A New Type Brushless DC Rate Generator

1989 ◽  
Vol 109 (9) ◽  
pp. 693-693
Author(s):  
Hideomi Sekine ◽  
Masakazu Mizuide ◽  
Kazuhiko Suto ◽  
Tsugumasa Suto
Keyword(s):  
Brushless Dc ◽  
New Type

scholarly journals Computer Aided Modeling and Analysis of Five-Phase PMBLDC Motor Drive for Low Power High Torque Application

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
M. A. Inayathullaah ◽  
R. Anita
Keyword(s):  
Low Power ◽  
High Efficiency ◽  
Dynamic Performance ◽  
Torque Ripple ◽  
Performance Simulation ◽  
Modeling And Analysis ◽  
Brushless Dc ◽  
New Type ◽  
High Torque ◽  
Permanent Magnet Brushless Dc

In order to achieve high torque at low power with high efficiency, a new five-phase permanent magnet brushless DC (PMBLDC) motor design was analyzed and optimized. A similar three-phase motor having the sameD/Lratio (inner diameter (D) and length of the stator (L)) is compared for maximum torque and torque ripple of the designed five-phase PMBLDC motor. Maxwell software was used to build finite element simulation model of the motor. The internal complicated magnetic field distribution and dynamic performance simulation were obtained in different positions. No load and load characteristics of the five-phase PMBLDC motor were simulated, and the power consumption of materials was computed. The conformity of the final simulation results indicates that this method can be used to provide a theoretical basis for further optimal design of this new type of motor with its drive so as to improve the starting torque and reduce torque ripple of the motor.

A New Type of Brushless DC Motor Control Strategy

2014 ◽  
Vol 986-987 ◽  
pp. 1031-1034
Author(s):  
Xiao Lei Zhang ◽  
Kui Hua Wu ◽  
Jian Wang ◽  
Wei Sun ◽  
Kui Zhong Wu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Torque Ripple ◽  
Dc Motor ◽  
Brushless Dc Motor ◽  
Energy Feedback ◽  
Brushless Dc ◽  
Dc Motor Control ◽  
New Type ◽  
Set Up ◽  
Small Torque

Because torque ripple disturbance can be created when the brushless dc motor is communicating, In this paper, from two aspects of energy feedback and the torque ripple, H/L - PWM - ON control strategy is analyzed .And a simulation system is set up. Through the trials, it shows that H/L - PWM - ON strategy can efficiently complete the energy feedback, has small torque ripple, and fully proves the feasibility and practicability of this control strategy.

Development of a Segmented Linear Variable Flux Reluctance Motor with DC-Field Coil

2013 ◽  
Vol 416-417 ◽  
pp. 203-208
Author(s):  
Di Wu ◽  
Z.Q. Zhu ◽  
Robert Nilssen
Keyword(s):  
Maximum Efficiency ◽  
Element Analysis ◽  
Average Force ◽  
Brushless Dc ◽  
Copper Loss ◽  
Reluctance Motor ◽  
New Type ◽  
Force Ripple ◽  
Multi Phase ◽  
Variable Flux

This paper proposes a new type of linear motor based on the concept of variable flux reluctance motor (VFRM). By adopting segmented primary stator, the segmented linear VFRM (SLVFRM) can eliminate asymmetry between phases due to end-effect. Meanwhile, multi-phase SLVFRM of any number of phases can be obtained by adjusting number of segments directly. The stator/mover tooth pitch combination and segments arrangement rules are also illustrated. An optimized 3-phase SLVFRM is analyzed by finite element analysis, with focus on characteristics such as cogging force, back-EMF and winding inductances. Further, both brushless AC (BLAC) and brushless DC (BLDC) drive for SLVFRM are investigated. Besides much smaller force ripple, BLDC drive can obtain higher average force at same RMS current due to trapezoidal back-EMF. The force characteristicwith variousAC and DC currents and current angles are also investigated in the paper, and it shows that SLVFRM has negligible reluctance force while keeping the same AC and DC currents is optimal for maximum efficiency operation under a fixed copper loss.

The Microstructure of Shock-Synthesized Diamond

1967 ◽  
Vol 25 ◽  
pp. 324-325
Author(s):  
Lucien F. Trueb
Keyword(s):  
Single Crystals ◽  
Preferred Orientation ◽  
High Magnification ◽  
Texture Pattern ◽  
Shock Process ◽  
New Type ◽  
Diffraction Diagram

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.

New type electron gun with electrostatic and electromagnetic lenses

1978 ◽  
Vol 36 (1) ◽  
pp. 62-63
Author(s):  
T. Ichinokawa ◽  
H. Maeda
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Optimum Condition ◽  
Bias Voltage ◽  
Electron Gun ◽  
Charge Effect ◽  
Micro Fabrication ◽  
Maximum Brightness ◽  
New Type ◽  
The Ideal

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

Trial production of γ-type energy filtering TEM

1995 ◽  
Vol 53 ◽  
pp. 604-605
Author(s):  
Y. Taniguchi ◽  
E. Nakazawa ◽  
S. Taya
Keyword(s):  
Magnetic Energy ◽  
Electron Optics ◽  
Electron Microscopic ◽  
Mass Spectrometers ◽  
Ion Optics ◽  
Energy Filtering ◽  
New Information ◽  
New Type ◽  
Fringing Fields

Imaging energy filters can add new information to electron microscopic images with respect to energy-axis, so-called electron spectroscopic imaging (ESI). Recently, many good results have been reported using this imaging technique. ESI also allows high-contrast observation of unstained biological samples, becoming a trend of the field of morphology. We manufactured a new type of energy filter as a trial production. This energy filter consists of two magnets, and we call γ-filter since the trajectory of electrons shows ‘γ’-shape inside the filter. We evaluated the new energyγ-filter TEM with the γ-filter.Figure 1 shows schematic view of the electron optics of the γ-type energy filter. For the determination of the electron-optics of the γ-type energy filter, we used the TRIO (Third Order Ion Optics) program which has been developed for the design of high resolution mass spectrometers. The TRIO takes the extended fringing fields (EFF) into consideration. EFF makes it difficult to design magnetic energy filters with magnetic sector fields.

Development of imaging plate for a TEM and its characteristics

1989 ◽  
Vol 47 ◽  
pp. 100-101
Author(s):  
N. Mori ◽  
T. Oikawa ◽  
Y. Harada ◽  
J. Miyahara ◽  
T. Matsuo
Keyword(s):  
Dynamic Range ◽  
Protective Layer ◽  
High Sensitivity ◽  
Imaging Plate ◽  
Phosphor Layer ◽  
Imaging Device ◽  
X Ray Imaging ◽  
New Type ◽  
Basic Characteristics ◽  
Reading System

The Imaging Plate (IP) is a new type imaging device, which was developed for diagnostic x ray imaging. We have reported that usage of the IP for a TEM has many merits; those are high sensitivity, wide dynamic range, and good linearity. However in the previous report the reading system was prototype drum-type-scanner, and IP was also experimentally made, which phosphor layer was 50μm thick with no protective layer. So special care was needed to handle them, and they were used only to make sure the basic characteristics. In this article we report the result of newly developed reading, printing system and high resolution IP for practical use. We mainly discuss the characteristics of the IP here. (Precise performance concerned with the reader and other system are reported in the other article.)Fig.1 shows the schematic cross section of the IP. The IP consists of three parts; protective layer, phosphor layer and support.

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