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Minami-rinkan, Japan

Kishino M.,Nagoya Institute of Technology | Mizuno Y.,Nagoya Institute of Technology | Nakamura H.,Toenec Corporation
Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP | Year: 2011

Insulation failure of motor windings is one of faults that are likely to occur during the lifetime of motors. The authors have proposed a novel and simple method to diagnose insulation failure in a stator winding in terms of "fault probability", which is calculated on the basis of feature distributions of magnitude and phase of current flowing into windings. Validity of the method was confirmed under no load condition in the previous report. In this paper, it will be shown that the proposed method is also quite effective under loaded conditions based on the results of a series of laboratory experiments using motors with an artificially introduced insulation failure in a stator winding. © 2011 IEEE.


Nakamura H.,Toenec Corporation | Mizuno Y.,Nagoya Institute of Technology
IEEJ Transactions on Industry Applications | Year: 2012

Short-circuit faults of winding due to the deterioration in the insulation is one of the most probable faults in motor drive systems. An easy and effective fault diagnosis method has been strongly required to assure operation with high reliability. This paper proposes a novel method for diagnosing both short-circuit faults and insulation deterioration in windings. This method involves an impulse voltage test and probabilistic process for gauging the probability of fault occurrence by considering the distributions of features depending on the condition of the winding. In this paper, first, we discuss the results of several impulse tests on the winding. Second, two features that represent the characteristics corresponding to the condition of the winding are induced, and their feature distributions are determined. Third, we introduce the probability that can be used to diagnose the condition of the winding. The average and standard deviation of both features are calculated. By using the calculated values and features observed in a target winding to be examined, the fault probability is computed. Finally, the usefulness of the proposed diagnosis method is verified by performing experiments involving the use of faulty and deteriorated windings. © 2012 The Institute of Electrical Engineers of Japan.


Iritani E.,Nagoya University | Katagiri N.,Nagoya University | Takaishi Y.,Toenec Corporation | Kanetake S.,Nagoya University
Journal of Chemical Engineering of Japan | Year: 2011

The single constant pressure filtration test for dilute colloidal dispersions has been newly developed for easily determining the pressure dependence of the permeability characteristics such as the average specific cake resistance. The method made use of the gradual variation of the effective pressure drop across the filter cake with time generated by using the filter medium with a high medium resistance. The correlations between the average specific cake resistance and the effective pressure were obtained from the flux decline data. The data of the flux decline behavior obtained for the various values of the slurry concentration, applied pressure and medium resistance were largely merged by the normalized form of the reciprocal filtration rate vs. the filtrate volume. The validity of the method was confirmed not only for slurries of bentonite, Hara-Gairome clay, and polymethyl methacrylate (PMMA), but also for nanoparticle colloids of bovine serum albumin (BSA) and silica sol. Copyright © 2011 The Society of Chemical Engineers, Japan.


Uejima H.,Nagoya Institute of Technology | Naruse T.,Nagoya Institute of Technology | Aoki M.,Nagoya Institute of Technology | Ukai H.,Nagoya Institute of Technology | Kobayashi H.,Toenec Corporation
IEEJ Transactions on Power and Energy | Year: 2012

Recent rapid introduction of photovoltaic power generations (PVs) causes several issues of power quality. First, reverse flow causes voltage rise of distribution lines. Second, since almost of residential PVs are connected to the distribution lines by single-phase, voltage imbalance is occurred by imbalance current of PVs. On the other hand, in Japan, almost high voltage consumers set up Static capacitors (SCs) to improve the power factor at their receiving points. However, the capacity of SC becomes excessive than required amount of capacity. Hence, the excessive amount of SCs may also cause voltage rise and harmonic voltage problems that is Ferranti Effect and harmonic resonance between SCs and inductance of lines. Under these backgrounds, the purpose of this study is to propose the new control method of SCs not only improving power factor but also solving power quality problems. The major point of the proposed method is to determine the capacity of three-phase type SCs and single-phase type SCs so as to minimize power loss of distribution line in a limitation condition of each power quality. © 2012 The Institute of Electrical Engineers of Japan.


Nakamura H.,Toenec Corporation | Yagami Y.,Nagoya Institute of Technology | Araki C.,Nagoya Institute of Technology | Mizuno Y.,Nagoya Institute of Technology
IEEJ Transactions on Electronics, Information and Systems | Year: 2015

In this paper, a new method is proposed to detect broken rotor bars in a cage induction motor. In this method, characteristic frequency components are extracted by a frequency analysis, and they are displayed on a two-dimensional feature distribution. Based on this feature distribution, a probability of broken rotor bar, which is used in the diagnostic indicators, is derived, and the condition of the rotor is diagnosed by the probability. The effectiveness of the proposed diagnosis method is verified by performing some experiments. © 2015 The Institute of Electrical Engineers of Japan.

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