• Journal of Veterinary Clinics
• /
• v.16 no.2
• /
• pp.409-412
• /
• 1999

To establish the electroacupuncture anesthesia for pigs, 6 piglets (Landrace mixed, 1 month old, 3.7~5.3 kg, female: 3 heads and male: 3 heads) were examined. The acupoints used for porcine electroacupuncture anesthesia were An-shen, and Tian-ping and Bai-hui. After horizontal insertion of needle to left and right An-shen, and perpendicular insertion to Tian-ping and Bai-hui, respectively, positive electrode was connected at right An-shen and Tian-ping, and negative electrode was connected at left An-shen and Bai-hui using veterinary electroacupuncture anesthesia apparatus, respectively. Electric condition was 3 V and 30 Hz. To examine the effect of electroacupuncture anesthesia, laparotomy (4 heads) and castration (2 heads)were applied. The induction time of electroacupuncture anesthesia was very rapid and about 1 minute, and pain of the body surface including the extremities was not detected. As for the reactions with electroacupuncture anesthesia, the head was directed to backward, nasal part was curved to one side, and blepharum was closed in part of changed nasal part. In addition, consciousness was vivid, and muscle tension and lift of the tail were observed in early stage but was relaxated afterwards. The pain was not found during incision and suture, bleeding was comparatively small volume and the class of anesthesia effect was excellent.

• Journal of Veterinary Clinics
• /
• v.16 no.2
• /
• pp.417-421
• /
• 1999

To establish the electroacupuncture anesthesia for experimental animal, 5 adult rabbits (Newzealand-white species) and 6 rats (Spraque-dawley) were examined. The acupoints used for electroacupuncture anesthesia were Tian-ping and Bai-hui. After perpendicular insertion of needle to the acupoints, positive electrode was connected at Tian-ping and negative electrode was connected at Bai-hui using veterinary electroacupuncture anesthesia apparatus, respectively. Electric conditions were 2~3 V and 30 Hz in rabbits, and 1.5~2 V and 30 Hz in rats, respectively. To examine the effect of electroacupuncture anesthesia, laparotomy (2 heads), castration (2 heads) and ovariohysterectomy (1 head) were applied in rabbits, and laparotomy (5 heads) and castration (1 head) were peformed in rats, respectively. The induction time of electroacupuncture anesthesia was very rapid and approximately 1 minute, and pain of body surface including the extremities was not detected in rabbits and rats. As for the reactions with electroacupuncture anesthesia, consciousness was vivid, blepharoreaction was not observed and the tail was up at early stage but was down afterwards in rabbits. The same findings except cotinuous lifting of the tail were observed in rats. The pain was not observed during incision and suture, bleeding was comparatively small volume and the class of anesthesia effect was excellent.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.12
• /
• pp.777-784
• /
• 1999

Since the ultra-high voltage power apparatus are recommended to withstand switching surge generated from the electric power system, the switching impulse voltage is generally used to verify this requirement at the testing laboratories. Recently, the international standard(IEC 60060-2) related to the high voltage measurement techniques is revised requiring a traceability of measuring system for high voltage measurements. In this paper, a reference divider for switching impulse voltage is developed satisfying the revised. IEC standard and the possibility of applications has been investigated. Therefore, the characteristics of the high and low voltage side resistor and the shielding ring have been analyzed including the step response characteristics of the prototype divider. Throughout various efforts, it is confirmed that our measuring device has shown compatible characteristics as a reference divider.

• Fire Science and Engineering
• /
• v.12 no.4
• /
• pp.13-19
• /
• 1998

We investigated the weight loss according to temperature using Thermal Gravimetric Analysis(TGA) in order to find the thermal hazard of carbon black(Hi-Black 10, Hi-Black 50L) dusts, and the properties of dust explosion in variation of the surface functional groups and specific surface area of their dust with the same particle size. Using Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after making dust disperse by compressed air, dust explosion experiments have been conducted by varying concentration and size of carbon black dust. The explosion pressure of both carbon black increased as the specific surface area increased. The results indicated that Hi-Block 50L of which specific surface area was larger three to four times than that of Hi-Black 10 was much easier of dust explosion.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1895-1897
• /
• 1996

Lightning impulse voltage is essential to evaluate the insulation performance of electric power apparatus. Recently international standard (IEC-60) on high voltage measurement techniques are being revised. In the draft of this standard, a new calibration method is introduced and the accuracy of most industrial measuring systems is maintained by means of comparison test against the reference measuring systems. Comparison tests of dividers for chopped lightning impulse measurement were rallied out by KERI. The 700kV shielded resisitive divider with and without compensation element were done comparison test with 300kV PTB divider which have the similar charateristics as that were circulated among the laboratories. This paper reports on the calculation results of response charateristics obtained by EMTP and the comparison test results with chopped lightning impulse voltages from 150kV to 250kV. It is demonstrated that KERI are capable of realizing the idea in the revision of the IEC standand, that is, to establish traceability.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.983-989
• /
• 2015

