東洋電機技報 第105号

※ 技術論文、開発レポート、製品解説については東洋電機技報本文からの抜粋です。


Bearing Corrosion of Induction Motors

中村 雅憲、今柳田 明夫
Masanori Nakamura, Akio Imayanagita

In recent AC drive system many induction motors have been used as variable speed motors associated with PWM inverters. Semiconductor switching devices for inverters have changed from bipolar transistor to IGBT (Insulated Gate Bipolar Transistor),and switching frequency increased to about 10kHz. By this revolution in semiconductor technology the acoustic noise and mechanical vibration of motors were greatly decreased as well known.
However the failures of motor bearing driven by IGBT PWM inverter have been occurred. PWM inverters generate common mode voltage components in each phase that vary simultaneously against the ground potential. The high frequency current due to common mode voltage flows through stray capacitance between stator winding and stator iron core and then back to the inverter through earth cable of the motor frame. The impedance of earth cable is very important as key component of bearing currents. So, in our company a test motor was provided to measure bearing current directly and various evaluations about bearing corrosion have been examined.
This paper describes the mechanism of bearing current due to common mode voltage in case of separated basis with different earth cable impedance, and experimental results of bearing corrosion in various conditions at high frequency.

近年のACドライブにおいて、誘導電動機(以下、単にIMと略記する)をPWMインバータとともに可変速ドライブで使用することはごく一般的になってきた。半導体素子はトランジスタからIGBTへと変化し、キャリア周波数は10kHz前後と高くなり、スイッチングの立ち上がりも非常に急峻になってきている。 このような半導体素子の変革により、IMに流れる電流に含まれる高調波成分が大幅に低減されることとなり、騒音や振動などの低減につながったことは周知のことである。

Development of Real Time Load Simulator for Induction Motor driven by VVVF Inverter

田中 孝佳、大山 裕二、塩田 剛
Takayoshi Tanaka, Yuuji Ohyama, Takashi Shiota

Recently, requests on evaluation level of power electronic controller characteristics, such as energy saving, efficiency development, and pollution-free, are getting higher and higher. From the viewpoint of hardware technology, high voltage and fast switching devices and high performance data processing devices propose the measures to solve these problems. On the other hand, from the view point of software technology, source program for control system is getting more and more sophisticated and large-scaled. Much time and manpower are needed for manufacturers to confirm and evaluate behavior of such products under all the critical conditions. So, load emulation system based on estimation technique has been developed which can replace electric rotating machine by static components. The emulator system will assure high quality and reliability on both hardware and software in reduced time and/or manpower. This paper is the first report to show the principle and concept of Real Time Simulator (RTS) which emulates induction motor fed by VVVF inverter.



パナマ運河向け曳船用機関車 I(機関車システム)
Towing Locomotives for The PANAMA CANAL (I) (Locomotive System)

寺島 憲造、近藤 栄作、飯田 哲史、野村 英児
Kenzo Terashima, Eisaku Kondo, Norifumi Iida, Eiji Nomura

The Panama Canal was returned to the Republic of Panama from the United States of America at the end of 1999. In order to take the burden of the new era, it was decided to purchase towing locomotives after an interval of more than 40 years. After a keen competition in international tender, Japanese group consisting of Mitsubishi Corp. Ltd., Toyo Electric Mfg. Co., Ltd., Kawasaki Heavy Industries, Ltd., and Mitsubishi Heavy Industries, Ltd. was accepted for 24 of new proto-locomotives. The group has delivered first 8 locomotives this time. The Japanese group delivered the towing locomotives, which are now working in the Panama Canal thirty-eight years ago. On the basis of the track record, the Japanese group proposed a high-tech towing locomotive which has been developed focusing on resource saving and reduction of maintenance producing new technologies. Among manufacturers, Toyo Electric Mfg. Co., Ltd. was allotted to manufacture the electrical equipment and the windlass, Kawasaki Heavy Industries, Ltd. the body, and Mitsubishi Heavy Industries, Ltd. the gear unit
This report describes running system and electric devices of the towing locomotive. Former PCC (Panama Canal Commission) to which we deliver products is renewed and started as ACP (Autoridad del Canal de Panama) after the return.

この新時代を担うべく約40年ぶりに新機関車の導入が決定され、激しい国際入札の結果三菱商事(株)、東洋電機製造(株)、川崎重工業(株)、三菱重工業(株)の日本グループがプロト車両24両の受注に成功し、今回先行の8両を納入した。 日本グループは、現在稼動中の曳船用機関車を納入しており、今回受注したものはこの実績をベースに新しい技術を導入した省資源、メンテナンス低減を重視したハイテク機関車である。製造メーカは、東洋電機製造(株)が走行用電機品及びウィンドラス装置注1)、川崎重工業(株)が車体、三菱重工業(株)がギア装置を分担した。
なお、納入先であるPCC(Panama Canal Commission)は返還後ACP(Autoridad del Canal de Panama)として新しく発足した。

※ 第1号~第104号は目次のみの掲載です。