What Is Copper Loss?

Copper loss is the power consumed by the resistance of the primary and secondary windings when the current passes through the primary and secondary windings of the transformer. Copper loss is also called variable loss. As long as the current of the primary and secondary windings is kept constant, the measured copper loss is constant loss. ^[1]

Transformer copper loss is the power consumed by the resistance of the primary and secondary windings when the current passes through the primary and secondary windings. Since PCu is related to I2, the copper loss is also called variable loss. As long as the current of the primary and secondary windings is kept constant, the measured copper loss is constant loss. ^[1]

When the transformer is running at no load, the magnitude of the main magnetic flux in the core is determined by the winding end voltage. Therefore, when the rated voltage is applied to the primary (or secondary) side of the transformer, the main magnetic flux in the iron core reaches the value when the transformer is rated to work. At this time, the power loss (iron loss) in the iron core also reaches the transformer rating. The value in the working state. Therefore, when the transformer is unloaded, the input power of the primary side (or secondary side) can be considered as the core loss of the transformer. ^[5]

When doing a short-circuit test, the low-voltage winding is generally short-circuited, and the test voltage is applied to the high-voltage winding so that in the rated tap position, the primary current reaches the rated value and the secondary current also reaches the rated value. Copper loss at rated load. Because the secondary side of the transformer is short-circuited, the working magnetic flux in the iron core is much smaller than in the rated working state, and the iron loss can be ignored. At this time, the transformer has no output. Therefore, the entire input power of the short-circuit test is basically consumed. In the transformer primary and secondary winding resistance, this is the copper loss of the transformer. ^[5]