Electromagnetic induction

1. Electromagnetic induction LC3 Adv.Phy Project Names: Hassan Ali AbdulRahman , Hassan Ali Abdullah , AbdulAzizAbdulRahman .

2. Electromagnetic induction • Electromagnetic induction is the production of voltage across a conductor moving through a magnetic field. It underlies the operation of generators, all electric motors, transformers, induction motors, synchronous motors, solenoids, and most other electrical machines. • Faraday’s stated that electromotive force (EMF) produced around a closed path is proportional to the rate of change of the magnetic flux through any surface bounded by that path. In practice, this means that an electric current will be induced in any closed circuit when the magnetic flux through a surface bounded by the conductor changes. This applies whether the field itself changes in strength or the conductor is moved through it.

3. Induction welding • Induction welding is a form of welding that uses electromagnetic induction to heat the work piece. The welding apparatus contains an induction coil that is energized with a radio-frequency electric current. This generates a high-frequency electromagnetic field that acts on either an electrically conductive or a ferromagnetic work piece. In an electrically conductive work piece, such as steel, the main heating effect is resistive heating, which is due to magnetically induced currents called eddy currents. In a ferromagnetic work piece, such as plastic doped with ceramic particles, the heating is caused mainly by hysteresis as the magnetic component of the electromagnetic field repeatedly distorts the crystalline structure of the ferromagnetic material. In practice, most materials undergo a combination of these two effects. • nonmagnetic materials such as plastics can be induction-welded by implanting them with metallic or ferromagnetic compounds, called susceptors, that absorb the electromagnetic energy from the induction coil, become hot, and lose their heat to the surrounding material by thermal conduction. • Induction welding is used for long production runs and is a highly automated process, usually used for welding the seams of pipes. It can be a very fast process, as a lot of power can be transferred to a localized area, so the faying surfaces melt very quickly and can be pressed together to form a continuous rolling weld.

4. Induction welding

5. Transformer • A transformer is a static device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or "voltage" in the secondary winding. This effect is called mutual induction.

6. Transformer