The correct answer is: C. all-day efficiency
Sumpner’s test is a method of determining the all-day efficiency of a transformer. It is conducted by measuring the transformer’s losses under load and then calculating the efficiency using the following formula:
Efficiency = (Output power – Input power) / Input power
The output power is the power that is delivered to the load, and the input power is the power that is supplied to the transformer. The losses are the difference between the output power and the input power.
Sumpner’s test is a valuable tool for determining the efficiency of a transformer. It can be used to compare the efficiency of different transformers, and it can also be used to track the efficiency of a transformer over time.
The other options are incorrect because they are not the purpose of Sumpner’s test.
- Option A: Temperature is not the purpose of Sumpner’s test. The temperature of a transformer can be measured using other methods, such as a thermocouple or a resistance thermometer.
- Option B: Stray losses are not the purpose of Sumpner’s test. Stray losses are a type of loss that occurs in transformers due to magnetic flux leakage. They can be measured using a variety of methods, such as the open-circuit test or the short-circuit test.
- Option D: None of the above is the correct answer.