• Journal of Biosystems Engineering
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• 제6권1호
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• pp.48-59
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• 1981

The major limiting factor on the determination of combine capacity is the frequent occurence of clogging over the some parts of machine when the crop is wet in the case of Japanese self-feeding type combine. And in the case of American conventional combine having big separating parts, the great grain loss and damage occur when the machine is used for rice harvesting. This experiment was carried out to develop the new type threshing and separating equipment. Proto-type thresher which consist of a conical threshing drum and a conical separating sieve rotating around the threshing cone was constructed and tested. In the case of 800 rpm of threshing cone speed, average threshing loss was below 1 percent, separating loss was about 1 percent, grain damage was about 0.4 percent, and average total power required was about 2.6 PS. This design has some problems such as higher power required or wrapping problems under the conditions of feeding long damp straw. But, compared with the conventional combine or thresher, this machine certainly has some potentials for this approach to combine development. The crop feed rate must be increased through improvement of the feeding portion of the threshing cone. And it is required to investigate further about some parameters causing wrapping phenomena.

• Journal of Biosystems Engineering
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• 제6권2호
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• pp.33-47
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• 1982

To modernize the conventional rice post production technology and reduce grain losses, a transition toward the wet-paddy threshing system has been strongly demanded. The head-feeding type thresher with pneumatic separation has been used dominantly for threshing dried-paddy, but some adverse effects in separation performance for threshing wet-paddy is encounterred. In order to solve the problems, the development of thresher with an additional oscillating sieve to the conventional pneumatic separation has been recommanded. This study was intended to evaluate the separating performance of thresher with oscillating sieve which was attached additionally to the conventional auto-thresher equipped with separation system of blower and suction fan. For different feed rates and rice varieties, wet-and dry-material were tested with threshers attached with and without oscillating sieve. Results of the study are summarized as follows: 1. When the feed rates were 480 and 640 kg/hr, there was no statistically significant difference in power reqirements between the threshers with and without an additional sieve device for both dry-and wet-threshing. However, when the feed rate was 960 kg/hr, power requirements of thresher without sieve were greater for wet-paddy threshing than the thresher with the additional sieve separator by about 20% points. 2. With additional oscillating sieve device, the ratios of total weights of whole grains including grains with branch let and damaged grains to the total output did not show statistical difference among the feed rates. However, with pneumatic separation the ratio was decreased as the level of feed rate increased. 3. The total amount of grains with branchlet (including broken panicle) increased with the moisture content. For both the wet-and dry-material threshing with the additional oscillating sieve, the percent of grains with branchlet to the total output decreased greatly as the feed rate increased. 4. The output of the damaged grains increased as moisture content decreased. Especially, for the dry-paddy threshing, the additional sieve separating device produced more damaged grains than the pneumatic separation at all feed rates. 5. Generally, for dry paddy threshing, the separating performance of the thresher with the additional sieve device was better at all feed rates, showing greater difference with increasing feed rates. 6. Separating losses were greater with the pneumatic than sieve separation for both the wet-and dry-threshing. 7. The overall comparison of separating performance of threshers tested with and without an additional sieve device showed that the former was more effective than the latter for the dry-material threshing. However, for the wet-paddy threshing, the separation performance with a sieve device was better than the pneumatic only when the feed rate was high.

• 동력기계공학회지
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• 제19권4호
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• pp.5-10
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• 2015

Dust collector is one of the most widely used equipment among the method of separating particles, it filters exhaust gas having various kinds of dusts through several filters installed on parallel. This research investigated the moving characteristic of Honeycomb-type carbon filter in pressure drop of smoking collector's ventilation system. It also compared pressure transmission coefficient through pressure drop according to flow velocity change.

