Types of Current's in a transformer... ?

What is Magnetizing Current ?

Magnetizing current is a current component which is seen in electrical machines likes transformers and motors. No load current of transformer has two components, one is the magnetizing component and other is the active component.

Magnetizing component is also called the reactive or wattles component of no-load current. The active component or watt full component supplies the hysteresis and eddy current loses. Magnetizing component of no load current magnetizes the core of the transformer. Thus this component sets up flux in the transformer core.

Magnetizing current is in phase with the flux and is 90 ° to applied voltage and active component. Magnetizing current is associated with the primary winding of the transformer. It is the current that flows in primary when voltage is applied across it and in this condition secondary is unloaded. Magnetizing current value is related to supply voltage, frequency and primary inductance value.
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Primary side always has a current irrespective of the load condition of transformer which is called magnetizing current and this current adds on to the load current. So primary of transformer draws a peak current that is known as magnetizing inrush current. Magnitude of this current is high and it lasts for a very less time and it is transient in nature.
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What is Eddy Current?

Magnetic circuits are subjected to two kinds of losses- these are Hysteresis loss and Eddy current loss. Eddy current is responsible for eddy current loss. Core is composed of conducting materials so that the voltage induced in it by the varying flux produces circulating currents in the iron core. These are called eddy currents and are accompanied by I²R loss in the core. Since eddy current depends upon the rate of change of flux as well as the resistance of the path, eddy current loss varies to the square of both maximum flux density and the frequency. Eddy current loss is given by –

P_e = K_e f² (B_max) ² t²v Watts or joules/second.

K_e is the eddy current coefficient and it depends upon the type of core material, f is the number of complete magnetization cycles per second, B _max is the maximum flux density in Tesla (WB/m²), t is the thickness of laminations in metres and v is the volume of core material in metre cube. To increase the core resistance and thereby minimizing eddy currents, magnetic cores subjected to alternating fluxes are assembled from thin sheets with an insulating layer between successive laminations .
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Eddy currents have a magnetic effect tending to make the flux density at centre lower than at the surface. Hysteresis and eddy current losses taken together are known as core or iron loss.
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