• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.4
• /
• pp.97-103
• /
• 2009

Since a demand for an extensive range of earthmoving equipment like a hydraulic excavator with a capacity of 85tons has been asked in construction fields, a performance of its track drive unit has to be verified experimentally. Among the verification of the performances, a torque measurement is at issue, in which a torque meter is utilized widely. However, the very large scaled torque meter is necessary when a discharged torque from the track drive unit is increased significantly. In addition, the price for experimental set-up of a torque meter is too high due to its limitation of the geometry such as long length, and a break down in operation occurs frequently. In this study, to measure a high torque up to 200,000Nm, a new technique was proposed as an alternative of conventional measurement by using a torque meter. The new technique enables to measure the high torque stably in a compact space via a torque arm and two load cells. The experimental results showed a propriety of the proposed torque measuring technique for a track drive unit with very large capacity.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.10 no.3
• /
• pp.181-188
• /
• 2007

This paper presents a torque control method of a hydraulic actuation system for measuring the dynamic stiffness of missile fin actuators. We propose a new control technique called Dual Dynamic Torque Feedback Control(DDTFC), which improves the stability of the torque control system and enables fast tracking of torque command. The developed control scheme is derived from the physical understanding based on mathematical modelling and analysis. The dynamics of hydraulic torque control servo-system is unravelled via physics-based modelling and nonparametric system identification. In order to verify the effectiveness of the method, the experiment is carried out with a test equipment for measuring the dynamic stiffness. The experiment and simulation results show that DDTFC gives stability improvement.

• Proceedings of the KIEE Conference
• /
• 1998.07a
• /
• pp.290-292
• /
• 1998

The driving torque acting on a rotatable disk of watthour meter is proportional to the effective power. The aim of this paper is to show how the driving torque on a disk can be measured by a LVDT transducer. This driving torque is obtained by the theoretical computation. To verify the computated result, the LVDT as torque transducer, was used. A comparison is made between computed and measured torques.

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.387-390
• /
• 1995

We have developed a new method for measuring the M-H hysteresis loop of a spheroid-shape magnetic material having a uniaxial anisotropy and discussed its accuracy at fields near the coercivity. Our torque magnetometric method simultaneously gives the saturation magnetization and the remnant magnetization. Furthermore, the coercivity depending on the applied field orientation is accurately measured by this simple technique. An accuracy of the present method is negligibly affected even at fields near the coercivity, where the magnetization is not uniform. The technique makes a torque magnetometer an extremely high sensitive tool for measuring M-H hysteresis loop.

• The Korean Journal of Rheology
• /
• v.11 no.1
• /
• pp.57-65
• /
• 1999

In order to measure yield stress of PIM feedstocks simply and effectively, a yield stress measuring technique was developed by a vane method. The vane method had an advantage that there was no wall-slip, while it had a drawback that it could not measure viscosity change at various shear rates. A Newtonian fluid was tested for the appropriateness of the measuring technique. The end effect of a vane was checked to produce an acceptable error. The torque peak has been considered to be developed at yielding of non-Newtonian fluids with yield stress. However, it was influenced very much by control system of the instrument so that the torque value at the stable region was taken to calculate yield stress. Torque at zero rotational speed was obtained by extrapolating the torque values at various speeds to remove the effect of the rotational drag. As general verification, yield stress of feedstocks made of Tungsten carbide powder with wax-based binder was measured at different temperatures and various powder concentrations.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.866-872
• /
• 2014

The purpose of this paper was to find an effective method for measuring electromagnetic torque produced by a brushless DC motor with single-phase current sensing in real-time. A torque equation is derived from the theory of brushless DC motor. This equation is then validated experimentally with a motor dynamometer. A computer algorithm is also proposed to implement the electromagnetic torque estimation equation in real-time. Electromagnetic torque is a linear function of phase current. Estimating the electromagnetic torque in real-time using single-phase current is not appropriate with existing equations, however, because of the rectangular alternating-pulse nature of the excitation current. With some mathematical manipulation to the existing equations, the equation derived in this paper overcame this limitation. The equation developed is simple and so it is computationally efficient, and it takes only motor torque constant and single-phase current to evaluate the electromagnetic torque; no other parameters such as winding resistances, inductances are needed. The equation derived is limited to the three-phase brushless DC motor. It can, however, easily be extended to the multiphase brushless DC motor with the technique described in this paper.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.6
• /
• pp.34-42
• /
• 2000

In this paper conventional technique will be described, which can be used for the measuring various parameters of induction motor. This is followed by presenting some other, alternative, techniques. The two tests are described which are suitable to obtain the electrical parameters of symmetrical 1hp three-phase squirrel-cage induction motor. These are the blocked rotor test and no load test. By the application of these, it is possible to determine the parameters which are presented in the steady-state equivalent-circuit of determining an induction motor. One conventional method of determining the inertia of an induction motors is obtained by performing retardation tests. The angular rotor speed of the motor is monitored, following its disconnection from the stator supply. Since the inertia torque J dw/dt contains the inertia coefficient J and the friction and windage torque Bw contains the coefficient B, then J and B can be determined by performing retardation tests.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.1
• /
• pp.19-24
• /
• 1999

In this paper the emission characteristic of the ship's diesel engine with CPP(Controllable Pitch Propeller) were investigated under the passage test on the sea. As the results it is confirmed that the NOx.$CO_x$ concentrations increase as the engine speed increases and the torque decreases. but the amount of NOx, COx emissions(g./k Wh) decrease as the torque increase regardless of the engine speed. Also it is compared with the NOx concentra-tions measured by the two method-ECC(Electrochemical Cell)and CLD(Chemiluminescence Detector)for the correct measurement and the ECC indicated higher value than the CLD.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.750-752
• /
• 2003

This paper presents a method of tolerance analysis for a electric machine. Tolerance analysis technique is required to find the tolerance band of design variables and estimate the characteristic distribution of the electric machine, because that manufacturing tolerances as well as measuring errors have a great influence on the electric machine. Therefore, this paper introduces Stochastic Response Surface Methodology to achieve the tolerance analysis. As an example, the tolerance analysis is applied to the analysis of torque characteristics for a BLDC motor from the electric point of view.

• Journal of Magnetics
• /
• v.20 no.1
• /
• pp.8-10
• /
• 2015

The magnetic anisotropy field plays an important role in spin-orbit-torque-induced magnetization dynamics with electric current injection. Here, we propose a magnetometric technique to measure the magnetic anisotropy field in nanostructured ferromagnetic thin films. This technique utilizes a magneto-optical Kerr effect microscope equipped with two-axis electromagnets. By measuring the out-of-plane hysteresis loops and then analyzing their saturated magnetization with respect to the in-plane magnetic field, the magnetic anisotropy field is uniquely quantified within the context of the Stoner-Wohlfarth theory. The present technique can be applied to small nanostructures, enabling in-situ determination of the magnetic anisotropy field of nanodevices.