Question

The disadvantage of Hopkinson's test on two dc shunt machines is

• A. \( \text{copper and iron losses are assumed equal} \)
• B. \( \text{requires two unidentical machines} \)
• C. \( \text{iron and mechanical losses are assumed equal} \)
• D. \( \text{iron and mechanical losses are assumed unequal} \)

Hint:

Hopkinson's test requires two identical machines, which rules out option (2). Its main drawback lies in assuming that the stray losses (iron + mechanical losses) can be cleanly halved and shared equally between the motor and generator, ignoring the differences in field excitation.

Answer 1

The Correct Option is C