• Title/Summary/Keyword: motors

Search Result 3,621, Processing Time 0.03 seconds

Classification of Vibration Signals for Different Types of Failures in Electric Propulsion Motors for Ships Using Data from Small-Scale Apparatus (소형 모사 장비의 데이터를 이용한 선박용 전기 추진 모터의 고장 유형별 진동 신호의 분류)

  • Seung-Yeol Yoo;Jun-Gyo Jang;Min-Sung Jeon;Jae-Chul Lee;Dong-Hoon Kang;Soon-Sup Lee
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.60 no.6
    • /
    • pp.441-449
    • /
    • 2023
  • With the enforcement of environmental regulations by the International Maritime Organization, the market for eco-friendly ships is expanding, and ships using electric propulsion devices are emerging as a promising solution. Many studies have been conducted to predict the failure of ships, but most of them are mainly research on the main diesel engine of ships. As the ship's propulsion method changes, new data is needed to predict the failure of electric propulsion ships. In this paper aims to analyze the failure characteristics of the electric propulsion system in consideration of the difference in the type of failure between the internal diesel engine and the electric propulsion system. The ship's propulsion unit assumed a DC motor and a signal pattern for normal conditions and general failure modes, but the failure record of the electric propulsion device operated on the actual ship was not available, so it generated a failure signal for small electric motor equipment to identify the failure signal. Assuming unbalance, misalignment, and bearing failure, which are the primary failure modes of the ship's electric motor, a failure signal was generated using a "rotator vibration data generator," and the frequency band, size, and phase difference of the measured vibration signal were analyzed to analyze the characteristics of each failure condition. Finally, the characteristics of each failure condition were identified so that the signals according to the failure type could be classified.

A Study on the Design Criteria of UAM Vertiport Complying New FAA and EASA Regulations and Its Domestic Applications (FAA와 EASA의 새 규정에 따른 UAM Vertiport 설계 기준 및 국내 적용 연구)

  • Byeong-Seon Ahn;Sung-chang Choi;Ho-Yon Hwang
    • Journal of Advanced Navigation Technology
    • /
    • v.26 no.6
    • /
    • pp.380-392
    • /
    • 2022
  • In this paper, the new vertiport regulations of the FAA and EASA are analyzed for urban air mobility(UAM), and the major components of the vertipad and the new specifications of each component are analyzed, and UAM operation in various environments is analyzed. Additional components for vertiport and regulations for surrounding airspace were also reviewed. Afterwards, based on the size of the S-A1 aircraft being developed by Hyundai Motors, domestic vertiport specifications and layouts were investigated for UAM operation, and these were applied to the city of Incheon. In addition, the time required for using a taxi or car were compared with the time required for using UAM between major locations in Incheon and Seoul.

Study on Performance of Electric Propulsion Systems for Aircraft applying Magnetic Gears (마그네틱 기어를 적용한 항공기용 전기추진 시스템의 성능 연구)

  • Sung-Hyun Lee;Rae-Eun Kim;Jung-Moo Seo
    • Journal of Aerospace System Engineering
    • /
    • v.17 no.6
    • /
    • pp.27-34
    • /
    • 2023
  • This paper presents the application of a magnetic gear to the electric propulsion system for an aircraft. Since high torque is required in aircraft electric propulsion systems, combining a speed reducer can amplify the torque. However, mechanical gears have issues, such as friction, vibration, and heat generation, which lead to maintenance challenges. In the case of a direct-drive motor that does not use mechanical gears, the size and weight of the motor increase to achieve high torque. This paper proposes the application of a magnetic gear to solve the maintenance issues of mechanical gears and the weight increase problem of direct-drive motors in aircraft electric propulsion systems. In this paper, a magnetic gear suitable for aircraft electric propulsion systems is designed, and it is compared with a direct-drive motor in terms of performance and the feasibility of applying the magnetic gear is verified.

A Study on the Controller Design of 3D Printed Robot Hand using TPU Material (TPU 소재를 이용한 3D 프린팅 로봇 손의 제어기 설계에 관한 연구)

  • Young-Rim Choi;Ye-Eun Park;Jong-Wook Kim;Sunhee Lee
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.48 no.2
    • /
    • pp.312-327
    • /
    • 2024
  • In this study, a rehabilitation 3D printed wearable device was developed by combining an assembly-type robot hand and an integral-type robot hand through fused deposition 3D printing manufacturing with various hardness TPU (Thermoplastic Polyurethane) filaments. The hardware configuration of the robot hand includes a controller designed with four motors, one small servo motor, and a circuit board. In the case of the assembly-type robot hand model, a 3D printed robot hand was assembled using samples printed with TPU of hardness 87A and 95A. It was observed that TPU with a hardness of 95A was suitable for use due to shape stability. For the integrated-type robot hand model, the external sample using TPU of hardness 95A could be modified through a cutting method, and the hardware configuration is the same as the assembly-type. The system structure of the 3D printed robot hand was improved from an individual control method to a simultaneous transmission method.Furthermore, the system architecture of an integrated 3D printed robotic hand rehabilitation device and the application of the rehabilitation device were developed.

