• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.288-291
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• 2001

In steel plant, load torque of mill driver motor is changed periodically because working state and idle state are repeated and load current of working state is necessarily higher than rated motor current. The over current limiter is one of the basic thermal protection method from over heating. In this paper, we analyzed the structure of over current limiter for motor and motor driver systems, developed over current limiter with same operation and structured warning system of action of over current limiter. As using this warning system, we can avoid abrupt plant stop by over current limiter in mill driver and lessen producing loss by plant stop. The developed warning system of action of over current limiter is exactly inspected by computer simulation md analysis of acquired data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.1
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• pp.61-65
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• 2012

Some works about the current sensorless control of a synchronous reluctance motor have been presented. However, there is no analysis about the performance and the detuning effect of the current sensorless control. This paper presents the problems and the detuning effect of the current sensorless control of a synchronous reluctance motor by simulation results. In addition, torque limiter is proposed to limit the torque current within the torque limit.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.262-268
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• 2014

This research introduces the structural design and the validation results of the flexible high speed coupling for 2MW class wind turbine which transmit and cut off torque between gear box and generator. The high speed coupling requires electrical insulation to prevent electrical surface damages on gear box. Therefore glass fiber reinforced plastics is applied to absorb the vibration and deformation of power train and to transmit required torque. Finite element analysis was performed to optimize the thickness and accumulation number of glass fiber reinforced plastics. Torque limiter which cut off the abnormal torque is designed in frictional disc type. The design of the coupling was validated with the performance test of prototype.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.361-366
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• 2019

Exchanging sheets for patients is one of the worst and one of the factors that makes the nursing environment difficult. Many beds with various functions for the patient have already been developed, but there is no device for automatically changing the sheets. In this study, we developed and tested the first automatic sheet changer for a medical bed and verified its performance. The developed automatic seat changer uses a torque limiter to properly adjust tension and exchange a dirty sheet and a new seat at the same time. The designed automatic sheet changer was experimentally confirmed to be properly operated and installed in a integrated multi-functional bed with bed sores prevention and automatic patient transfer functions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.150-157
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• 1999

In this study, the loader was completed that has 4-wheel gear driven drivetrain of study (Ⅰ), the 4-wheel steering with power wheel type, all-wheel traction system, and joy-stick type lever for hydraulic control valve. From driving test of the developed 4WD and 4WS type loader, we obtained that the minimum circling radius and the necessary width in circling motion reduced about 40% and 33% compared with 2WS type loader. Also, all-wheel traction system could keep the tires glued to the ground with greater stability, the power steering allowed a smoother operation, and the joy-stick type lever offered easily to control. Thus, the developed loader having these functions was very fit in a small cattle shed or rugged ground.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.9
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• pp.396-402
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• 1986

Although the structure of the brushless DC motor is similar to the one of the permanent magnet synchronous motor, its operating characteristics are the same as those of the permanent magnet DC motor. This is the reason that the commutators and brushes in the permanent magnet DC motor can be replaced by the power semiconductor devices and rotor position sensors for the brushless DC motor. In this paper, a current control method is presented to make a sinusoidal current waveform for constant torque generation and the operating characteristics of the brushless DC motor using the resolver as the rotor position sensor is also presented and experimented.

• Journal of Wind Energy
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• v.10 no.4
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• pp.20-27
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• 2019

High-speed shaft coupling in a wind power system transmits power and absorbs variations in length and spindle dislocation between the gearbox and generator. Furthermore, the coupling has an insulation function that prevents electrical corrosion caused by the flow of the generator's current into the gearbox and prevents overload resulting from sudden power failure from being transferred to the gearbox. Its design, functions, and part verification are described in the IEC61400 and GL Guidelines, which specify that the part must have a durability life of 20 years or longer under distance variation and axial misalignment between the gearbox and the generator. This study presents the design of a high-speed coupling through composite stiffness calculation, structural analysis, and comparative analysis of test and theory to identify the characteristics of high-speed coupling for a large-capacity 6 MW wind power generator. A prototype was fabricated by optimizing the manufacturing process for each part based on the design, and the reliability of the fabricated prototype was verified by evaluating the performance of the target quantitative evaluation items.