Stator Design of Alternate Slot Winding for Reducing Torque Pulsation With Magnet Designs in Surface-Mounted Permanent Magnet Motors

This paper proposes a stator design that consists of a combination of an alternate slot winding and dummy slots to minimize pulsating torque in surface-mounted permanent magnet synchronous motors. The alternate arrangement of winding coils is designed to eliminate a harmonic component of back electromotive force that gives rise to a harmonic component of pulsating torque. However, the non-uniform arrangement of slots decreases the frequency of the cogging torque by half and may aggravate torque pulsation. To compensate for the drawback or the decrease in the frequency of the cogging torque, dummy slots are introduced in the alternately slotted stator. A theoretical method is developed for the proposed stator combination. The proposed stator design is applied to a prototype in combination with other rotor magnet design techniques, such as magnet shifting and the adjustment of magnet width, to minimize pulsating torque. The results show that the designed motor reduces the ripple factor of the torque by approximately 30% relative to the original value. In addition, the proposed alternate slot winding is validated by comparing the design with equal slot-winding designs optimized through finite-element method analysis

Performance of segment type switched reluctance motor using grain-oriented

Authors developed a segment type switched reluctance motor (SRM) as a rare earth less motor. The object is to reduce the acoustic noise and vibration as well as improve the torque characteristics. In this paper, we propose the performance improve method using grain-oriented electric steel as the segment core. The validity is confirmed experimentally.15th International Conference on Electrical Machines and Systems, ICEMS 2012; Sapporo; Japan; 21 October 2012 ～ 24 October 201

A Sexually Conditioned Switch of Chemosensory Behavior in C. elegans

In sexually reproducing animals, mating is essential for transmitting genetic information to the next generation and therefore animals have evolved mechanisms for optimizing the chance of successful mate location. In the soil nematode C. elegans, males approach hermaphrodites via the ascaroside pheromones, recognize hermaphrodites when their tails contact the hermaphrodites' body, and eventually mate with them. These processes are mediated by sensory signals specialized for sexual communication, but other mechanisms may also be used to optimize mate location. Here we describe associative learning whereby males use sodium chloride as a cue for hermaphrodite location. Both males and hermaphrodites normally avoid sodium chloride after associative conditioning with salt and starvation. However, we found that males become attracted to sodium chloride after conditioning with salt and starvation if hermaphrodites are present during conditioning. For this conditioning, which we call sexual conditioning, hermaphrodites are detected by males through pheromonal signaling and additional cue(s). Sex transformation experiments suggest that neuronal sex of males is essential for sexual conditioning. Altogether, these results suggest that C. elegans males integrate environmental, internal and social signals to determine the optimal strategy for mate location

A characteristic experiment of 4-phase segment type switched reluctance motor

Authors developed a novel segment type switched reluctance motor (SRM) as a rare earth less motor. The torque was increased by 40% and the radial force was decreased by 76% compared with the same size VR type SRM. Increasing the average torque, however, caused increasing torque ripple. In this paper we propose a 4-phase segment type switched reluctance motor and show that the torque ripple can be decreased by controlling the excitation current.15th International Conference on Electrical Machines and Systems, ICEMS 2012; Sapporo; Japan; 21 October 2012 ～ 24 October 201

On the improvement performance of a dual rotor segment type SRM

A dual rotor segment type switched reluctance motor (SRM) is proposed for flat configuration. It has toroidal stator coil and has inner rotor as well as outer rotor. The performance characteristics are calculated using finite element method. On a flat type SRM, leakage flux is greatly generated at both side coil. To reduce the leakage flux we propose shield structure. Effectiveness of the shield structure is verified analytically.2013 IEEE 10th International Conference on Power Electronics and Drive Systems, PEDS 2013; Kitakyushu; Japan; 22 April 2013 through 25 April 201

Characteristics of a half-wave rectified brushless synchronous generator

The paper proposes the half-wave rectified brushless synchronous generator and analyzes the basic characteristics using the finite element method. It is based on the half-wave rectified excitation theory and doesn\u27t need brush and slip ring system or permanent magnets for field excitation.7th International Power Electronics Conference, IPEC-Hiroshima - ECCE Asia 2014; Hiroshima; Japan; 18 May 2014 through 21 May 201

Association between tear film break up time and blink interval in visual display terminal users

AIM: To investigate the association between tear film break up time (TBUT) and blinking interval in visual display terminal (VDT) users. METHODS: Nine hundred and thirty VDT users underwent dry eye testing, and functional visual acuity (FVA) test. The blinking interval during FVA was compared with TBUT. Subjects with longer blinking interval than TBUT were considered as unstable tear film. Logistic regression analysis revealed the risk factors for unstable tear group. RESULTS: Among 930 workers, 858 subjects (92.3%) participated in this study. Almost 80% of the subjects were categorized into the unstable tear group. Unstable tear group has significantly lower Schirmer values and TBUT (17.5±11.6 vs 21.1±11.5 mm, 3.7±2.6 vs 5.7±2.7s, both P<0.001). There were no significant differences in epithelial staining or severity of symptoms. Logistic regression showed that over 40y was a risk for being unstable tear group [odds ratio (OR)=1.53; 95% confidence interval (CI)=1.06-2.20]. Contact lens use was protective factor for being in the unstable tear group (OR=0.37; 95%CI= 0.26-0.53). CONCLUSION: Subjects with shorter TBUT than blinking interval are prevalent among VDT users. Subjects over the age of 40 shows an increased risk for unstable tear film

Rotor design of a novel self-start type permanent magnet synchronous motor

Recently, permanent magnet type synchronous motor has been used widely for industry application. In the paper, we propose a novel self-start type permanent magnet synchronous motor with squirrel-cage and analyze the basic characteristics of the motor. We try to increase the efficiency by the rotor design with the finite element analysis.15th International Conference on Electrical Machines and Systems, ICEMS 2012; Sapporo; Japan; 21 October 2012 ～ 24 October 201

Antiplatelet antibody may cause delayed transfusion-related acute lung injury

A 61-year-old woman with lung cancer developed delayed transfusion-related acute lung injury (TRALI) syndrome after transfusion of plasma- and leukoreduced red blood cells (RBCs) for gastrointestinal bleeding due to intestinal metastasis. Acute lung injury (ALI) recurred 31 days after the first ALI episode. Both ALI episodes occurred 48 hours after transfusion. Laboratory examinations revealed the presence of various antileukocyte antibodies including antiplatelet antibody in the recipient’s serum but not in the donors’ serum. The authors speculate that antiplatelet antibodies can have an inhibitory effect in the recipient, which can modulate the bona fide procedure of ALI and lead to a delay in the onset of ALI. This case illustrates the crucial role of a recipient’s platelets in the development of TRALI