Asymmetric Effect of Social Sentimental on an Individual Stock Price Return (소셜 감성이 개별 기업 주식수익률에 미치는 비대칭적 영향 분석)

  • Sei-Wan Kim;Jee-Won Park;Young-Min Kim;Hee Kyung Ham
    • Information Systems Review
    • /
    • v.22 no.4
    • /
    • pp.59-74
    • /
    • 2020
  • This paper investigates the asymmetric effect of social sentimental on an individual stock price return. For this purpose, four companies such as POSCO, Korean Electricity, AMORE PACIFIC, KIA Motors are chosen from KOSPI listed companies in terms of dataperspective. The main estimation results are as follows: the positive opinions affect only the stock prices return of three companies while the negative opinions affect all of the companies. It shows that positive or negative texts give asymmetric effect on stock price return and the effect of negative opinions is bigger than that of positive opinions. The results imply that investors are more sensitive to the negatives since they have the tendency of loss aversion. Also, it indicates that subjective opinion on SNS can be used as the proxy for the investment sentiment.

Implementation and Verification of Precise Lift-Cruise Dynamics Model Using Flightlab (Flightlab을 활용한 정밀 Lift-Cruise 동역학 모델 구현과 검증)

  • Chi-sung Roh;Daniel Kim
    • Journal of Advanced Navigation Technology
    • /
    • v.28 no.4
    • /
    • pp.386-392
    • /
    • 2024
  • This paper constructs a precise dynamics model using flightlab, a specialized program for rotor modeling and performance analysis, to simulate urban air mobility (UAM). flightlab is well-suited for detailed modeling of UAM, particularly requiring detailed aerodynamic characteristics under high-altitude and urban wind conditions. The study focuses on implementing and analyzing a lift-cruise UAM model with distributed propulsion using flightlab. The lift-cruise model integrates motors for vertical take-off and fixed-wing flight. Given the limited specific examples of such UAM models in flightlab and challenges in evaluating with conventional fixed-wing or drone models, this research implements and verifies the lift-cruise model using matlab, comparing its performance against flightlab results to validate the modeling approach. This research aims to explore the potential of flightlab for detailed UAM modeling and contribute to technological advancements in future urban transportation.

MULTISTEP HEAT-TREATMENT EFFECTS ON ELECTROSPUN Nd-Fe-B-O NANOFIBERS

  • EUN JU JEON;NU SI A. EOM;JIMIN LEE;BIN LEE;HYE MI CHO;JI SUN ON;YONG-HO CHOA ;BUM SUNG KIM
    • Archives of Metallurgy and Materials
    • /
    • v.63 no.3
    • /
    • pp.1433-1437
    • /
    • 2018
  • Neodymium-Iron-Boron (Nd-Fe-B) magnets are considered to have the highest energy density, and their applications include electric motors, generators, hard disc drives, and MRI. It is well known that a fiber structure with a high aspect ratio and the large specific surface area has the potential to overcome the limitations, such as inhomogeneous structures and the difficulty in alignment of easy axis, associated with such magnets obtained by conventional methods. In this work, a suitable heat-treatment procedure based on single-step and multistep treatments to synthesize sound electrospun Nd-Fe-B-O nanofibers of Φ572 nm was investigated. The single-step heat-treated (directly heat-treated at 800℃ for 2 h in air) samples disintegrated along with the residual organic compounds, whereas the multistep heat-treated (sequential three-step heat-treated including three steps;: dehydration (250℃ for 30 min in an inert atmosphere), debinding (650℃ for 30 min in air), and calcination (800℃ for 1 h in air)) fibers maintained sound fibrous morphology without any organic impurities. They could maintain such fibrous morphologies during the dehydration and debinding steps because of the relatively low internal pressures of water vapor and polymer, respectively. In addition, the NdFeO3 alloying phase was dominant in the multistep heat-treated fibers due to the removal of barriers to mass transfer in the interparticles.

Numerical Analysis of Steering Instability of 55kW Eletric Tractor by Bouncing and Sliding (Bouncing과 Sliding에 의한 55 kW급 전기 트랙터의 조향 불안정성 수치해석)

  • Yeong Su Kim;Jin Ho Son;Yu Jin Han;Seok Ho Kang;Hyung Gyu Park;Yong Gik Kim;Seung Min Woo;Yu Shin Ha
    • Journal of Drive and Control
    • /
    • v.21 no.3
    • /
    • pp.56-69
    • /
    • 2024
  • Tractors are used for farming in harsh terrain such as slopes with slippery fields and steep passages. In these potentially dangerous terrain, steering instability caused by bouncing and sliding can lead to tractor rollover accidents. The center of gravity changes as parts such as engines and transmissions used in existing internal combustion engine tractors are replaced by motors and batteries, and the risk of conduction must be newly considered accordingly. The purpose of this study was to derive the center of gravity of a 55 kW class electric tractor using an electric platform from an existing internal combustion engine tractor, and to numerically investigate the tractor steering instability due to bouncing and sliding. The analysis provides a strong analysis by integrating an elaborate combination of a bouncing model and a sliding model based on Coulomb's theory of friction. Various parameters such as tractor speed, static coefficient of friction, bump length and radius of rotation are carefully analyzed through a series of detailed designs. In particular, the simulation results show that the cornering force is significantly reduced, resulting in unintended trajectory deviations. By considering such complexity, this study aims to secure optimal performance and safety in the challenging terrain within the agricultural landscape by providing valuable insights to improve tractor safety measures.

