Self-Inductance
Self-inductance is the property of a coil or circuit whereby a changing current induces a voltage in the same circuit. It is a measure of the ability of the coil to oppose changes in current by producing a counter electromotive force (EMF).
Magnetic Circuits with AC Excitation
A magnetic circuit with alternating current (AC) excitation involves a varying magnetic field as the current changes direction periodically. This results in a time-varying magnetic flux, which can induce voltages and create losses due to hysteresis and eddy currents.
Hysteresis Losses
Hysteresis loss occurs in magnetic materials due to the lagging of magnetic flux density (B) behind the magnetic field strength (H) when a material is subjected to an alternating magnetic field. The energy lost during each cycle of magnetization is due to molecular friction within the material.
Eddy Current Losses
Eddy current losses are power losses caused by circulating currents induced in a magnetic material when it is subjected to a changing magnetic field. These currents create heat and reduce the efficiency of devices like transformers and electric motors.
Introduction to Transformer
A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It operates on the principle of Faraday’s Law of Electromagnetic Induction and is used to step up or step down voltage levels in AC circuits.
The Ideal Transformer
An ideal transformer is a theoretical model of a transformer that assumes no losses (such as resistance, eddy current, or hysteresis losses) and perfect magnetic coupling between the primary and secondary windings. It provides 100% efficient energy transfer between coils.
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