• Tribology and Lubricants
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• v.13 no.2
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• pp.52-59
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• 1997

An experimental study is presented for the characteristics of the high temperature superconductor as an application of the repulsive type magnetic bearing. A ring shaped YBCO type superconductor and Neodium permanent magnets are employed for the experiment. For the case of field cooling, superconductor shows strong repulsive force, which is due to the Meissner effect, as the gap between the superconductor and the magnet gets closer. The repulsive force variation with respect to the gap change shows hysterisis characteristics. The area of the loop of the hysterisis curve represents the dissipation of energy, which reveals that the magnetic bearing with superconductor has large damping. The effect of the initial gap and the magnetic flux density on the repulsive force is analyzed experimentally and the static stiffness variation is calculated from the measured repulsive force variation. The relative sliding velocity between the superconductor and the magnet has little effect on the repulsive force which is quite different from the usual sliding element bearing. As the initial gap for the field cooling becomes larger, the maximum repulsive force at the minimum gap increases and approaches to the value for the case of zero field cooling.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.48-54
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• 1999

For the high speed linear motor and the transportation device at clean room, a magnetic levitation rail without contact using the repulsive force of permanent magnets was newly developed. The characteristics of repulsive and lateral forces of the magnetic levitating system using permanent magnet was studied and the devised magnetic levitating system was evaluated by analytical and experimental approaches. This system is composed of two fixed guide rails with the rare earth permanent magnet array and a moving unit which is attached two magnet pairs at each sides. Because this system was forcedly levitated by the face to face repulsive forces, levitating air gap length can be repulsive force of an auxiliary magnetic repulsion system on the center of moving unit.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.18-23
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• 1996

This paper proposes a new levitation scheme for EDS MAGLEV vehicle with AC superconducting magnet(ACSCM). The eddy current and the levitation force are generated at all speed including stand still in this scheme, therefore, the auxiliary wheels on DCSCM can be eliminated. To reduce the ac loss of the magnet, the ACSCM also can be operated as a DCASCM at high speed because levitation force generated by DCSCM is enough at high speed. To prove the effectiveness of the proposed scheme, the repulsive force and power loss versus frequency of ACSCM is calculated. For comparison, characteristics of DCSCM of same cross section versus speed are also given. (author). 6 refs., 9 figs.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.67-76
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• 1997

In this paper we developed a tactile feedback device using repulsive force of magnets. The force of the tactile feedback device was derived from the Maxwell's stress method by using the concept of magnetic charge. Magnetic repulsive force is linear function with respect to current and nonlinear to displacement. Experimental data shows these characteristics. To compensate the fact that the presented tactile feedback device can not be controlled by close loop control, we developed a simulation model which predicts output displacement and force by using Runge-Kutta method. And, this paper evaluated the presented tactile feedback device and compared it with commercial tactile feedback devices.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.923-925
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• 2008

As known generally, when permanent magnets whose poles are upward and downward in order, arranged into the circumferential direction rotate under the conducting plate, the rotating force acts on the plate as well as the repulsive force. If the magnetic field by the magnet wheel(the above rotating permanent magnets) is partially shielded, the magnet wheel over open region can be a linear induction motor. The distinct feature from induction motor is that the traveling magnet field is produced by the moving permanent magnet instead of ac current. Furthermore, a variation of the open region changes the direction of the thrust force. In this paper, we introduce a concept of the linear actuator using the magnet wheel. Under the above shielding condition, a few simulation results and its verification from a simple test setup are described.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.988-995
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• 2010

In this study the (Alnico, Sm-Co) bonded magnets were fabricated by mixing the Sm-Co added alnico alloy powders with epoxy resin and binder, appropriately. Also, the hybrid ring magnets of (Alnico, Sm-Co)/Sr-ferrite were fabricated by coupling the Sr-ferrite composite layer with an (Alnico, Sm-Co) magnet. The magnetic properties of (Alnico, Sm-Co) ring magnets were varied with the amount of Sm-Co powders. The addition of Sm-Co powders increased a remanent induction($B_r$) and coercive force($_BH_C$), while decreasing a surface flux density and repulsive distance. The surface flux density and repulsive distance for the (Alnico, Sm-Co) ring magnet increased with a magnetizing voltage up to about 160 V and reached an apparent saturation point. Also, the measurements of temperature and moisture characteristics showed that the surface flux densities of N-S poles and repulsive distance decreased a little within 4% after 10 days passed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.535-538
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• 2002

Suspension effect has been studied by using superconductor of BiPbSrCaCuO ceramics containing $Ag_2()$. It has been clear that $Ag_2()$ acts as pinning center which plays an important role to the suspension effect. Magnetic repulsive force which affects a superconductor located in magnetic flux from toroidal magnet, has been investigated. It has been concluded that the suspension effect arises from the interaction between the pinning effect and the diamagnetic effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.101-103
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• 2001

Suspension effect has been studied by using superconductor of BiPbSrCaCuO ceramics containing $Ag_{2}O$ It has been cleared that $Ag_{2}O$ acts as pinning center which plays an important role to the suspension effect. Magnetic repulsive force which affects a superconductor located in magnetic flux from toroidal magnet has been investigated. It has been concluded that the suspension effect arises from the interaction between the pinning effect and the diamagnetic effect.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.839-843
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• 2001

For robotic endoscope, some researchers suggest pneumatic actuators based on inchworm motion. But, the existing endoscopes are not seemed to be replaced completely because human intestine is very sensitive and susceptible to damage. We design and test a new locomotion of robotic endoscope able to maneuver safely in the human intestine. The actuating mechanism is composed of two solenoids at each side and a single permanent magnet. When the current direction is reversed, repulsive force and attractive at the opposition side propels permanent magnet. Impact force against robotic endoscope transfer momentum from moving magnet to endoscope capsule. The direction and moving speed of the actuator can be controlled by adjusting impact force. Modeling and simulation experiments are carried out to predict the performance of the actuator. Simulation experiments show that force profile of permanent magnet is the dominant factor for the characteristic of the actuator. The results of simulations are verified by comparing with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.109-116
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• 2010

The magnet wheel which generates on its interfacing conductive part a repulsive force and a traction torque by rotation of permanent magnets is used to manipulate the conductive plate without mechanical contact. Here, the air-gap magnetic field of the magnet wheel is shielded partially to convert the traction torque into a linear thrust force. Although a magnitude of the thrust force is constant under the fixed open region, we can change the direction of force by varying a position of the shield sheet. So, the spatial position of conductive plate is controlled by not the force magnitude from each magnet wheel but the open position of shield sheet. This paper discusses non-contact conveyance system of the conductive plate using electromagnetic forces from multiple magnet wheels.