Micro-Force Calibration with an All-Coil Magnetic Levitation

2005 ◽  
Vol 295-296 ◽  
pp. 95-100
Author(s):  
S.W. Hsu ◽  
T.L. Chen

A prototype all-coil electromagnetic force balance has been designed and built. This measurement system compares the mechanical force to an SI realization of electromagnetic force, which is driven from interaction of currents in radial coil set and levitation coil. The preliminary measurement results demonstrate that the magnetic field distribution and magnetic force output are consistent with the results by simulation.

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Shilei Ma ◽  
Shiyuan Pei ◽  
Lin Wang ◽  
Hua Xu

Vibrations caused by the imbalance of a rotor are a frequently encountered problem in machining processes. Especially in high-precision finishing, the workpiece quality is strongly related to the vibration of the machine-tool spindle, which is mainly caused by mass imbalance and cannot be completely eliminated in cutting tools with nonaxisymmetrical structures. An imbalance in centrifugal force is generated by rotor rotation and increases rapidly with rotational speed. A novel active online electromagnetic balancing method based on static magnetic-field analysis is proposed, and an active online electromagnetic balancing device (AOEBD) based on this method was developed under these conditions. The magnetic-field distribution and electromagnetic force generated by the device were analyzed by finite-element modeling. The influence on the electromagnetic force of the misalignment between the rotor and the iron core was investigated. Factors influencing the magnetic force of the device were determined, and reasonable reference values were suggested. The critical eccentricity was also provided. Experiments had been done at last, and the experimental results presented a good performance of this kind of balancing device.


1998 ◽  
Vol 551 ◽  
Author(s):  
E. Beaugnon ◽  
R. Tournwer

AbstractThe magnetic levitation of diamagnetic materials in a high field superconducting magnet is presented. The magnetic force is determined from numerical calculations of the magnetic field components and the stability of levitation is studied using energy calculations. Amongst the numerous materials that can be levitated, experiments are shown for ethanol droplets.


Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.


2014 ◽  
Vol 85 (2) ◽  
pp. 023506 ◽  
Author(s):  
G. Z. Zuo ◽  
J. S. Hu ◽  
J. Ren ◽  
Z. Sun ◽  
Q. X. Yang ◽  
...  

Author(s):  
Thomas W. Anderson ◽  
Nathaniel A. Clark ◽  
Wesley E. Kotz ◽  
Briana D. Stremick ◽  
O¨zer Arnas ◽  
...  

Recent additions of armor have made light tactical vehicle turrets heavy enough that mechanical assistance is required for them to rotate. The Army’s solution is the Battery Powered Motorized Traversing Unit (BPMTU) which uses a joystick to traverse the turret. Use of the joystick distracts the gunner and prevents the gunner from continuously engaging the target while rotating the turret. This paper presents a modification to the weapon mount that allows the turret to be controlled by the position of the weapon itself and emphasizes the design process used to develop the inovation. With this design, the gunner can now maintain contact with a target, while rotating the turret, without fiddling with the joystick. The Weapon Activated and Controlled Turret (WACT) consists of two primary components; the bottom component is stationary relative to the turret and contains a Hall effect sensor and the top component rotates with the weapon and holds a linear magnet. As the position of the sensor relative to the magnet changes, the corresponding strength of the magnetic field also varies. This change in magnetic force induces a similar response in the output voltage of the Hall effect sensor, effectively translating rotational motion into an electric signal able to control the turret motor.


Author(s):  
Georgios Tsakyridis ◽  
Nikolaos I. Xiros ◽  
Michael M. Bernitsas

Magnetic levitation (maglev) concepts are applied to a variety of industries such as the automotive, aerospace, or energy in order to accomplish different tasks: suspension and propulsion in maglev trains, rocket propulsion and spacecraft attitude control, centrifuge of nuclear reactors. In this paper, maglev is implemented in environmentally friendly hydrokinetic energy harvesting to achieve contactless bearing, thus, minimizing friction and improving efficiency. Generally, maglev systems exhibit higher efficiency and reduced maintenance while providing longer lifetime and higher durability when appropriate engineering design and control are applied. A Flow Induced Oscillation (FIO) energy-harvesting converter is considered in this work. To minimize friction in the support of the cylinder in FIO (vortex induced vibrations and galloping) due to high hydrodynamic drag, a maglev system is proposed. In the proposed configuration, a ferromagnetic core (element 1), of known dimensions, is considered under the effects of an externally imposed magnetic field. A second ferromagnetic element, of smaller dimensions, is then placed adjacent to the previous considered core. This particular configuration results in a non-homogenous magnetic field for element 1, caused by dimensional disparity. Specifically, the magnetic flux does not follow a linear path from the ferromagnetic core to element 2. A general electromagnetic analysis is conducted to derive an analytical form for the magnetic field of element 1. Subsequent numerical simulation validates the obtained formula. This distinct expression for the magnetic field is valuable towards calculating the magnetic energy of this specific configuration, which is essential to the design of the FIO energy harvesting converter considered in this work.


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