The document discusses the efficiency of transformers. It notes that transformer efficiency is measured as the ratio of output to input power. Losses include copper and iron losses, with iron losses dependent on load. For distribution transformers with varying daily loads, all-day efficiency is measured, which accounts for the transformer's capability over the full day and is always lower than commercial efficiency measured at a single time.

1. Of Bangladesh

2. Efficiency of a transformer

4. Condition for Maximum Efficiency

6. All day efficiency
• The commercial Efficiency of a transformer is given by the ratio
of output power to input power
• The losses in the transformer can be classified into copper losses and
iron losses. The copper losses (hysteresis and Eddy Current Losses)
are independent of the load. The iron losses though are dependent on
the load.
•
In the case of the distribution transformers, the load is continually
varying. It is low in the day time and high in the evenings and night.
Therefore, efficiency measured at any one point of the day would not
be an accurate reflection of the transformer's capability.

7. • Hence, We have the all day efficiency measurement of the
distribution transformers. The formula for the all day efficiency of
the distribution transformers is
• The All day Efficiency is always lesser than the commercial
efficiency of the transformer.