was found that remote AMB condition monitoring is feasible for less than USD 100.

Preliminary Research of Auxiliary Bearing in HTR-10GT Project

2008 ◽  
Author(s):  
Qingquan Qin ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Suyuan Yu
Keyword(s):  
Reference Value ◽  
Free Fall ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Main Function ◽  
Test Results ◽  
Test Rig ◽  
Advantages And Disadvantages ◽  
Auxiliary Bearing ◽  
Amb System

Active Magnetic Bearing (AMB) was used in the project of 10MW high temperature gas-cooled reactor (HTR-10GT) for the advantages over conventional mechanical bearings: without any mechanical friction and lubrication, etc. Auxiliary Bearings (ABs) is one of the most important parts in the AMB system, and its main function is to support the rotor at rest and provide protection for the rotor system during an overload or magnetic bearings failure situation. This paper introduced auxiliary bearings used in the HTR-10GT project and compared its advantages and disadvantages with other types of auxiliary bearings. The dynamic behaviors and temperature variation are the most important factors that may affect the performance of auxiliary bearings in a rotor drop event, this paper also analyzed the touching down course and dynamics in detail, divided the drop down process into four distinct stages of motion: free fall, impact, sliding-whirling and rolling. Finally, a test rig built up for the following rotor drop test is presented in the article. Test results at lower drop down speed were discussed. The result of the theory and experiment research has important reference value for the auxiliary bearings design of HTR-10GT.

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