• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.2
• /
• pp.120-127
• /
• 2008

The constant velocity joint(CVJ) used for transmitting torque to the front wheels is an important part in automotive drive system. There are several types of constant velocity joints. Typically, they are classified by fixed and plunging constant velocity joints. The axial force generated in plunging constant velocity joints influences significantly the noise, vibration and harshness. For heaps of time, many constant velocity joint markers have been studying and developing a valid method to reduce the axial force and extensive tests have been carried out on rigs. This paper presents the analysis method to predict the axial force of a double offset constant velocity joint(DOJ), a kind of plunging constant velocity joint, and the influence of ball-cage dimension tolerance on the axial force.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.13 no.6
• /
• pp.12-15
• /
• 1976

This paper presents the realization method of 90$^{\circ}$ constant phase shifter in the VHF band, constructed by the entirely differens idea from the conventional method of the realization of constant phase shifter in the audio frequency range. The construction of 90$^{\circ}$ constant phase shifter is. simple and can be easily realized by using the distributed constant element, transmission line, and the lumped constant elements, R,C,L.

• Communications of the Korean Mathematical Society
• /
• v.13 no.3
• /
• pp.683-689
• /
• 1998

There have been developed many integral representations for Euler's constant some of which are recorded here. We are aiming at showing a (presumably) new integral form of Euler's constant and disproving another integral representation for this constant which were recently proposed by Jean Angelsio, Garches, France, in American Mathematical Monthly. By modifying the Angelsio's incorrectly proposed integral form of Euler's constant, we also provide an integral representation for Euler's constant.

• Proceedings of the KSR Conference
• /
• 2000.05a
• /
• pp.116-122
• /
• 2000

This paper presents a simulation method with constant power model for the train load. In power system simulation loads could be modeled as a constant power, constant current, constant Impedance or a function of voltage and frequency. At this time, however, representing a train load as the function is difficult because of the lack of data. Therefore as a first step, simulation method with a constant power model fer a train is studied, and the test result is compared with the simulation result using the constant Impedance model.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.3
• /
• pp.365-373
• /
• 1996

This paper presents the effects of rotor time constant variation and the on-line tuning algorithm of the rotor time constant. If the value of the rotor time constant is set incorrectly, the IFOC (Indirect Field Oriented Control)scheme exhibits deteriorated performance according to the wrong slip command. These variation effects of the rotor time constant are caused by the slip calculator where it is known that the rotor time constant play an important role in the aligned rotor flux. Using the two torque angles (stationary torque angle, rotating torque angle), the variation of the rotor time constant is identified, and the rotor time constant of the controller is tuned to the proper value of the machine. As the result, with the proposed algorithm, the dynamics of the deteriorated IFOC system, where the rotor time constant is varied, is improved. For the purpose of the validity of this proposed algorithm, the computer simulations and the experiments have been performed and the explanation of the results is presented. (author). refs., figs., tab.

• Journal of Wind Energy
• /
• v.3 no.2
• /
• pp.34-41
• /
• 2012

The paper is focusing on investigating the control characteristics of the baseline controller of 5 MW wind turbine provided by NREL(National Renewable Energy Laboratory). The baseline controller consist of two control logics, a maximum power tracking control below the rated wind speed and a constant power control above the rated wind speed. In the low wind speed, the mean generator power for changing the turbulent intensity and the optimal constant is studied through numerical simulations using FAST program. On the other hand, the constant power control logic and the constant control logic are compared in the high wind speed. It is confirmed that optimal constant is closely related to the turbulent intensity in low wind speed region and the constant torque control has better performance than the constant power control with respect to mechanical load in high wind speed region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.1
• /
• pp.53-57
• /
• 2012

In this paper, by designing 20 W class driving circuit for driving high-power LED (Light Emitting Diode), we are going to comparatively carry out the analysis of characteristics for power circuit according to each design method. In this case, 200 V 60 Hz was performed as input data. The electrical characteristics such as voltage, current and ripple are checked for constant current circuit and constant voltage circuit in the LED module. In addition, as the ripple has an influence on illumination of LED light, low temperature working (-20 [$^{\circ}C$]) and high temperature working(80 [$^{\circ}C$]) are measured to make sure the ripple characteristics in accordance with temperature. In low temperature operation -20 [$^{\circ}C$] measurements, both constant current circuit and constant-voltage circuit were less impacted on input fluctuation, whereas in the high temperature operation 80 [$^{\circ}C$], current voltage in constant voltage circuit was surge after 430 [hour]. Voltage current ripple of constant current circuit was much less than constant voltage circuit, therefore we can show that constant current circuit is more stable.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.03a
• /
• pp.471-477
• /
• 1999

A new stress, load and displacement controlled direct shear apparatus has recently been developed at the Hyundai Institute of Construction Technology This direct shear apparatus is capable of testing of rock joint under constant normal stiffness, constant normal stress or constant normal load boundary conditions. This paper describes this direct shear apparatus and illustrates results of shear tests at constant normal stress condition, constant normal load condition and constant normal stiffness condition with dental stones which have a same joint roughness and unconfined compressive strength.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.4
• /
• pp.688-693
• /
• 2009

The response characteristics of power system frequency are determined by generator droop characteristics and load damping properties. The characteristics of governor droops are termed by generators constant, while those of load damping by load constant. In this paper, the generator constant and the load constant are assessed by measured data at the event of generator trips.

• Bulletin of the Korean Mathematical Society
• /
• v.56 no.6
• /
• pp.1569-1575
• /
• 2019

In this paper we calculate three geometric constants, namely the von Neumann-Jordan constant, the James constant, and the Dunkl-Williams constant, for Morrey spaces and discrete Morrey spaces. These constants measure uniformly nonsquareness of the associated spaces. We obtain that the three constants are the same as those for $L^1$ and $L^{\infty}$ spaces.