Design of electric skateboard with gearbox (기어박스가 장착된 전동 스케이트보드 설계)

  • Sang-Hyun Kim
    • The Journal of the Convergence on Culture Technology
    • /
    • v.10 no.5
    • /
    • pp.687-692
    • /
    • 2024
  • Recently, electric skateboards have been used as a means of personal transportation due to their convenience and simplicity of operation, but the conventional skateboards driven by timing belts or hub motors have disadvantages such as low driving torque, high current and vibration. Therefore, in this paper, we propose a new type of electric skateboard that can run at high speeds for long periods of time so that it can be used as a auxiliary means of transportation. The planetary gear and motor unit are combined and installed inside one drive wheel, and power is supplied to the wheel through the integrated driving unit to prevent high currents and enable high-speed driving. First, the allowable current and running speed of the electric skateboard were set for efficient personal transportation and the appropriate reduction ratio, modules, and planetary gear dimensions were determined by comparing the torque required for the wheel axis and the maximum output torque of the motor. Additionally, an appropriate suspension device was added to reduce driving vibration for user convenience, and the feasibility of the proposed in-wheel gearbox was experimentally verified through fabrication.

Analysis of the Utilization Characteristics of Electrical Power and Equipments on the Farms (농촌의 전력및 전기기기의 이용특성분석)

  • 박승우;류한열
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.17 no.4
    • /
    • pp.3943-3955
    • /
    • 1975
  • The purposes of this study are to evaluate the utilization characteristics of electrical power consumption, to grasp the present trends in the use of electrical equipments, to estimate the demand factor and load factor being held, and to evaluate the efficiency of electical uses for the recently electrified farms cultivating paddy rice. For the purposes, 109 sample farms located in eleven villiages electrified in six different years from 1968 to 1973, were chosen at random and investigated on 35 items concerning to electrical uses and wiring systems. The survey was carried out in 1975, in the vinicity of Suweon city. The results are summarized as follows: i) The average annual power consumption on sample farms is considered to be low, being 242.9 Kwh. in 1974, and varied according to the different electrified year and size of cultivated land, respectively. It has significant positive correlation to the area of farm, too. ii) Between the number of year of electrical uses and the power consumption, there is very significant positive correlation, which could be expressed as Y=43.041+16.108 X, where X represents the number of years of electrical uses. The annual increment of power consumption is much greater at the beginning of the electrification than that at the later years, its average being approximately 20 percent. However, it is recommended that any estimation of long-term increments should be carefully investigated. iii) The monthly power consumption varies considerably throughout a year, in which the heaviest farm load occurs in November. Observing the seasonal variation of consumption, the winter-time is the heaviest season while the summer is the lowest. The result implies house lighting is chief contribution to the present electrical consumption on the farms. Comparing the variation of monthly consumption ratios between the sample farms and industries, the electrical uses on the farms are independant of the industrial uses, and further, the agricultural uses are of inverse pattern to the farms from the results that there is negative correlationship between them, iv) The number of electrical equipments used on the farms are occupied chiefly by lighting sources. Next to the lighting sources, household appliances of small quantity and some motors are used. The mean electrical quantity is about 1, 127.4 watt, which corresponds to about 37.6 per cent to the contracted quantity. The composition of quantity is chiefly occupied by the electrical motor of about 1.5 hp., single-phased. The number of the annual utilization hours of each equipment is tabulated in Table IV-5. In contradiction to the high utilization of lighting sources and small household appliances, the motor is poorly used for approximately 22 hours in a year. v) More than 55 per cent of farms want to purchase new electrical equipments such as small household appliances and electrical motors in their number. The impulse of purchasing such items is stimulated by the contacts to the mass media and their knowledge on such equipments. Consequently, the increase of electrical uses could be prompted by such trials as education and demonstration. vi) The demand and load factors on the farms vary considerably according to the greater variation of the power consumption, daily or monthly. The daily demand factor is 22.4 per cent and load factor 18.6 per cent, while the annual demand factor is 1.3 per cent and load factor 70 per cent approximately. Therefore, the low efficiency of construction cost requires re-evaluation of the present contracted quantity of 3 Kw. or increase of electrical uses. vii) The electrical energy on the farms devoted chiefly to lighten the farm residences does not contribute to the farm incomes. Consequently, the cost of electrical consumption presses considerably upon the farm economy. Therefore, there is great need to build up the electrical uses on the farms through the development of new works and techinques to utilize any electrical equipments on the production of farm products. Further more, such the development should be related to increase the actual income of the farm consumers.

  • PDF