What is all day efficiency of Transformer

The ratio of output in kWh to input in kWh of an electrical transformer over a period of 24 hours is technically termed as all-day efficiency.

Mathematical formula for all day efficiency of transformer is:

η_all-day = kWh output in 24 hours/kWh output in 24 hours

Also see: What is significance of all day efficiency of transformers

Álso see Most Important Questions on Transformers:

1. Why you hear Noise near Transformers
2. What happens if you supply 50 Hz to a 60 Hz transformer
3. What are some advantages of Oil over air as a cooling medium in Power Transformers
4. Why you use Oil in Transformers
5. Dot convention on Electrical Transformers

Further Reading/Handbooks on Transformers:

1. The Ultimate Guide to Transformers
2. The Transformer Polarity Handbook
3. Electrical Transformers Handbook
4. What does 3000:1 indicates on Current Transformer
5. Current Transformer
6. Rating Factor of Current Transformers
7. Transformer’s Power and Current Capacity
8. Instrument Transformer Connections Handbook PDF Download