We cannot observe mechanical losses but electrical losses will occur like copper and iron losses. This article discusses an overview of different types of losses in a transformer.
Transformer substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Before being used, electric power may flow through several transformer substations at different voltage levels.
The main difference between the step-up and step-down transformer is that the step-up transformer increases the output voltage, while the step-down transformer reduces the output voltage.