• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.1
• /
• pp.77-82
• /
• 2008

Strain-gauges have been dominantly used to measure strain at various points on a rotor, however, either a slip ring or telemetry has to be used to send sensor signals to data acquisition instruments at stationary side. Both slip ring and telemetry have numerous inherent problems which force severe limitations in real applications. This paper introduces a new rotor condition monitoring system using FBG(Fiber Bragg Grating) sensors and a rotary optical coupler. A single optical fiber with many FBG sensors is installed on the rotor and an optical dynamic interrogator is installed at stationary side. The sensor signal connection between rotating part and stationary part is made by the rotary optical coupling method which makes use of light's unique characteristic-light travels through space. Broad band light source from the interrogator travels to the optical fiber on the rotor and reflected FBG sensor signals travel back to the optical fiber on stationary side and are connected to the interrogator. Rotary optical coupler's insertion loss change due to rotation is compensated by using a reference sensor installed at the center of the rotor. The proposed system's performance has been successfully demonstrated by accurately measuring strains at 5 points on a blade rotating at high speed.

• Journal of Power System Engineering
• /
• v.9 no.4
• /
• pp.51-57
• /
• 2005

In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. The rotary dryer is the way that is to make substance transmission and heating using hot air between sludge particles and heated gas. In this paper, we performed a numerical analysis of the inner air flow of the 3-pass rotary dryer through the changing rotational speed from 3rpm to 10rpm. In this result, we found that 3rpm is effective to dry material in terms of heat transfer because large scale velocity fluctuation is occurred inside the first and second drum. Also we confirmed that 5rpm and 8rpm showed up uniform flow at the center area of the first drum.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1083-1086
• /
• 2003

Recently, the study on bearingless motors which integrate both motor and magnetic bearing function in one stator is very active, as many machines have high rotational speed, high precision, smaller size and lighter weight. In this paper, we propose a novel rotary actuator including function of axial bearing using Lorentz force as a preceding research for development of a bearingless motor. As using Lorentz force, this type has some merits such as the linearity of control force, freedom from flux saturation and high efficiency unlike conventional rotary actuators using a reluctance force. This type is cotrolled independently in levitation and rotational directions respectively. It shows by mathematical expression of levitation force and torque in the proposed rotary actuator. And also, the levitation force is generated by magnetic interaction between the magnetic materials and the rotational torque is generated by Lorentz force. Finally. for verification of this proposed system, a prototype is made and some experiments will be performed in the near future.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.5
• /
• pp.118-123
• /
• 2004

The compressor has one of important roles in refrigeration cycle and it determines refrigeration efficiency and quality This paper aims to monitor rotary compressors for room air conditioners by using Acoustic Emission(AE) technique. The reliability of rotary compressors has been evaluated through visual inspection on them after long term test. This paper describes methods for acquisition and processing AE raw signal to monitor the state of rotary compressor. A detecting method of abnormal compressor in real time is suggested and special-purpose monitoring system which can be applied to automatic manufacturing line is developed using one-chip microprocessor at low cost.

• Journal of the Korean Society of Combustion
• /
• v.18 no.3
• /
• pp.9-23
• /
• 2013

A rotary kiln furnace is one of the most widely used gas-solid reactors in the industrial field. Although the rotary kiln is a versatile system and has different size, approach to the reactor modeling can be generalized in terms of flow motion of the solid and gas phases, heat transfer, and chemical reactions on purpose. In this paper, starting from a zero-dimensional model and extending to higher dimension and comprehensive models, overall procedure of the design development of rotary kiln reactors and considerations are presented. The approaches to performance analysis of the reactors are introduced and examples of application cases are presented.

• Journal of Biosystems Engineering
• /
• v.36 no.3
• /
• pp.163-170
• /
• 2011

Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.1
• /
• pp.41-48
• /
• 2019

This paper deals with the design of the L-band rotary joint, which is a core part of the tracking radar system. The rotary joint is a part that is mounted on the rotating parts of the tracking system antenna, which smoothly transmits RF signals with minimizing signal insertion loss. To improve the insertion loss of rotary joint, 1) dielectric materials, 2) design of distribution ring and 3)dielectric shape are studied. The performance of proposed rotary joint is compared with the conventional product. The prototype rotary joint showed a max insertion loss of 0.68dB, that is improved about 46% compare with conventional product which insertion loss was 1.26dB.

• Journal of Korean Society for Quality Management
• /
• v.47 no.3
• /
• pp.437-451
• /
• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.819-826
• /
• 2000

This study was performed to develop a measurement system of tractor field performance for plow and rotary operations. Measurement system for tractor consisted of torque sensors to measure torque of drive axles and PTO axle, speed sensors to measure rotational speed of drive axles and engine, microcomputer to control data logger, and data logger as I/O interface system. The measurement system was installed on four-wheel-drive tractor. Four-element full-bridge type strain gages were used for torque measurement of drive axles and optical encoders were used to measure speeds of drive axles and engine. Slip rings were mounted on the rotational axles. Signals from sensors were inputted to data logger that was controlled by microcomputer with parallel communication. Sensors were calibrated before the field tests. Regression equations were found on completion of the calibrations. The field experiment was performed at paddy fields and uplands. Rotary and plow were used when the tractor was operated in the field. Travelling speeds of the tractor were 1.9 km/h, 2.7 km/h, 3.7 km/h, 5.5 km/h, 8.2 km/h, and 11.8 km/h. Operating depths of implements were maintained approximately 20cm during the tests. Torque data of drive axles were different at each location during plow and rotary operations. Results showed that torque of rear axles were greater than those of front axles. Total torque were 6860 - 11064 Nm at the upland and 7360 - 14190 Nm at the paddy field for plow operations. It was found that torque at the paddy field were about 20% greater than those at the upland for plow operations. Torque data showed that rotary operations required less power than plow operation at the paddy field and the upland. Torque measurements at each axle for rotary operations were only 8 - 16% of plow operations in the upland and 15 - 20% in the paddy field.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.693-697
• /
• 1990

A position control system is developed for an electro-hydraulic servo actuator with coaxial rotary spool, where the actuator is controlled by stepping motor. The position control system is utilized to develop the wireless remotely controlled crane system. And remote engine control system is also developed. Finally, to show the validity of this system, some experimental results and field test results am presented.