• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1784-1786
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• 1996

It is necessary to eliminate the broad band noise which frequency is in a few kHz to MHz in the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices like a filter and surge suppressor are developed to cut off the noise. But those device could not disconnected from the power line, so it remain some problem and on be used in limited area, In this paper, we present performance test results NCT(noise Cut Transformer) with excellent performance for reducing the high frequency noise and surge existing in the power line.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.957-959
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• 2005

A noise reduction equipment in power systems was device combined in a passive element such as the form of L, R and C. A analysis of frequency characteristics for the transformer models shall be considered the additional capacitance between the windings($C_{ps}$), terminals($C_s$), and winding-ground($C_g$). A noise in transformer is modeled by take account into the different frequency. In case of the high frequency, transformer windings with stray capacitance have lower impedance. Therefore a noise is transferred from primary winding to secondary winding. Noise Cut Transformer(NCT) was the noise reduction device and was normally single phase two-winding type transformer. We analyzed frequency characteristics using the nodal network analysis with the equivalent circuit and the simulation of the MATLAB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.850-859
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• 1998

Broadband noise with frequency components in the range from several kHz up to tens of MHz is widespread in the AC power line. Noise filter or surge suppressor, often used to suppress the conducted noise, have a poor performance in reducing the common-mode. In this paper, we proposed a lumped-circuit analysis model for Noise Cut Transformer(NCT) which can be used to suppress both the common mode and normal-mode noise. The simulations with our model show a good agreement with experimental results. It has been also shown that our NCT is superior to noise filter and general isolation transformer in reducing the conducted noise.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.146-154
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• 1998

Broadband noise with frequency components in the range from several kHz up the tens of MHz is a major obstacle factor in normal operation of the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices such as filter and surge suppressor are used to cut off the noise. But those devices could not disconnected from the power line, so they result in poor common-mode of NCT as well as insulation characteristics as a isolation transformer in addition faraday shielding and proposed analysis model of NCT having tow functions of surge and noise reduction. The simulated and experimental results for the surge suppression characteristics are compared and evaluated for designed protype 1[kVA] NCT.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.420-423
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• 1995

The electric arc welding machine with high-frequency inverter is studied in this paper which could make more saving in energy than conventional ones with inherent low efficiency. The inverter circuit has been already adopted to special welding machines such as MIG and TIG for improving operating performances so much. But this adoption has not be applied to conventional ac arc welding machine until now. The proposed technology for higher efficiency is to apply the high frequency inverter, together with noise-cut transformer. Overall output characteristics are investigated in aspect of cost and circuit performance. The proposed system is conducted practical experiments using PWM controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.7
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• pp.783-789
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• 2008

This experimental study describes the noise reduction and the feasibility of short current of a silencer for a high voltage COS(cut out switch) fuse of a transformer. When a high voltage COS fuse becomes a short circuit by the over current, the strong impulse noise over 150 dB(A) is generated. For the purpose of the reduction of impulse noise, in this study, the diffuser type and the reactive type silencers have been designed and tested, respectively. And also the electrical test on the short current is performed. From the experimental results, the well designed reactive type silencer has been shown to have the noise reduction of about 20 dB(A). It has been found that the feasibility of short current for the COS fuse is closely related to the porosity of the silencer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.75-81
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• 2005

Recently an increase of sensor and power trandusers in control equipment system has caused many kinds of noise the mis-operation equipment and demage program memories of control circuits. In this paper, the noise character of the various control equipment system has been measured and analyzed. Additionally, the countermeasure to reduce noise like as Noise Cut Transformer, Equipotential Bonding, Power Noise Rejector, Noise Filter has been applied and confirmed the effective results to solve the trouble of noise.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.325-330
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• 2005

Recently an increase of sensor and power trandusers in control equipment system has caused many kinds of noise. These kinds of noise came out the mis-operation equipment and demage program memories of control circuits. In this paper, the noise generation of control equipment system han been measured and analyzed. Additionally, the effective protection equipments to reduce noise like as Noise Cut Transformer, Equipotential Bonding, Power Noise Rejector, Noise Filter has been applied and proposed the measured results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1415-1418
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• 2007

When a high voltage COS fuse becomes a short circuit by the over current, the impulse noise over 150 dB(A) with the strong pulse jet is radiated from the COS fuse of an electric transformer. For the purpose of the impulse noise reduction, in this study, a reactive type silencer with perforated panels are considered. The transmission loss of the silencer are calculated by transfer matrix method. The effect of the porosity, the distance between panels, and the number of perforated panel on the sound transmission loss is investigated and discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.22-29
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• 2002

The conventional neon transformer systems are very bulky and heavy because it consist of leakage type transformers made of silicon steel plates. In addition, it has problems in noise by a neon transformer and in possibilities of fire and electrical shock when neon tubes are destroyed. A protection circuit is designed for all types of neon transformer loaded with one or more neon tubes. Whenever the neon tube fails to be started up, comes to the life end, encounters faults with open-circuits at the output terminals of the neon transformer, the protection circuit will be initiated to avoid more critical hazards. The input of the transformer is automatically cut off when the abnormal condition occurs, preventing waste of no-load power. To improve such problems, in this paper, a new type of neon power supply systems for neon tube is designed and implemented using inverter type circuits and a newly designed lightweight transformer. In the developed neon transformer system, a 60［Hz］power input is converted to 20［KHz］high frequency using half-wave inverters, thereby the transformer reduces its size by 1/5 in volume and 1/10 in weight.