Self-Powered Eddy Current Damper for Rotordynamic Applications

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Mario Silvagni ◽  
Andrea Tonoli ◽  
Angelo Bonfitto
Keyword(s):  
Eddy Current ◽  
Rotating Shaft ◽  
Electric Generator ◽  
Three Phase ◽  
Rolling Element ◽  
Transformer Type ◽  
Eddy Current Damper ◽  
Self Powered ◽  
Fluid Dampers ◽  
Absence Of Power

The vibration control of rotors is often performed using elastomeric or fluid dampers together with rolling element or hydrodynamic type bearings. Electromagnetic dampers seem a valid alternative to conventional solutions and also to active magnetic bearings (AMBs) because their simpler architecture, size and, if of transformer type, also for the absence of power electronics, position sensors, and any fast feedback loop. However, transformer eddy current dampers require a constant voltage power supply than can be provided by an embedded generator to reduce cost and improve the reliability. The present paper proposes a self-powered damper to fulfill these requirements. A three-phase permanent magnet electric generator (connected to the rotating shaft) generates the required power for the damping device. The generator is connected to the damping circuit by means of tuned impedance and a three-phase rectifier.

Operation of an Electromagnetic Eddy-Current Damper with a Supercritical Shaft

1994 ◽  
Vol 116 (4) ◽  
pp. 578-580 ◽  
Author(s):  
J. R. Frederick ◽  
M. S. Darlow
Keyword(s):  
Eddy Current ◽  
High Speed ◽  
Eddy Currents ◽  
Squeeze Film ◽  
Future Research ◽  
Rotating Shaft ◽  
Small Disk ◽  
Eddy Current Damper ◽  
Speed Stability

A basic problem inherent with the operation of supercritical shafting is the application of appropriate external damping, which is generally necessary to suppress nonsynchronous instabilities and limit the synchronous response of even a well-balanced shaft. Typically, coulomb or squeeze film-type dampers are used, in which case the damping properties tend to change with temperature, and the necessary contact results in additional torque loading and wear. An alternative damping method currently under investigation is the application of a noncontact electromagnetic damper that dissipates energy through induced eddy-currents generated in a small disk mounted to, and rotating with the shaft (Frederick, 1990). Research is underway on the design and development of a damper of this type that could eventually lend itself to active control applications. The objectives of this investigation are the initial design of a magnetic circuit, an appropriate d-c power supply, and the characterization of preliminary performance experiments on a composite shaft. Damper operation was evaluated during rotating shaft tests and compared to prior tests which involved the use of a permanent magnet eddy-current damper. This Note concerns some interesting results obtained from these preliminary tests. The damper worked well at low speeds, but some high-speed stability problems were encountered. Potential solutions to these problems as well as areas of future research are discussed.

scholarly journals Multi-objective design optimization of a permanent magnet axial flux eddy current brake

2019 ◽  
pp. 998-1011
Author(s):  
RASUL TARVIRDILU ASL ◽  
HÜSEYİN MURAT YÜKSEL ◽  
OZAN KEYSAN
Keyword(s):  
Eddy Current ◽  
Effect Of Temperature ◽  
Test Results ◽  
Algorithm Optimization ◽  
Axial Flux ◽  
Multiobjective Genetic Algorithm ◽  
Aerospace Applications ◽  
Eddy Current Damper ◽  
Brake Performance ◽  
Speed Characteristic

The main aim of this study is to optimize an axial flux eddy current damper to be used in a specific aviation application. Eddy current dampers are more advantageous compared to conventional mechanical dampers as they are maintenance-free due to contactless structure and have higher reliability, which is very desirable in aerospace applications. An initial eddy current brake prototype is manufactured and the test results are used to verify the 3-D finite element simulations. The effect of temperature on the brake performance is investigated. Finally, a multiobjective genetic algorithm optimization is applied to find the optimum pole number and geometric dimensions of the eddy current brake in order to achieve the desired torque-speed characteristic while the total weight of the brake is minimized. It is found that the mass and volume of the initial prototype can be halved by implementing this optimization algorithm.

Design and Analysis of Eddy Current Damper

2021 ◽  
Author(s):  
Nitin Satpute ◽  
Marek Iwaniec ◽  
Ramesh Narina ◽  
Idris Presswala ◽  
Ludwin Molina Arias
Keyword(s):  
Eddy Current ◽  
Eddy Current Damper

Design Procedure of an Eddy Current Damper Type Reaction Force Compensation (RFC) Mechanism for a Linear Motor Motion Stage

2015 ◽  
Author(s):  
HyeongJoon Ahn
Keyword(s):  
Eddy Current ◽  
Reaction Force ◽  
Design Procedure ◽  
Linear Motor ◽  
Lumped Parameter Model ◽  
Magnetic Flux Density ◽  
Eddy Current Damper ◽  
Linear Motor Motion Stage ◽  
Motion Stage ◽  
Reaction Force Compensation

Base vibration of a linear motor motion stage has been reduced with passive RFC mechanism based on movable magnet track and springs. This paper presents design procedure of an eddy-current damper (ECD) type RFC mechanism for a linear motor motion stage. The RFC mechanism with a movable magnet track and an ECD can overcome disadvantages of the spring based RFC mechanism such as resonance and difficulty of assembly due to spring. A lumped parameter model for the ECD type RFC mechanism is derived considering sinusoidal magnetic flux density and effective width of the ECD according to magnet track motion. Then, a design procedure for ECD type RFC mechanism is proposed to meet system requirements such as transmission ratio of reaction force and maximum magnet track motion. Design example illustrates the effectiveness of the proposed design procedure for ECD type RFC mechanism.

Modeling of Eddy Current Damper Composed of Spherical Magnet and Conducting Shell

2006 ◽  
Author(s):  
Yoshihisa Takayama ◽  
Atsuo Sueoka ◽  
Takahiro Kondou
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Magnetic Force ◽  
Eddy Currents ◽  
Reaction Force ◽  
Damping Force ◽  
Magnetic Damping ◽  
Conducting Plate ◽  
Direction Of Movement ◽  
Eddy Current Damper

If a conducting plate moves through a nonuniform magnetic field, eddy currents are induced in the conducting plate. The eddy currents produce a magnetic force of drag, known as Fleming's left-hand rule. This rule means that a magnetic field perpendicular to the direction of movement generates a magnetic damping force. We have fabricated the eddy current damper composed of the spherical magnet and the conducting shell. The spherical magnet produces the axisymmetric magnetic field, and the shape of the conducting shell appears to combine a semispherical shell conductor and a cylinder conductor. When the eddy current damper works, the conducting shell is fixed in space, and the spherical magnet moves under the conducting shell. In this case, since there are magnetic flux densities perpendicular to the direction of movement, eddy currents flow inside the conducting shell, and then a magnetic force is produced. The reaction force of this magnetic force acts on the spherical magnet. In our study, eddy current dampers composed of a magnet and a conducting plate have been modeled using infinitesimal loop coils. As a result, magnetic damping forces are obtained. Our modeling has three merits as follows: the equation of a magnetic damping force is simple in the equation, we can use the static magnetic field obtained using FEM, the Biot-Savart law or experiments and the equation automatically satisfies boundary conditions using infinitesimal loop coils. In this study, we explain simply the principle of this method, and model an eddy current damper composed of a spherical magnet and a conducting shell. The analytical results of the modeling agree well with the experimental results.

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