scholarly journals A Direct-Current Generator for Constant Potential at Variable Speed

1918 ◽  
Vol XXXVII (2) ◽  
pp. 1405-1415
Author(s):  
S. R. Bergman
Keyword(s):  
Direct Current ◽  
Variable Speed ◽  
Current Generator ◽  
Constant Potential

scholarly journals Variable-Speed Engines on Wind Farm Support Vessels

2020 ◽  
Vol 8 (3) ◽  
pp. 229 ◽  
Author(s):  
Kristian Eikeland Holmefjord ◽  
Lars Husdal ◽  
Martijn de Jongh ◽  
Sverre Torben
Keyword(s):  
Direct Current ◽  
Diesel Engines ◽  
Wind Farm ◽  
East Coast ◽  
Frequency Converter ◽  
Real Life ◽  
Alternating Current ◽  
Variable Speed ◽  
Fixed Frequency ◽  
Fuel Savings

We examine the fuel savings of Edda Passat, a newly constructed wind farm support vessel that utilizes a common direct current (DC) grid. This enables its diesel engines to operate at variable speeds by using frequency converter technology. A detailed investigation of these benefits has been performed based on real-life measurements from three months of operations in the Race Bank wind farm off the east coast of England. The calculated fuel savings of Edda Passat achieved via its variable-speed engines are 21% lower compared to using a conventional alternating current (AC) grid with a fixed frequency. This paper will explain the technology, measurements, and results in detail.

scholarly journals Direct-Current Generator Based on Dynamic PN Junctions with the Designed Voltage Output

iScience ◽  
2019 ◽  
Vol 22 ◽  
pp. 58-69 ◽  
Author(s):  
Yanghua Lu ◽  
Zhenzhen Hao ◽  
Sirui Feng ◽  
Runjiang Shen ◽  
Yanfei Yan ◽  
...  
Keyword(s):  
Direct Current ◽  
Current Generator ◽  
Voltage Output ◽  
Pn Junctions

The use of diamond-impregnated tools for rock-slicing

1950 ◽  
Vol 29 (210) ◽  
pp. 191-199
Author(s):  
K. C. Dunham ◽  
J. T. Taylor
Keyword(s):  
Direct Current ◽  
Rock Specimen ◽  
Hard Rock ◽  
Diamond Powder ◽  
Variable Speed ◽  
Training Centre ◽  
Standard Practice ◽  
Geological Museum ◽  
Normal Speed ◽  
The Government

For the cutting of chips from rocks preparatory to thin-slicing, it has been standard practice for many years to use notched soft iron disks, manually armed with diamond powder. The latest machines employing cutting-disks of this type at the Geological Museum were built at the Government Training Centre, Ascot Works, Letchworth, to the design of the late Dr. H. H. Thomas and of Mr. W. Ward of the Centre. These are powered with 0.25 horse-power variable speed direct current motors, giving a maximum disk speed of 280 revolutions per minute. By means of rheostats, control of speed as sensitive as that obtainable with a treadle type of machine (see A. V. Weatherhead) is achieved. The normal speed for cutting is 160 to 180 r.p.m. In cutting a hard rock such as chert, it may be necessary to recharge the disk with diamond several times during the operation. The rock-specimen is held in a steel clamp with hardwood liners, mounted on a swinging arm. The rock is held in contact with the disk by the tension of a spring, or, during delicate work, by the pressure of the hand.

DC-link project applied to Variable Speed Drives in Subsea Power Systems

2020 ◽  
Author(s):  
Daniel Krejci ◽  
João Adolpho V. da Costa ◽  
Diego De S. de Oliveira ◽  
Gustavo Cezimbra B. Leal ◽  
Emanuel L. van Emmerik ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Direct Current ◽  
Entire System ◽  
Variable Speed ◽  
Variable Speed Drives ◽  
Electromagnetic Transient ◽  
Project Method ◽  
Power Electronics Converters ◽  
And Inversion

This paper presents a project method of the direct current link in order to decouple the rectification and inversion stages present in power electronics converters in a subsea power system, showing the calculation memories of the capacitors to be used in Variable Speed Drives that drive subsea loads. In order to observe the influence of harmonics on the subsea power system and on the voltage of the direct current link, the entire system was modeled with the PSCAD/EMTDC electromagnetic transient software.

A High Voltage Direct Current Generator

1932 ◽  
Vol 42 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Richard E. Vollrath
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Current Generator ◽  
High Voltage Direct Current
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