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You searched for subject:(Homopolar magnetic bearings). Showing records 1 – 2 of 2 total matches.

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Texas A&M University

1. Kang, Kyungdae. Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation.

Degree: 2011, Texas A&M University

An objective in the design of high performance machinery is to minimize weight so magnetic bearings are often designed to operate slightly lower than the magnetic material saturation. Further weight reduction in the bearings requires operation in the nonlinear portion of the B-H curve. This necessitates a more sophisticated analysis at the bearing and rotordynamic system levels during the design stage. This dissertation addresses this problem in a unique manner by developing a fully nonlinear homopolar magnetic bearing model. The nonlinear dynamics of permanent magnet-biased homopolar magnetic bearing (PMB HoMB) system with 2-dof rigid and 4-dof flexible rotor is analyzed. The dynamic behavior of the rotor-bearing system is examined in the feedback control loop that includes low pass filter effects. An analytical magnetization curve model is proposed to predict the nonlinear magnetic force under the influence of the magnetic flux saturation more accurately. The modified Langmuir method with the novel correction terms for the weak flux region is used to curve-fit the experimental magnetization data of Hiperco 50. A new curve fit model of the B-H curve is shown to have significantly better agreement with the measured counterpart than conventional piecewise linear and other models. PMB HoMB characteristics with flux saturation, such as forces depending on the rotor position and bearing stiffness, are compared with these other models. Frequency response curve, bifurcation diagram, Poincare plot, and orbit plot are utilized to demonstrate the effects of the nonlinearities included in the 2-dof rotorbearing system. Due to heavy static loads applied to the rotor, it operates within the magnetic flux saturation region at the bearing clearance. The voltage saturation in the power amplifier of the magnetic bearing introduces lag in the control loop and the response of the heavily loaded 4-dof rotor-bearing system shows that limit cycle stability can be achieved due to the magnetic flux saturation or current saturation in the amplifier; otherwise the system would experience a destructive instability. These simulation results provide the first explanation of this commonly observed limit cycle which is referred to as ?virtual catcher bearings?. Advisors/Committee Members: Palazzolo, Alan B. (advisor), Swaroop, Darbha (committee member), Langari, Reza (committee member), Strganac, Thomas W. (committee member).

Subjects/Keywords: Nonlinear dynamics; Homopolar magnetic bearings; Saturation; Limit cycle

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kang, K. (2011). Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8902

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Kang, Kyungdae. “Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation.” 2011. Thesis, Texas A&M University. Accessed October 19, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8902.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Kang, Kyungdae. “Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation.” 2011. Web. 19 Oct 2019.

Vancouver:

Kang K. Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation. [Internet] [Thesis]. Texas A&M University; 2011. [cited 2019 Oct 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8902.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kang K. Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation. [Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8902

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Texas A&M University

2. Gandhi, Varun R. High Temperature, Permanent Magnet Biased Magnetic Bearings.

Degree: 2010, Texas A&M University

The Electron Energy Corporation (EEC) along with the National Aeronautics and Space Administration (NASA) is researching magnetic bearings. The purpose of this research was to design and develop a high-temperature (1000?F) magnetic bearing system using High Temperature Permanent Magnets (HTPM), developed by the EEC. The entire system consisted of two radial bearings, one thrust bearing, one motor and 2 sets of catcher bearings. This high temperature magnetic bearing system will be used in high performance, high speed and high temperature applications like space vehicles, jet engines and deep sea equipment. The bearing system had a target design to carry a load equal to 500 lb-f (2225N). Another objective was to design and build a test rig fixture to measure the load capacity of the designed high temperature radial magnetic bearing (HTRMB) called Radial Bearing Force Test Rig (RBFTR). A novel feature of this high temperature magnetic bearing is its homopolar construction which incorporates state of the art high temperature, 1000 ?F, permanent magnets. A second feature is its fault tolerance capability which provides the desired control forces even if half the coils have failed. The permanent magnet bias of the radial magnetic bearing reduces the amount of current required for magnetic bearing operation. This reduces the power loss due to the coil current resistance and also increases the system efficiency because magnetic field of the HTPM is used to take up the major portion of the static load on the bearing. The bias flux of the homopolar radial bearing is produced by the EEC HTPM to reduce the related ohmic losses of an electromagnetic circuit significantly. An experimental procedure was developed using the Radial Bearing Force Test Rig (RBTFR) to measure actual load capacity of the designed bearing at the test rig. All the results obtained from the experiment were compiled and analyzed to determine the relation between bearing force, applied current and temperature. Advisors/Committee Members: Palazzolo, Alan B. (advisor), Rasmussen, Bryan P. (committee member), Vadali, Srinivas R. (committee member).

Subjects/Keywords: Temperature; High Temperature; magnets; Permanent magnet Biased; Homopolar; radial magnetic bearing; bearings

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gandhi, V. R. (2010). High Temperature, Permanent Magnet Biased Magnetic Bearings. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Gandhi, Varun R. “High Temperature, Permanent Magnet Biased Magnetic Bearings.” 2010. Thesis, Texas A&M University. Accessed October 19, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Gandhi, Varun R. “High Temperature, Permanent Magnet Biased Magnetic Bearings.” 2010. Web. 19 Oct 2019.

Vancouver:

Gandhi VR. High Temperature, Permanent Magnet Biased Magnetic Bearings. [Internet] [Thesis]. Texas A&M University; 2010. [cited 2019 Oct 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gandhi VR. High Temperature, Permanent Magnet Biased Magnetic Bearings. [Thesis]. Texas A&M University; 2010. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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