How Open Circuit Test is performed on Transformers

Open circuit test is used to find core or iron losses on transformer. The figure below displays the circuit diagram for open circuit test on transformers:

1. Apply the full rated voltage.
2. Since load current is zero, only exciting current results.
3. Since exciting current is small, power loss in the winding resistance is negligible, and the wattmeter reading is only core loss.

Álso see Most Important Questions on Transformers:

1. How Short Circuit Test is Performed on Transformer
2. Why you hear Noise near Transformers
3. What happens if you supply 50 Hz to a 60 Hz transformer
4. What are some advantages of Oil over air as a cooling medium in Power Transformers
5. Why you use Oil in Transformers
6. 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