Question

When DC machine achieves maximum efficiency:

• A. Machine is fully loaded
• B. Variable losses are equal to constant losses
• C. No load losses are equal to full load losses
• D. Machine attains maximum speed

Hint:

Maximum efficiency in DC machines is reached when variable losses equal constant losses.

Answer 1

The Correct Option is B

A DC machine achieves maximum efficiency when the variable losses (such as copper losses) are equal to the constant losses (such as core losses). This balance minimizes total losses and maximizes the efficiency.