# The Efficiency of a Transformer will be Maximum when

By Mandeep Kumar|Updated : June 23rd, 2022

The efficiency of a transformer will be maximum when the iron losses (constant losses) become equal to copper losses (variable losses). Generally, the efficiency of transformers vary 95% to 98.5%.

## Answer: The efficiency of a transformer will be maximum when the iron losses (constant losses) become equal to copper losses (variable losses).

The transformer that is designed for maximum efficiency is known as Power Transformer. The efficiency of a transformer can be calculated by using the formula: Efficiency = (input - losses) / input = 1 - (losses / input). Transformer efficiency affects its ageing and performance.

To determine the efficiency of a transformer, Open Circuit Test and Short Circuit Test are used to calculate rated core and winding losses.

Summary:

## The Efficiency of a Transformer will be Maximum when

The efficiency of a transformer will be maximum when the constant losses i.e. iron losses and variable losses i.e. copper losses are equal. Formula to calculate transformer efficiency is (input - losses) / input = 1 - (losses / input).