Why Are Transformer Inductance and Capacitance Modeled in Parallel?

[Jacky]

Here is my question.

It is rather simple quetion. But I am a beginer in this field so please help me.

In the case of equivalent ciruit of the tranformer it is taken that the inductance and the capacitance in the primary coil of the transformer is taken parrallel and the inductance and capacitance of the secondary coil tranfered to the primary are taken parrallel. Could you please explain to me the actual reason behind it?

 

[stewartcs]

Here is my question.

It is rather simple quetion. But I am a beginer in this field so please help me.

In the case of equivalent ciruit of the tranformer it is taken that the inductance and the capacitance in the primary coil of the transformer is taken parrallel and the inductance and capacitance of the secondary coil tranfered to the primary are taken parrallel. Could you please explain to me the actual reason behind it?

Generally speaking, equivalent circuits are used to simplify a complex circuit into terms that are solvable with known relations. For example, in a transformer equivalent circuit you can account for winding losses and flux leakage with a series resistance and reactance on the primary side. Core losses can be modeled similarly with a parallel resistance and reactance on the primary also.

Essentially when reflecting/referring an impedance to the primary side of a transformer, you are just seeing what the secondary impedance "looks like" to the primary side. Since the secondary impedance will determine the load on the primary, it is helpful to know how to relate it in terms of the primary so as to calculate the current flow in the primary due to the load on the secondary.

Hope that helps.

CS