M. Natsusaka

A low noise slotless parametric motor suited for use in quiet environment

The causes of acoustic noise generation and the capability of acoustic noise reduction of a slotless parametric motor have been investigated, and are compared with those of an ordinary motor. It was clarified that the acoustic noise of the parametric motor is lower than that of an ordinary motor, because the parametric motor has no slot and no tooth. When the motors are operated by a source with high-frequency components such as a square wave, the increment of the acoustic noise of the parametric motor is smaller than that of an ordinary motor. The parametric motor is suited for use in a quiet environment. The acoustic noise of the parametric motor is mainly generated by the clattering, and may be reduced by using 6.5%Si-Fe plates for the cores of the motor. The acoustic noise of the parametric motor can be reduced more by pressing a rotor shaft into the ball bearing, performing the varnish impregnation of windings, and enclosing the components of the motor by a frame. >

A planar transformer utilizing a parametric oscillation

This paper describes a new magnetic device consisting of a 12 mm/spl times/12 mm planar magnetic path-type transformer utilizing a parametric oscillation. The device is formed from a stack of 50% Ni-Fe laminations or Fe/sub 3/Co/sub 70/Si/sub 15/B/sub 10/ laminations, and is composed of magnetic paths with three legs and two parallel paths connecting the ends of those legs. Rectangular slots are made in the centers of the outside edges of the parallel paths, to cause a parametric oscillation in the device. The device operates as a parametric transformer and has an excellent voltage regulation with respect to load variation.

Performance of a miniaturized planar parametric transformer having an excellent voltage regulation

The fundamental performance characteristics of a 5 mm/spl times/7 mm sized planar parametric transformer fabricated by the wire-electric discharge machine are investigated. An excellent voltage regulation which is less than 0.9% at the rated value is obtained, when the supply frequency f is equal to 500 kHz. The capability of a multi-output-type parametric transformer is clarified.

A Laminated Core Type Parametric Induction Motor

A new type of a parametric motor using a laminated iron core is proposed in this paper. The structure and the fundamental performance characteristics of the motor are discussed. It is clarified that the output and efficiency of the trial motor are comparable to conventional single phase induction motors. The behavior of the magnetic flux in the stator core of the motor is also studied to understand the operating mechanism of the motor.

An analytical method of a planar parametric transformer based on the magnetic circuit model

A planar parametric transformer (5 mm/spl times/7 mm size) has various desirable features including excellent voltage regulation, overload protection, and noise rejection. In this paper, the no load performance of the parametric transformer is analyzed. A nonlinear second-order differential equation with time-varying coefficients is set up from the parametric oscillation circuit, and is solved by the harmonic balance method. The calculated values agreed approximately with the experimental ones.

Experimental Studies on Iron Loss in a Parametric Motor

Parametric motors offer numerous attractive features not found in ordinary motors, such as overload protection, simple construction, low cost, and low noise. This paper discusses the mechanism of iron losses occurring in the cores of a parametric motor, with a view to further improving the motors characteristics and putting it to practical use. It is shown that the greater part of the iron loss in the motor occurs in the common magnetic circuit, and is caused by an alternating magnetic flux in a direction perpendicular to the plane of the lamination. It is also shown that the eddy current loss occurring in the common magnetic circuit when the latter is radially excited is closely related to the magnetization process due to domain wall displacement.

Characteristics of a new orthogonal-core type induction motor having interesting features

The structure and the basic operations of a new orthogonal-core type motor, which can effectively utilize local energies such as wind and solar power are described. For this motor, the rotational direction, rotational speed and supplied powers are easily controlled by adjusting the phase angle between the primary and secondary voltages. The motor can be used as a speed controlling device or a multifunctional power controlling device in industrial applications and power conversion systems. >

Some Considerations on the Design Method of Parametric Motor Utilizing the Equivalent Circuit

Parametric motors have many excellent features compared with ordinary single-phase motors, and are expected to find many practical applications. In this paper, methods for improving the characteristics of parametric motors in order to render them more practically useful are discussed, utilizing the equivalent circuit of an induction motor. Implementation of such methods results in a parametric motor having excellent performance. Improved power factor, output power, and efficiency are achieved both by increasing the effective magnetic flux through an enlarged rotor diameter and by determining the optimum rotor length. The motor size and weight were reduced by decreasing the dimensions of the magnetic flux path of the exciting core without impairing the motor characteristics.

Some Considerations on the Design Method of a Parametric Motor

The parametric motor has many excellent features compared with ordinary single-phase motors, and is expected to have many practical applications. In this paper, methods of motor design to make such motors more practical are discussed. In particular, the relationship between the motor characteristics and the several dimensions of stators and rotors are investigated. We discovered a method for designing the stator and rotor dimensions which yields the optimum ratio of flux in the stator for parametric oscillation to flux for motor operation.

The Influence That Real-Time Reflection RTR Gives in Co-Creative Activation of the Learner

工学教育(J.of JSEE), 64–4(2016) 1.はじめに 複雑化する社会問題に対し,他者と協力しながら創 造的に問題を解決できる協創性の育成が求められてい る.筆者らは協創性の育成には,学習経験の内省で得 た知識や気づきを他者と共有できる学習環境が必要で あると考え,学習経験の記録をICT(情報通信技術) によってリアルタイムで内省する仕組みRTR-リア ルタイムリフレクションを考案した. RTRは八戸工業大学感性デザイン学科のデザイン 演習を通して実践的に構築された.このデザイン演習 は,青森県おいらせ町の特産品をPRするイベントの 企画とポスターなどの販促ツールをグループワークで デザインする内容であった.筆者らは,RTRの構築に あたりデザインプロセスに必要な知識や技術の情報だ けでなく,グループごとの活動内容を専用ウェブサイ トにリアルタイムでコンテンツ化し,学習者が授業内 外の時間を使って内省できる環境を整えた. 本稿では,RTRによる持続的な内省支援環境におい て,学習者の協創活動がどのように展開したのかにつ いて調査・分析した結果について概説する.