• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.10
• /
• pp.21-26
• /
• 2016

This study evaluates the magnitudes and distributions of contact tangential forces with the swaging depth of punch acting at the contact surfaces between a rotor core slot and a Cu bar during a sequential rotor core swaging process. The effects of the core slot shape on the magnitudes and distributions of the total contact forces were investigated to improve the productivity of the rotor core swaging process. Parametric elastic-plastic numerical analyses were performed using simplified two-dimensional cyclic symmetric plane strain models to evaluate the contact force distributions at the contact surfaces. The numerical analysis results show that the total contact tangential forces increased by about 55% with the adjacent Cu bar swaging process. The length of the core slot is a dominant factor in the core slot design as result of the increased total contact tangential forces during the swaging process of the rotor core.

• Journal of Korea Foundry Society
• /
• v.36 no.1
• /
• pp.10-17
• /
• 2016

Numerical analysis has been performed to evaluate effect of the shape variables such as core length, slot width and slot length on misrun in aluminum die casting process for motor rotor. The predictive method for misrun in diecasting process was established by comparing the result of numerical analysis and an actual motor rotor. Solidification modulus was introduced to predict quantitatively the castability of aluminum diecasting process for motor rotor. It was found that there are minimum critical solidification modulus and slot width to prevent misrun according to core length through diecasting limit diagram proposed using the predictive method. The critical solidification modulus and slot width increase as core length increases to prevent misrun of aluminum motor rotor in diecasting process. Based on the results, the design criteria of slot shape to prevent misrun of aluminum motor rotor with various core length were established.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.251-254
• /
• 2003

In this study, main works are focused on investigating the stress distribution at the interface between a rotor core and Cu bar when a punch is applied into the body of Cu bar. A parametric study with dimensional changes of core slot was performed numerically to identify what factors are dominant in producing high contact forces in the interface. As analysis results, it was found that core slot length was a dominant factor in increasing contact force at the interface between a rotor core and Cu bar.

• Proceedings of the KIEE Conference
• /
• 2004.04a
• /
• pp.86-88
• /
• 2004

In this paper, optimal stator slot shape of 3-phase inverter-fed induction motor is designed to reduce stator core and winding losses. For the analysis, the F.E.M on 1 phase band periodic condition in stator is coupled with harmonic equivalent circuit. For the optimal design, the conjugate gradient method is used as an optimizing algorithm. The stator core and winding losses are reduced by the design method. The results are verified by those of the time-step finite element analysis.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.771-772
• /
• 2006

Recently, Interior Permanent Magnet Synchronous Motor(IPMSM) is widely used in the industry applications such as power train for hybrid vehicles and compressor motors of air-conditioner due to its high power density and wide speed range. In designing motors, pole slot combination should be chosen properly according to the use of the motor and driving method in the initial design stage, accordingly there have been many researches about pole slot combination. As a part of the studies, this paper presents a comparison of characteristics of concentrated winding IPMSM, such as back-emf, Total Harmonic Distortion(THD) and core losses for each pole slot combination. By comparing the characteristics of each model, this paper can be a guide or reference in determining pole slot combination in the initial design stage.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.4
• /
• pp.589-595
• /
• 2008

Detent force of a permanent magnet linear motor(PMLSM) consist of cogging and drag forces, and should be minimized for high precision control purpose applications. This paper shows that the cogging force can be reduced effectively by employing 9 pole 10 slot structure. The drag force is minimized by optimizing the total length and shape of the exterior teeth of armature core simultaneously by using($1+{\lambda}$) evolution strategy coupled with response surface method. After optimization, the optimized PMLSM is proven to reduce 95% and 92.6% of the cogging and total detent forces, respectively, and give 12% and 6.4% higher Back-emf and thrust force, respectively, compared with a conventional 12 pole 9 slot structure under the same condition. Additionally, Simulation results by the proposed optimum design are verified by the experiment results.

• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.187-194
• /
• 2010

Shape optimization of an upper plenum of PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of eight of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.

• Journal of computational fluids engineering
• /
• v.15 no.3
• /
• pp.16-23
• /
• 2010

Shape optimization of an upper plenum of a PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of height of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.3
• /
• pp.313-320
• /
• 2013

The fractional slot windings are widely used in rotating machine in order to increase the flexibility of design and improve the voltage waveform. However, the MMF wave of fractional-slot windings are found to contain unique harmonic component, which are designated as even order space flux harmonics, fractional number flux harmonics, or both. They may cause stray loss and stator core vibration. This paper proposes new winding methods "novel interspersed windings" and "expanded group windings" to reduce these harmonics. The advantages of two proposed windings are verified by using numerical analysis and measurement test of winding model.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.929-931
• /
• 1993

The design sensitivity analysis based on the finite element method is presented for the eddy current problem with a voltage source. Since, in this problem, the complex variable is used as the state variable, new approach to the sensitivity calculation for the complex variable system is required. Its result is applied to the design of the rotor slot shape of squirrel cage induction motor. As a analysis model, only one slot pitch of rotor is analyzed by using a Periodic boundary condition. The use of this minimal modelling method leads to much saving of calculation time. The design objective is to obtain the desired slip-torque characteristic. Because the shape of rotor slot has much influence on the slip torque characteristic, the design variables are taken on the interface shape between rotor core and rotor bar. The initial shape of rotor slot is the trapezoidal type with rounding corners. The obtained final shape is quite similar to the double squirrel cage type.