Transformers

crystalbrite

Can anyone tell me what the magnetizing inductance in an ideal transformer does or what it is used for? Its the one that is parallel to the primary or secondary winding.

2011

It is in parallel with the windings. This represents the finite permeability of the iron core of the transformer.

crystalbrite

Sorry, but that still dosnt make much sense to me

2011

Can anyone tell me what the magnetizing inductance in an ideal transformer does or what it is used for?

First off no transformer is "ideal" but by treating the transformer as ideal and representing its various losses as inductors and resistors connected to it, calculations can be made much less complex. They are broken into 2 groups, iron losses and copper losses

Copper Losses

An inductor drawn in series with the primary side represents the leakage flux on the primary, and an inductor is drawn on the secondary side (again in series with the secondary windings) to represent the leakage flux on the secondary side.

Resistors are also drawn dawn in series with the windings on each side to represent the resistance of the windings on each side. Due to the fact that they are in series with the windings this loss is directly proportional to the current.

Iorn Losses

A magnetising current is required to set up a magnetic flux in the core. This current is constant regardless of the load on the transformer. It is made up of 2 components:

1) This part of the current magnetises the core. The impedance that it meets is represented by an inductor that is connected in parellel with the core. This is the one you were referring to.

2) This component of the current is a loss due to hysteresis and eddy current loss in the core. The resistance that this current meets is represented by a resistor in parellel with the windings. It is this part of the current that causes transformers to heat.

Copper losses vary with the load applied to the transformer. Iron (or core) losses remain constant regardless of the load.


As part of an electrical engineering degree students sometimes given a trnasfomer and asked to calculate the values of the components mentioned above. Would this be you?

crystalbrite

Ya im studying an electrical engineering degree and thanks, i'm starting to understand it better now

2011

No bother.