Transformer and other electrical machines in per unit system

Express the various quantities of transformer and other electrical machines in per unit system make the analysis easy.

Answer

An important factor in the design and operation of electrical machine is the relation between the life of the insulation and the operating temperature of the machine. Therefore, temperature rise resulting from the losses is a determining factor in the rating of a machine.

We know copper loss in a transformer depends on current and iron loss on voltage, thus the various quantities of a transformer and other electrical machines must be expressed in per unit system to make the analysis easy.