• 동력기계공학회지
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• 제5권1호
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• pp.64-72
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• 2001

According to the regulation of IMO, oil discharge from ships is allowed under 15ppm only and an oil filtering equipment is essential. However, for large ships using heavy fuel oil of over S.G 0.98 and viscosity 380cSt and system oil, it has been in difficulty to process with existing filtering type of oily water separator. A parallel plate type oily water separator which is one of gravity type separators can be used as an assistant equipment for the oil filtering system to meet the present IMO standard of 15 ppm, because it is an efficient method in dealing with a large amount of rich oil with high specific gravity. This work is focused on the fundamental investigation of the performance of the plate type oily water separator by visualization method and PIV(Particle Image Velocimetry) measurement to acquire multi-point velocity data simultaneously. The experimental results showed that the space of the plates acts a significant role in separating process and it was found that an important point to minimize a vortex flow is to flow a large amount of fluid in space of the plates in order to promote the efficiency of separation.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.256-261
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• 2017

This paper deals with the experimental evaluation on power loss of a double-side permanent magnet synchronous motor/generator (DPMSM/G) applied to a flywheel energy storage system (FESS). Power loss is one of the most important problems in the FESS, which supplies the electrical energy from the mechanical rotation energy, because the power loss decreases the efficiency of energy storage and conversion of capability FESS. In this paper, the power losses of coreless DPMSM/G are separated by the mechanical and rotor eddy current losses in each operating mode. Moreover, the rotor eddy current loss is calculated by the 3-D finite element analysis (FEA) method. The analysis result is validated by separating the power loss as electromagnetic loss and mechanical loss by a spin up/down test.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.208-220
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• 2017

This paper proposes an experimental optimization method for a wireless power transfer (WPT) system. The power transfer characteristics of a WPT system with arbitrary loads and various types of coupling and compensation networks can be extracted by frequency domain measurements. The various performance parameters of the WPT system, such as input real/imaginary/apparent power, power factor, efficiency, output power and voltage gain, can be accurately extracted in a frequency domain by a single passive measurement. Subsequently, the design parameters can be efficiently tuned by separating the overall design steps into two parts. The extracted performance parameters of the WPT system were validated with time-domain experiments.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2319-2328
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• 2018

This paper introduces a control method for a transformerless MMC-HVDC system. The proposed method can effectively control the grid currents of the MMC-HVDC system under unbalanced grid conditions such as a single line-to-ground fault. The proposed method controls the currents of the positive sequence component and the negative sequence component without separating algorithms. Therefore, complicated calculations for extracting the positive sequence and the negative sequence component are not required. In addition, a control method to regulate a zero sequence component current under unbalanced grid conditions in the transformerless MMC-HVDC system is also proposed. The validity of the proposed method is verified through PSCAD/EMTDC simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.15-16
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• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• Journal of Advanced Marine Engineering and Technology
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• 제16권5호
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• pp.85-96
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• 1992

Engine enclosures are widely adopted to reduce the noise emission in various fields of application. The radiated noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound power with different path of propagation. One is the 'structure-borne sound power' which stems from the engine's vibratory force applied to the structure of enclosure through the mounting parts of engine etc., while the other is the 'air-borne sound power' which is originated by the sound power radiated from the engine surface to the inner space of enclosure that should excite the vibration of enclosure from inside. In order to get a most efficient engine enclosure is required a profound consideration upon the above structure-borne and air-borne noise, since the guiding principle of countermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subject for the structure-borne sound power and the specifications of absorbing member and damping panels are the major interests for the air-borne sound power. Hence it seems very efficient to separate the total sound power into two categories with a great accuracy when one think of further reduction of engine noise from the exciting enclosure, however, its separating methods have not been made clear for many years. Then author proposes a new practical separation method of two propagation path's contribution to the total radiation sound power for the enclosure under the engine operating condition.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.213-214
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• 2010

The Arc fault is primary reason of electric fire. so we must detect. the purpose of this study is to extend our knowledge of AC-arc characteristics and detect. The Arcs are produced by separating two electrodes made with graphite and copper. A very low separation speed allows arcs to reinitiate, as in arc fault in wires. Power is 220Vrms-60Hz and the load is light bulbs and capacities are 220W, 660W and 1100W. I measured Arc voltage and current. and defined voltage and current Max level, voltage plateau and Arc-power at each cycle.