Question

Which of the following is a constant loss in an electric machine?

• A. Armature copper loss
• B. Field copper loss
• C. Core loss
• D. Load copper loss

Hint:

Constant losses in electrical machines are \[ \boxed{\text{Core loss + Mechanical loss}.} \] Copper losses vary with load current.

Answer 1

The Correct Option is C

Step 1: Classify the losses in an electric machine. Losses are mainly of two types: \[ \begin{aligned} \text{Constant losses} &\rightarrow \text{Core loss, mechanical loss}, \text{Variable losses} &\rightarrow \text{Copper losses}. \end{aligned} \]

Step 2: Identify the constant loss. Core (iron) loss consists of \[ \boxed{\text{Hysteresis loss + Eddy current loss}} \] and is nearly constant at rated voltage. Hence, \[ \boxed{\text{Core loss}} \] is the correct answer. Therefore, \[ \boxed{(C)} \] is the correct answer.