• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.104-109
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• 2016

The noncontact vibration exciter system using the electro-magnet for a thin plate is studied in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion of thin plate is derived. The main purpose of this experiment is to match the input-frequency and response frequency of thin plate. The test equipment is configured to vibrate on both sides of the thin plate using the electro-magnet. Two frequencies(input frequency and response frequency) in our experiments show very good agreement. This study results will contribute to basic investigate of an alternative air-knife system for the steel industry.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.11a
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• pp.117-138
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• 1999

.8-VSB Modulator for Digital Television . ERRI'S ATSC VSB EXCITER . Pre-Corrector . Field Test . Lab Test

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.101-107
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• 2016

The main target in this paper is the localization of VME Type EPSM in Generator Exciter(EX2100) System. Developed EPSM has the compatibility with the existing product in the structure and shape and electrical feature and so on, but it has a much improved capacity and reliability in comparison with origin company product. this paper, to improve these functions, put emphasis on protection, monitoring, power capacity increase(over 120%), an enlarged scale of input voltage supply, AC/DC dual voltage use and so on. After manufacturing product localization, it was carried out several tests for the performance and reliability verification of developed product. These tests were performed in Authorized Inspection Agency(KTL) and field application test and maker self-test were additionally performed. Finally, the results of all tests were "success".

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.218-225
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• 2013

Vertically-launched missiles are supported as erected vertically in the vertical launching system of warship, and they should be mounted in the same way when vibration-tested. However, mounting missiles vertically makes a fixture, which is a supporting structure, bulky and heavy so requiring a high-performance exciter. Mounting missiles as laid down horizontally in a vibration test is economical regarding fixture manufacturing and exciter performance, but it makes test results incorrect because the different mounting direction has effects on the test results. A bending moment due to missiles' weight happens to missiles, and resilient mounts, which support missiles in the vertical launch system, deflect differently from the real situation because of the static deflection of these mounts due to missiles' weight. If the resilient mounts supporting missiles have nonlinear force-deflection characteristics, vibration test results become more different from the true results. This paper proposes to support missiles with an additional resilient mount such as a bunge code in order to solve those problems coming from mounting vertically-launched missiles as laid down horizontally in vibration tests. The proposed approach enables to obtain the same test results as in their actual mounting condition even though vertically-launched missiles are mounted in a different direction.

• Journal of Biosystems Engineering
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• v.27 no.5
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• pp.391-398
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• 2002

During handling unitized products, they are subjected to a variety of environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization of pallets has been resulted in a reduction of the shock hazards. This has caused an increasing interest in research focused on vibration caused dam age. Damage to the product by the vibration most often occurs when a product or a product component has a natural frequency that falls within the range of the forcing frequencies of the particular mode of transportation being used. Transportation vibration is also a major cause of fruit and vegetable quality loss due to mechanical damage. This study was conducted to determine the vibration characteristics of the corrugated fiberboard bones for packages of pears, and to investigate the degree of vibration injury of the pears in the boxes during the simulated transportation environment. The vibration tests were performed on an electrohydraulic vibration exciter. The input acceleration to exciter was fixed at 0.25 G for a single container resonance test and 0.5 G for the vertical stacked container over the frequency range from 3 to 100 Hz. Function generator (HP-33120A) was connected by wire to the vibration exciter for controlling the input acceleration at a continuous logarithmic sweep rate of 1.0 octave per min. The peak frequency and acceleration on the single box test were 22.02 Hz, 1.5425 G respectively, and these values on the vertical stacked boxes were observed from the bottom box 19.02, 18.14, 16.62 and 15.40 Hz and 2.2987, 3.7654. 5.6087, and 7.9582 G, respectively. The pear in the bottom box had a slightly higher damage level than the fruit packed in the other stacked boxes. It is desirable that the package and transportation system has to be so designed that 15∼20 Hz frequency will not occur during the transportation environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1275-1280
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• 2015

A large-sized exciter that vibrates a two-ton component is required to simulate the field operating conditions of a counterweight of an excavator. However, it is difficult for a small-medium sized company to obtain a large exciter for the life test of a counterweight which is an equivalent counterbalancing weight that balances a load. Therefore, in this study, we developed life test equipment for evaluating the reliability of construction machinery weighing about two tons. It simulates the field operating conditions using rotational vibrators consisting of electric motors. A failure analysis of the counterweight was also performed for the major components. Field data acquired from various sites were applied to the life test design of the counterweight. Finally, a zero-failure qualification test based on the accelerated life test was designed, and there was no failure during the test, which guarantees a life of $B_5$ 10,000 hours.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.145-150
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• 2020

Water wall tube is one of the major factors consisting of a fluidized bed boiler and it plays very important role for the generation of electricity within the boiler. But these water wall tubes within the fluidized bed boiler are subject to the ware and corrosion caused by the high temperature gas and the flowing medium. If water leak is occurred, the secondary damage by the water leak will occur. As a result of that, the power generation efficiency decreases noticeably. Therefore, the maintenance of the water wall tube is very important. In this study, we designed a exciter sensor based on simulation and composed a remote field eddy current system for the defect evaluation of the outer water wall tube. Starting from the shape design of exciter, we conducted simulations for various design factors such as the water wall tube size, material, frequency, lift-off and so on. Based on the results, we designed the optimum exciter sensor for the water wall tube test within the fluidized bed boiler.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.296-301
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• 1998

In this experiments of design, vibration evaluation, and test of vehicles, aircraft, and other mechanisms the development of vibration simulator that serves environment similar to real fields takes lots of advantages. Especially, in the real field test of vehicles it possesses the advantages of showing the dynamic characteristics of the vehicle. In this study, to investigate the validity and fitness of proposed 6DOF parallel link mechanism we simulated that mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.57-60
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• 2005

Modal parameters of a structure are the important factor to control the missile maneuver. In general, a dummy structure is used for the modal test of missile structure instead of the real warhead and propellant because there may be the danger of a explosion by the electric shock of test equipment, such as the exciter and the power amplifier. However, the modal testing of a real missile structure is required to acquire the modal parameters and to analyze the missile performance accurately. The new test system and technique are developed to get rid of the danger and secure the safety during the testing. This test system is made of with the computer network system and controlled remote from test site. Using His new test system, the modal test of real missile structure is performed successfully and its validity is proven.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.915-916
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• 2007

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, Exciter, CLR, Back Up Breaker, Making Switch and TRV etc. Especially Back up Breaker and Making Switch are very important equipments to test the short circuit test. A role of a Back up Breaker is to break high-voltage and high-current for short circuit test and a Making Switch should be operated always same speed/time and kept electrical-mechanical characteristics to make the voltage and current of short circuit test. This study introduces to the short circuit test also to kinds, principal movements and compare them of Back up Breaker and Making Switch.