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Electromagnetic induction

Electromagnetic induction
Electromagnetic induction is the production of a potential difference (voltage) across a conductor when it is exposed to a varying magnetic field. It is described mathematically by Faraday's law of induction, named after Michael Faraday who is generally credited with the discovery of induction in 1831. History[edit] A diagram of Faraday's iron ring apparatus. Electromagnetic induction was discovered independently by Michael Faraday and Joseph Henry in 1831; however, Faraday was the first to publish the results of his experiments.[2][3] In Faraday's first experimental demonstration of electromagnetic induction (August 29, 1831[4]), he wrapped two wires around opposite sides of an iron ring or "torus" (an arrangement similar to a modern toroidal transformer). Faraday explained electromagnetic induction using a concept he called lines of force. Faraday's law and the Maxwell–Faraday equation[edit] where is the electromotive force (EMF) and ΦB is the magnetic flux. the EMF on a wire loop is: Related:  DIY Clean Energy

Alternator In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines. An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. History[edit] Alternating current generating systems were known in simple forms from the discovery of the magnetic induction of electric current in the 1830s. Principle of operation[edit] Diagram of a simple alternator with a rotating magnetic core (rotor) and stationary wire (stator) also showing the current induced in the stator by the rotating magnetic field of the rotor. The rotating magnetic field induces an AC voltage in the stator windings. An automatic voltage control device controls the field current to keep output voltage constant. In short, a conductor moving relative to magnetic field has an induced EMF in it(Faraday's Law).

Synchronous motor A synchronous motor-generator set for AC to DC conversion. Small synchronous motor and integral stepdown gear from a microwave oven Synchronous motors are available in sub-fractional self-excited sizes[2] to high-horsepower industrial sizes.[1] In the fractional horsepower range, most synchronous motors are used where precise constant speed is required. These machines are commonly used in analog electric clocks, timers and other devices where correct time is required. Type[edit] There are two major types of synchronous motors depending on how the rotor is magnetized: non-excited and direct-current excited.[3] Non-excited motors[edit] Single-phase 60 Hz 1800 RPM synchronous motor for Teletype machine, non-excited rotor type, manufactured from 1930-1955. In non-excited motors, the rotor is made of steel. Reluctance motors[edit] Reluctance motor designs have ratings that range from fractional horsepower (a few watts) to about 22 kW. Hysteresis motors[edit] Permanent magnet motors[edit] where, Here,

Radial Air core alternator Radial Air core alternator Fun! These are simple radial air core alternators that anyone with a drill and jig saw can build. Below are the basic parts for a single magnet 3 phase alternator... 2 plastic triangles sized to match the width of the magnet your using, 1 magnet, some small wooden dowl, 2 1/4" round steel stock ( cut bolts work well ), and some 1/4" bar stock that closely matches the thickness and width of the magnet your using. Next you'll wind 3 coils that will fit around the frame... I used 100 turns of #28 wire as an experiment and it worked pretty well but you can adjust the amount of turns you want based on the voltage you need. Lay the 3 coils over the triangles and tape the coils together. Below is a picture of the completed unit... It easily lights LED's as well has the ability to charge nicad batteries... give it a spin ! Want more? Here is a shot of the parts you'll need to make... The layout and drilling is easy if you make a pattern and tape it to the plastic.

Induction generator An induction generator or asynchronous generator is a type of AC electrical generator that uses the principles of induction motors to produce power. Induction generators operate by mechanically turning their rotor faster than the synchronous speed. A regular AC asynchronous motor usually can be used as a generator, without any internal modifications. Induction generators are useful in applications such as mini hydro power plants, wind turbines, or in reducing high-pressure gas streams to lower pressure, because they can recover energy with relatively simple controls. An induction generator must be excited with a leading voltage. This is usually done by connection to an electrical grid; sometimes, however, they are self-excited by using phase correcting capacitors. Principle of operation[edit] Induction generators and motors produce electrical power when their rotor is turned faster than the synchronous speed. Excitation[edit] Equivalent circuit of induction generator Active power[edit]

Transformer A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Electromagnetic induction produces an electromotive force across a conductor which is exposed to time varying magnetic fields. Commonly, transformers are used to increase or decrease the voltages of alternating current in electric power applications. Since the invention of the first constant potential transformer in 1885, transformers have become essential for the transmission, distribution, and utilization of alternating current electrical energy.[3] A wide range of transformer designs are encountered in electronic and electric power applications. Transformers range in size from RF transformers less than a cubic centimeter in volume to units interconnecting the power grid weighing hundreds of tons. Basic principles[edit] Ideal transformer[edit] Ideal transformer equations (eq.) By Faraday's law of induction . . . (1)[a] Combining ratio of (1) & (2) Turns ratio

Electric generator U.S. NRC image of a modern steam turbine generator The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators have many similarities. History[edit] Before the connection between magnetism and electricity was discovered, electrostatic generators were used. Because of their inefficiency and the difficulty of insulating machines that produced very high voltages, electrostatic generators had low power ratings, and were never used for generation of commercially significant quantities of electric power. In 1827, Hungarian Anyos Jedlik started experimenting with the electromagnetic rotating devices which he called electromagnetic self-rotors, now called the Jedlik's dynamo. Faraday disk, the first electric generator. In the years of 1831–1832, Michael Faraday discovered the operating principle of electromagnetic generators. Electromagnetic generators[edit] Dynamo[edit] Alternator[edit] Induction generator[edit] MHD generator[edit]

How to Build Your Own Uninterruptible Power Supply Edit Article Edited by Evildave, Brandywine, Jonathan E., MBD123 and 15 others In the event of extended blackout, you may have critical systems (such as computer or medical equipment) that must remain running no matter what. Most uninterrupted power supplies sold for computers 'switch' power, running a small inverter when power is interrupted, then switching back to 'normal' power when it's back on. Ad Steps 1Read all warnings before proceeding. 13Supplement alternatives where beneficial or necessary. Warnings Do not wear watches or jewelry when working on the batteries.Wear eye protection when working on batteries.Grounding the inverter is not optional, it is a must.

Armature (electrical engineering) A DC armature. In electrical engineering, an armature generally refers to one of the two principal electrical components of an electromechanical machine — generally in a motor or generator — but it may also mean the pole piece of a permanent magnet or electromagnet, or the moving iron part of a solenoid or relay. The other component is the field winding or field magnet. The role of the "field" component is simply to create a magnetic field (magnetic flux) for the armature to interact with, thus the field component can comprise either permanent magnets, or electromagnets formed by a conducting coil. The armature, in contrast, must carry current so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque (rotating machine), or force (linear machine). In the armature, an electromotive force is created by the relative motion of the armature and the field. In a DC machine, the main field is produced by field coils.

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