Efficiency of the transformer

When the transformer output power equal to the input power P1, P2, the efficiency η is equal to 100%, the transformer will not produce any loss. But in fact this transformer is not. The total transmission power transformer to generate losses, these losses are mainly copper and iron losses. Electric energy meter winding copper loss is the loss caused by resistance. When the current through the coil resistance heating, a part of the electrical energy into heat energy loss. Since the coil general by air circuit breaker copper wire wound together, so called copper loss.
Of the iron loss in two ways. First, the hysteresis loss, when the AC current through the transformer, the transformer magnetic flux silicon and size change with the direction, so that silicon internalcircuit breakers, heat release, thus loss of a portion of electrical energy, which is hysteresis loss . Another is the eddy current loss, when the transformer work. A magnetic core in the line through, with the plane perpendicular to the magnetic field lines will generate induced currents, due to this current is formed from a closed circulation circuit, and a spiral-shaped, so called vortex. The presence of vortex core heat, consume energy, this loss is called eddy current loss.
Efficiency of the transformer and the transformer power levels are closely related, usually greater the power loss and the output power ratio is smaller, the higher the efficiency. Conversely, the smaller the power, the lower the efficiency.