Power transformer is one of the major and key apparatus in electric power system. Monitoring and diagnosis of transformer fault is necessary for improving the life period of transformer. The failures caused by short circuits are one of the causes of transformer outages. The short circuit currents induce excessive forces in the transformer windings which result in winding deformation affecting the mechanical and electrical characteristics of the winding. In the present work, a transformer producing only the radial flux under short circuit is considered. The corresponding axial displacement profile of the windings is computed using Finite Element Method based transient structural analysis and thus obtained displacements are compared with the experimental result. The change in inter disc capacitance and mutual inductance of the deformed windings due to different short circuit currents are computed using Finite Element Method based field analyses and the corresponding Sweep Frequency Responses are computed using the modified electrical equivalent circuit. From the change in the first resonant frequency, the winding movement can be quantified which will be useful for estimating the mechanical withstand capability of the winding for different short circuit currents in the design stage itself.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1181-1187
• /
• 2015

Sulfur hexafluoride (SF₆) gas is used widely in electric power equipment such as Gas Insulated Switchgear (GIS), Gas Insulation transmission Line (GIL), and Gas Circuit Breaker (GCB). But applications of SF₆ should be restricted because SF6 gas is one of the greenhouse effect gases. To reduce use of SF₆ gas, a study on eco-friendly alternative insulation medium is needed. In this paper, we investigated lightning impulse (LI) breakdown of dry-air which is attracting attention as an ecofriendly alternative gas and the LI breakdown of hybrid insulation combined with dry-air and solid insulation (Room-Temperature Vulcanizing Silicone Rubber-RTV SIR) and dry-air in inhomogeneous fields according to gap distance and pressure. The experiment results showed that the LI breakdown strength of hybrid insulation system was higher than that of dry-air insulation system. It was verified that the development of technology related to eco-friendly power apparatus compact such GIS, GCB and GIL can be used as basic research data.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1403-1406
• /
• 2002

Environmental impact of human activities has become a great concern in most of the countries world-wide, and for years. It has recently focused on potential climate changes due to the increase of green house gases content in the atmosphere. One of these gases is $SF_6$, which is an essential material in electrical applications having excellent dielectric and arc-quenching properties. Though the actual contribution of $SF_6$ to global warming is negligible at present, the control of $SF_6$ emissions seems to be nevertheless imperative. Actually, it is listed in the Kyoto protocol that emissions should not only be duly reported but also the electrical industry which is now the major user of this gas must be able to show that it is possible to use this gas and at the same time preserve the environment. For the development of environmentally-benign electric power equipment and systems, novel gases or gas mixtures are strongly required as the alternatives of $SF_6$ gas. Until now, most research work is focused on the $SF_6/N_2$ mixed gas which is suitable for application in the electrical apparatus with slightly non-uniform fields. Recently, $SF_6/CO_2$ mixed gas also is expected to be promising as a $SF_6$ alternative, especially in highly non-uniform fields and in a gas-impregnated film insulation system. Including these results, the author reviews the research trend or reducing the environmental impact of $SF_6$ gas in this paper.

• The KSFM Journal of Fluid Machinery
• /
• v.17 no.2
• /
• pp.48-53
• /
• 2014

A low-noise regenerative blower is developed for fuel cell application by combining the FANDAS-Regen code and design optimization algorithm under several performance constraints for flow capacity, static pressure, efficiency and power consumption. The optimized blower design model is manufactured with some impeller modification based on low noise design concept and tested by using aerodynamic performance chamber facility and narrow-band noise measurement apparatus. The measured results of the optimized blower satisfy the performance requirements and are also compared favorably with the FANDAS-Regen prediction results within a few percent relative error. Furthermore, the present study shows the remarkable noise reduction by 26 dBA can be achieved through design optimization and low noise design concept.

• Journal of Veterinary Clinics
• /
• v.18 no.4
• /
• pp.311-314
• /
• 2001

To elucidate the effect of dorsal acupoints for canine electroacupuncture anesthesia, mongrel dogs(6 heads: 2.6-10.5kg, 3 males and 3 females) were used. After needling perpendicularly to Tian-Ping(GV-5) and Bai-Hui(GV-20), the electrodes were connected with positive to Tian-Ping and negative to Bi-hui, respectively using with veterinary electroacupuncture apparatus(TEC AM-3000). The electric conditions were 2-4V and 30 Hz. The pain of body surface was checked by hemostatic forceps. The effect of electroacupuncture andesthesia was appreciated by application of laparotomy(2 heads), ear trimming and tail amputation(1 head), castration(2 heads) and enterotomy(1 head), respectively. Induction time, clinical findings and operation findings were investigated under the electroacupuncture anesthesia. The induction time of electroacupuncture anesthesia was very rapid, approximately 1 minute and the pain of body surface including the extremities was not detected. As for clinical findings during electroacupuncture anesthesia, consciousness was evident, pupil reflex was weak and blepharoreaction was existed. As for operation findings, pain was not detected during incision and suture, and bleeding was relatively small volume. The grade of electroacupuncture anesthesia was excellent in all cases applied with ear trimming and tail amputation, laparatomy, castration and enterotomy. Considering above all findings, it was thought that electroacupuncture stimulation at Tian-Ping and Bai-hui examined in the present study induced excellent electroacupuncture anesthesia for dogs.