Analysis of two major causes of transformer loss

There are two main reasons for transformer losses:

First, when the primary winding of the transformer is energized, the magnetic flux generated by the coil flows in the iron core. Since the iron core itself is also a conductor, an electric potential is induced on a plane perpendicular to the magnetic force line, and this potential is formed on the cross section of the iron core. The loop is closed and a current is generated, called "eddy current." This "vortex" increases the loss of the transformer, causing the core of the transformer to heat up and the temperature rise of the transformer to increase. The loss caused by the "eddy current" is called "iron loss".

Second, a large number of copper wires are required to wind the transformer. These copper wires have resistance. When the current flows, the resistor consumes a certain amount of power. This loss is often consumed as heat. This loss is called "copper loss."

Therefore, the temperature rise of the transformer is mainly caused by iron loss and copper loss. Since the transformer has iron loss and copper loss, its output power is always less than the input power, and the efficiency η represents the relationship between the output power and the input power: η = output power / input power.