Strong electric and magnetic fields

 

 

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The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described by Maxwell’s equations and the Lorentz force law.

 

Magnetic fields are associated with two magnetic poles, north and south, although they are also produced by charges (but moving charges). Like poles repel; unlike poles attract. Electric field points in the direction of the force experienced by a positive charge.

 

Basically, the flow of electricity through a wire creates magnetic fields, and certain types of magnetic fields (they have to change with time) cause the flow of electricity.

 

The small charge is called the test charge. This force can be found using Coulomb’s law. Electric field diagrams are used to depict electric fields. When lines are close together, the field is strong. The electric force is similar to the gravitational force.

 

Coulomb’s law states that: The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them. The force is along the straight line joining them.

 

Since force is a vector, the electric field too is a vector quantity. The electric potential however is not a vector. The electric potential is the amount of electric potential energy that a unitary point electric charge would have if located at any point in space, and energy is a scalar quantity.

 

Conventionally, electric field lines emerge out of a positive charge and sink up at the negative charge. … These lines are assumed to be continuous and travel to infinity, because, their discontinuity would mean that the charge has suddenly vanished and reappears again, which is absurd.

 

 

 

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Cable technology

 

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Electrical cables are used to connect two or more devices, enabling the transfer of electrical signals or power from one device to the other.

 

Electrical cables may be made more flexible by stranding the wires.

 

Any current-carrying conductor, including a cable, radiates an electromagnetic field.

 

Likewise, any conductor or cable will pick up energy from any existing electromagnetic field around it.

 

Electrical wires may be made of copper or aluminum metal, both of which conducts electricity, but copper is a much better conductor than aluminum and a safer option.

 

When electricity flows from one point to another through something like an electrical wire, we call this conductivity.

 

Silver also has the highest thermal conductivity of any element and the highest light reflectance. Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance.

 

 

 

 

 

 

 

 

 

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Power stations, networks and systems

 

 

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An electric power system is a network of electrical components deployed to supply, transfer, store, and use electric power. An example of an electric power system is the grid that provides power to an extended area. Smaller power systems are also found in industry, hospitals, commercial buildings and homes.

 

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines which facilitate this movement are known as a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution.

 

Most transmission lines are high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency over very long distances (typically hundreds of miles).

 

HVDC technology is also used in submarine power cables (typically longer than 30 miles (50 km)), and in the interchange of power between grids that are not mutually synchronized.

 

Electricity is transmitted at high voltages (115 kV or above) to reduce the energy loss which occurs in long-distance transmission. Power is usually transmitted through overhead power lines. Underground power transmission has a significantly higher installation cost and greater operational limitations, but reduced maintenance costs.

 

Electricity generation is the process of generating electric power from sources of primary energy. For electric utilities in the electric power industry, it is the first stage in the delivery of electricity to end users, the other stages being transmission, distribution, energy storage and recovery, using pumped-storage methods.

 

Electricity is most often generated at a power station by electromechanical generators, primarily driven by heat engines fueled by combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. Other energy sources include solar photovoltaics and geothermal power.

 

 

 

 

 

 

 

 

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Safety of electrical equipment

 

 

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It is extremely important to have various safety devices to protect from fire and electrocution. Industrial electricity use has similar problems. This page examines these electrical safety devices. Namely, fuses, circuit breakers, and ground fault circuit interrupters.

 

Circuit breakers protect electrical circuits and appliances. Residual current circuit breakers, RCCBs, protect some circuits. They detect a difference in the current between the live and neutral wires. RCCBs work much faster than fuses do.

 

Personal protective equipment (PPE) refers to protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer’s body from injury or infection. The hazards addressed by protective equipment include physical, electrical, heat, chemicals, biohazards, and airborne particulate matter.

 

Personal protective equipment, commonly referred to as “PPE”, is equipment worn to minimize exposure to a variety of hazards. Examples of PPE include such items as gloves, foot and eye protection, protective hearing devices (earplugs, muffs) hard hats, respirators and full body suits.

 

An RCD, or residual current device, is a life-saving device which is designed to prevent you from getting a fatal electric shock if you touch something live, such as a bare wire. It can also provide some protection against electrical fires.

 

An RCD Safety Switch protects by constantly monitoring the current flowing in theActive and Neutral wires supplying a circuit or an individual item of equipment. Under normal circumstances, the current flowing in the two wires is equal.

 

Safety Switches or RCD’s (Residual Current Devices) provide a fast power cut-off in problem situations. Electrical hazards are often hidden and can be difficult to identify, such as a small hole in an extension lead or a power board damaged internally.

 

 

 

 

 

 

 

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