Electromagnetic Induction

Electromagnetic induction

Electromagnetic induction is the symptom of an electric current in a conductor due to changes in the magnetic field around the conductor wire. Electromagnetic induction can arise if a magnet is moved closer to and away from the coil. Changes may occur if the magnetic field inside the coil magnet is moved for example on a bicycle dynamo, driven coil in a magnetic field generator for example, and a coil connected to the alternating current example in the transformer. Induction currents can be enlarged in a way, which uses coils with coils more and more, using a strong magnet, soft iron core entering into coils, and rotate the coil faster.According to Faraday, an electrical current can be generated by moving the magnet out of the coil. This finding applied to an electric generator which converts mechanical energy into electrical energy. Some examples of tools that use the working principle of electromagnetic induction as follows.1. TransformerThe transformer (transformer) is a tool to increase or decrease the power supply voltage alternating current which is based on the principle of induction elektromagnetik.Tranformator lowering voltage "step-down transformer, while the step-up voltage transsformator" trafao step up. The transformer is basically composed of the primary winding and the secondary winding is connected using an iron core. The primary winding receiving AC voltage induces an iron core to be a magnet. AC current direction changes create a magnetic field is formed to change, resulting in an AC voltage at the ends of the secondary coil.

The size of the resulting output voltage transformer is strongly influenced by the number of turns on the primary and secondary coils. If the number of primary windings more than the number of secondary windings, the voltage on the secondary coil will also be smaller than the voltage on the secondary coil, and the transformer is called a step-down transformer. However, if the number of primary windings fewer than the number of secondary windings, the voltage on the secondary coil will be greater than the voltage on the primary coil, and the transformer is called a step-up transformer.

In an ideal transformer, electrical energy that goes into the primary coil is moved entirely into the secondary coil. This resulted in great efficiency transformers to 100% or mathematically expressed as follows.

In fact, never be made transformer with an efficiency of 100%, since usually the majority of electrical energy into the primary coil is converted into heat. Thus, the electrical energy entering the primary coil is always greater than the energy that comes out in the secondary coil. As a result, primary power is greater than the secondary power. Reduced power and electrical energy in a transformer is determined by the size of the transformer efficiency. Calculation of transformer efficiency (η), which is not ideal can be done by using the following formula.

Sample Problem Transformer
A transformer has 300 primary winding and a secondary winding 30. If the voltage on the primary winding is 220 volts, specify:

     The voltage on the secondary windings
     If the electric current flowing in the primary winding of 0.5 mA, what is the electric current flowing in the secondary winding?
     efficiency transformers
     type transformer


Is known:
Np = 300 winding
Ns = 30 windings
Vp = 220 volts
Ip = 0.5 mA
asked:

     Secondary voltage (Vs)
     Secondary current (Is)
     Transformer efficiency (η)
     type transformer

Note: in everyday life there is no transformer efficiency of 100%

d. Because Vp> Vs and Np> Ns then the transformer is a step-down transformer.

2. Generator
Generator is a tool used to change the energy of motion (kinetic) into electrical energy. Energy generator of movement that can be obtained from a variety of alternative energy sources, such as from wind energy, water energy, and so on. Generator generator can be divided into AC (Alternating Current) and generator DC (Direct Current). AC generator or alternator can produce alternating electrical current by using the double ring, while the DC generator can generate electric current by using a commutator (split ring).

 3. Dinamo AC-DC
Dinamo is a relatively small generators such as those used on the bike. The workings of the dynamo and the generator is almost the same, including the use of one ring that is split into two (commutator) on the armature DC and AC double ring on the armature. The difference lies in the dynamo generator dynamo two main components, namely the rotor (no moving parts) and the stator (stationary part).
                                               by:abu

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