Electric traction

River RR operators from the elements. of electric traction on radways. 

Electric traction power in railways offers three significant advantages diversity of fuels, easier control of pollution, and high tractive effort per unit of train weight. Because electricity can be generated by a wide... 

Railway electric traction systems use either ac or direct current (dc). Third rail systems operate on dc at 600 to 700 V. Overhead systems can be found with either 1,500 or 3,000 V dc, or using ac at a range of voltages (from 11,000 to 50,000) and frequencies (16 2/3 to 60 Hz). The modern standard for overhead catenai y systems is usually 25,000 V and cither 50 nr 60 Hz depending on the industrial standard for the country (50 Hz for most of Europe, 60 Hz for the United States and Japan). 

Drainage (electric drainage) (a) flow of positive current through the soil or the electrolyte solution from the cathodically protected structure to the groundbed of the impressed current system, or (b) protection of an immersed structure from electrochemical corrosion by making an electrical connection between the structure and the negative return circuit (rail, feeder, busbar) of a d.c. electric traction system. 

Electric Drainage means of electric protection of an underground system against the corrosive action of stray currents arising from a d.c. electric traction system employing one or more connections (drainage bonds) made between the system to be protected and the return circuit of the traction system (rail, return current feeder, negative busbar of the sub-stations). 

Harmonic number (h) refers to the individual frequency elements that comprise a composite waveform. For example, h = 5 refers to the fifth harmonic component with a frequency equal to five times the fundamental frequency. If the fundamental frequency is 60 Hz, then the fifth harmonic frequency is 5 x 60, or 300 Hz. The harmonic number 6 is a component with a frequency of 360 Hz. Dealing with harmonic numbers and not with harmonic frequencies is done for two reasons. The fundamental frequency varies among individual countries and applications. The fundamental frequency in the U.S. is 60 Hz, whereas in Europe and many Asian countries it is 50 Hz. Also, some applications use frequencies other than 50 or 60 Hz for example, 400 Hz is a common frequency in the aerospace industry, while some AC systems for electric traction use 25 Hz as the frequency. The inverter part of an AC adjustable speed drive can operate at any frequency between zero and its full rated maximum frequency, and the fundamental frequency then becomes the frequency at which the motor is operating. The use of harmonic numbers allows us to simplify how we express harmonics. The second reason for using harmonic numbers is the simplification realized in performing mathematical operations involving harmonics. 

Dawson s "Engineering" and Electric Traction Pocket-book. x6mo, morocco, 4 00... 

Europe s first fuel cell bus, the Eureka, made its much-delayed debut in Brussels near the end of 1994. First announced in 1988, the Eureka was an articulated 59-foot 80-passenger device whose fuel cell and other components were housed in a two-wheeled trailer almost as long as the bus itself. A hybrid with an 87-kilowatt alkaline fuel cell made by the Belgian Elenco company plus NiCad batteries from French battery maker SAFT, it had electrical traction equipment from Italy s Ansaldo and a liquid-hydrogen fuel system contributed by Air Products of the Netherlands. The bus itself came from Van Hool. In all, the partners and the member governments spent about 8 million to get the bus on the road before its demise a few months later. Elenco was forced into bankruptcy in the spring of 1995 when the shareholders refused to come up with additional cash its assets... 

There are several reasons why fuel cells are unlikely to make it as power plants for automobiles any time soon, BMW engineer Christoph Huss asserted in his paper. For one thing, he explained, an electric traction motor for a fuel cell vehicle costs as much as a normal internal-combustion engine. 

Lead accumulators are used in various applications, such as starters of internal combustion engines, electric traction (forklifts, wheelchairs, etc.), power generation units (power plants, telephone exchange stations, railroads, hospitals, etc.). 

In the laboratories of the agricultural equipment manufacturers Allis-Chalmers, a new version of fuel cell with immobilized alkaline electrolyte solution was developed. The company reequipped one of its tractors to electric traction with an electric motor powered by four batteries consisting of 252 alkaline fuel cells each. The traction was strong enough for a load of 3000 pounds. This tractor was a successful demonstration exhibited on different agricultural fairs in the United States. 

To give a general idea, at the end of the eighteenth century, vehicles without horses were divided into three types 407.. steam vehicles, 39% electric traction vehicles and only 227o combustion engine vehicles. 

The ongoing American Fuel Cell Bus (AFCB) project (discussed in Section 3.2.1) will demonstrate an improved ISE electric traction and power electronics system, featuring UTC FCs (120 kW) and the compact high-power EnerDel OB, in a lighter and quieter New Flyer 40-foot bus. This FCB architecture was deployed in 20 FC hybrid buses for the Vancouver 2010 Winter Olympics and has also been used for the London 2012 Summer Olympics. 

Stop start Electric Traction Regenerative Braking Electric Driving Only External Battery Oiarge... 

The first underground railway in the world was opened on January 10,1863 in the City of London, operating with steam locomotives. The first line with electric traction and a three-rail system was built in 1890. The four-rail system, still in use today and consisting of two insulated conductor rails and two running rails, was introduced in 1903 in the course of electrification of the old steam tracks. The Metropolitan Company, responsible for a part of the track, used ac, while the District Railway preferred dc as a consequence of the connection with the American railways. This dispute came before a British arbitration tribunal in 1900. The problem of corrosion of public supply lines by the returning current fi om electric train... 

In rail transport, the basic structure of a raihray train has not changed it is stUl a heavy, massive tractor engine that tows a number of containers on very low friction wheel-systems. The engines have changed from steam-powered behemoths made up of as many as one-quarter-million parts to the modern diesel-electric traction engines of much simpler design. 

Electric-traction system (Frank J. Sprague) Sprague s motor can propel a tram up a steep hill without its slipping. 

Lately the importance of the energy carrier function has considerably increased. The point is to develop power sources of a high specific energy density in the lowest power range for microelectronics as well as in high power ranges for electric traction. 

New Power Sources for Electric Traction and Load Leveling... 

Today the internal combustion engine reigns supreme Virtually all road transport, sea transport and aviation are dependent upon it. Only in the field of railways is there a viable alternative (electric traction) and even there electrification is by no means complete because of capital cost considerations. The overwhelming predominance of the internal combustion engine (including gas turbine in aviation) is associated with a total dependence on petroleum-derived fuels for our transport requirements. 

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