• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.241-243
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• 1996

This papar presents an analysing method of radial force densities acting on each stator tooth of an induction motor with skewed slots. Two-dimensional finite element method is used for electromagnetic Held analysis of an induction motor, and skew effects are considered by coupling several disks cut by planes perpendicular to the shaft. Radial force densities as a source of vibration are calculated along the surface elements of each stator tooth and its time harmonics are examined by discrete Fourier decomposition.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.157-162
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• 2000

The ball bearings are the widely-used machine elements in many machineries. They support not only the radial and the axial force but also the moment in many cases. To simply determine the limit load which can be maintained on an ball bearing or survived in wanted life, the combined the radial and axial force with the moment is converted to the equivalent radial or axial load. However, it is not easy to calculate the equivalent load on the ball bearings. So the simplified equations to evaluate the dynamic and static equivalent load considering the axial force and moment are proposed in this analysis. And the modified equation for the static equivalent radial load with the moment and the axial load is proposed. It is desired that these equations are effectively refered in designing the machineries where the ball bearings are installed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.281-282
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• 2002

To reduce the spin-off of lubricants on a magnetic disk, which is caused by the radial component of shear force between the disk and air, we analyzed the air-velocity distribution and the air-shear force by three-dimensional large-eddy simulation (LES). This sensitivity analysis, on five design parameters, showed that disk/arm clearance and arm thickness have a greater effect on the mean radial air-shear force than the other parameters. The force on a disk optimized according to the optimum parameters is 12% less than the force on a conventional disk.

• Journal of Advanced Marine Engineering and Technology
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• v.7 no.2
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• pp.22-28
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• 1983

In former papers which were published already, authors had derived calculation formulae for the axial stiffness and the radial force conversion factor of crankshaft. In this paper, crankthrow axial stiffness and radial force conversion factors of actual engines are calculated by these theoretical formulae and then their characteristics are investigated. As the results, the axial stiffness and the radial force conversion factor of the latest super-long stroke engine are smaller than those of old-type engines. The influence of the former brings down the resonance speed of engine and the latter reduces the exciting force of axial vibration, but as the harmonic component of axial vibration force becomes rather strong, its effect of reducing is considerably canceled. In conclusion, as the latest super-long stroke engine is seemed to be liable to axial vibration of crankshafat, it is recommend that, in the design stage of propulsion shaft, its axial vibration condition must be more carefully checked.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.482-487
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• 2001

This paper introduces a Lorentz force type four-pole self-bearing motor, where the new pole arrangement of a stator is intended to function both as a synchronous PM motor and as a magnetic bearing. The Lorentz force type has some good points such as linearity of control force, freedom from flux saturation, and high efficiency unlike conventional self-bearing motors. Mathematical expressions of torque and radial force are derived to show that they can be separately controlled regardless of rotational speed and time. To verify the proposed theory, a prototype is made, where a ring-shape outer is actively controlled in two radial directions while the other motions are passively stable supposing the radial stability. Through some experiments, it is shown that the proposed scheme can provide high capability and feasibility for a small high-speed self-bearing motor.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.96-100
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• 2007

Condenser lens and objective lens are used to demagnify the image of the crossover to the final spot size. In lens, electrons are focused by magnetic fields. This fields is fringing field. It is important in electron focusing. Electron focusing occurs the radial component field and axial component field. Radial component produces rotational force and axial component produces radial force. Radial force causes the electron's trajectory to curve toward the optic axis and corss it. Focal length decreases as the current of lens increases. In this paper, we use the focal length for desiging the hardware of lens current control and present the results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.11
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• pp.548-556
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• 2003

Switched reluctance motor(SRM) has simple magnetic structure, and needs simple power electronic driving circuit. It is very useful for wide range adjustable speed drive system. But, SRM drive generates large vibration and acoustic noise because it is commutated individually by step pulse m.m.f of each phase. In the vibration and acoustic noise characteristics. the considerable vibration and noise is induced by radial deforming of stator, so the frequency of dominant vibration and noise is coincident with the frequency of natural frequency of mechanical structure. This radial vibration force is generated by abrupt change of radial magnetic force in the phase commutation region. This paper studied about simple electromagnetic structure of SRM using auxiliary compensating winding for the reduction of noise and vibration. This auxiliary winding is coupled with all phase windings electromagnetically and absorb and transfer magnetic energy variation from phase to other phase. By this interaction of phase windings and compensating winding can reduce abrupt radial force change and vibration and acoustic noise. In this paper the improvement effect is examined by the test of prototype machine.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.557-566
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• 1991

The metal V-belt behavior of a continuously variable transmission was investigated analytically and experimentally. Numerical results showed that nondimensional belt radial displacement increased in the radial inward direction for the driven pulley, while that of the driver pulley increased for the first 90 degrees of the active are and decreased with the increasing torque load. Experimental results for the belt radial displacement were in good agreement with the theoretical results. However, the absolute magnitude of the belt radial displacement was so small that the change in the belt displacement could not be measured in the experimental range except for the inlet region of the driven pulley, where the radial inward displacement was observed due to the effect of bending moment. The speed ratio-axial force relationship derived from the belt behavior analysis also showed god agreement with the experiment.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.888-892
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• 2014

In the design of the rotor of an interior permanent magnet synchronous motor (IPMSM), the bridge between the permanent magnets helps prevent the scattering of permanent magnets and pole pieces during high-speed operation. In the design of a motor, if the bridge is too thick, its performance will be largely degraded because of flux leakage. Additionally, if the bridge is too thin, its mechanical safety cannot be guaranteed. Thus, an accurate analysis method is required to determine the thickness of the bridge. Conventional stress analysis methods determine the thickness of the bridge by only considering the centrifugal force of the rotors. In this study, however, a method that additionally considers the radial force generated by the air-gap flux density based on the conventional methods is proposed and reflected in the design of a traction motor for electric vehicles. Finally, the validity of this study is verified through a reliability test related to high-speed operation.

• Proceedings of the Korean Magnestics Society Conference
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• 1998.10a
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• pp.122-123
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• 1998