The loses caused in operation including two parts:
1. It is caused by the iron core. When the coil is energized, the magnetic force lines are alternating, causing eddy current and hysteresis loss in the iron core. This loss is collectively called iron loss.
2. It is caused by the resistance of the coil itself. When current flows through the primary and secondary coils of the transformer, there is a loss of electrical energy. This loss is called copper loss.
The sum of iron loss and copper loss is transformer loss, and these losses are related to transformer capacity, voltage and equipment utilization. Therefore, when choosing a transformer, the capacity of the equipment should be as consistent with the actual usage as possible to improve the equipment utilization rate, and be careful not to make the transformer operate under light load.