Editing Transformer (section)

====Deviations from ideal transformer====
The ideal transformer model neglects many basic linear aspects of real transformers, including unavoidable losses and inefficiencies.<ref>{{cite book|isbn=0-03-061758-8|title=Electrical Engineering: An Introduction|publisher=Saunders College Publishing|year=1984|page=610}}</ref>

(a) Core losses, collectively called magnetizing current losses, consisting of<ref name="Say1983"/>
* [[Magnetic hysteresis|Hysteresis]] losses due to nonlinear magnetic effects in the transformer core, and
* [[Eddy current]] losses due to joule heating in the core that are proportional to the square of the transformer's applied voltage.

(b) Unlike the ideal model, the windings in a real transformer have non-zero resistances and inductances associated with:
* [[Joule heating|Joule losses]] due to resistance in the primary and secondary windings<ref name="Say1983"/>
* Leakage flux that escapes from the core and passes through one winding only resulting in primary and secondary reactive impedance.

(c) similar to an [[inductor]], parasitic capacitance and self-resonance phenomenon due to the electric field distribution. Three kinds of parasitic capacitance are usually considered and the closed-loop equations are provided<ref>L. Dalessandro, F. d. S. Cavalcante, and J. W. Kolar, "Self-Capacitance of High-Voltage Transformers," IEEE Transactions on Power Electronics, vol. 22, no. 5, pp. 2081–2092, 2007.</ref>
* Capacitance between adjacent turns in any one layer;
* Capacitance between adjacent layers;
* Capacitance between the core and the layer(s) adjacent to the core;

Inclusion of capacitance into the transformer model is complicated, and is rarely attempted; the [[#Real transformer equivalent circuit figure|'real' transformer model's equivalent circuit shown below]] does not include parasitic capacitance. However, the capacitance effect can be measured by comparing open-circuit inductance, i.e. the inductance of a primary winding when the secondary circuit is open, to a short-circuit inductance when the secondary winding is shorted.