Cars, buses and more running on electric power
An electric vehicle (EV), also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion. An electric vehicle may be powered through a collector system by electricity from off-vehicle sources, or may be self-contained with a battery or generator to convert fuel to electricity. EVs include road and rail vehicles, surface and underwater vessels, electric aircraft and electric spacecraft.
EVs first came into existence in the mid-19th century, when electricity was among the preferred methods for motor vehicle propulsion, providing a level of comfort and ease of operation that could not be achieved by the gasoline cars of the time. The internal combustion engine (ICE) has been the dominant propulsion method for motor vehicles for almost 100 years, but electric power has remained commonplace in other vehicle types, such as trains and smaller vehicles of all types.
Computer programs useful in electrical
Electrical installations, especially those which will be installed in buildings with complicated structures often require the creation of a very difficult project. Special computer programs enable electricians much easier to plan where and how they will run the wire, where will be located branch and so on. In this way, more and more electricians may remind us of specialists, because the design of electrical networks at the present time is done properly only through the computer. Special programs also allow control of parameters during operation of the installation.
Power cables and their history
Early telegraph systems used the first forms of electrical cabling, transmitting tiny amounts of power. Gutta-percha insulation used on the first submarine cables was, however, unsuitable for building wiring use since it deteriorated rapidly when exposed to air.
The first power distribution system developed by Thomas Edison in 1882 in New York City used copper rods, wrapped in jute and placed in rigid pipes filled with a bituminous compound. Although vulcanized rubber had been patented by Charles Goodyear in 1844, it was not applied to cable insulation until the 1880s, when it was used for lighting circuits. Rubber-insulated cable was used for 11,000 volt circuits in 1897 installed for the Niagara Falls power project.
Mass-impregnated paper-insulated medium voltage cables were commercially practical by 1895. During World War II several varieties of synthetic rubber and polyethylene insulation were applied to cables.
Typical residential and office construction in North America has gone through several technologies:
Early bare and cloth-covered wires installed with staples
Knob and tube wiring, 1880s-1930s, using asphalt-saturated cloth or later rubber insulation
Armored cable, known by the genericized trademark "Bx" - flexible steel sheath with two cloth-covered, rubber-insulated conductors - introduced in 1906 but more expensive
Rubber-insulated wires with jackets of woven cotton cloth (usually impregnated with tar), waxed paper filler - introduced in 1922
Early two-wire PVC-insulated cable, known by the genericized trademark "Romex", 1950s
Aluminum wire was used in the 1960s and 1970s as a cheap replacement for copper, but this is now considered unsafe due to corrosion
Asbestos was used as an Insulator (electricity) in some cloth wires from the 1920s to 1970s.
Modern three-wire PVC-insulated cable, also known as "Romex" - see thermoplastic-sheathed cable