The operating condition required for maximum efficiency in a D.C. generator is______________?
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Answer: D. variable losses = constant losses
Explanation
Maximum efficiency in electrical generators occurs at the precise operating load where variable losses equal constant losses. Variable copper losses fluctuate with the square of the load current drawn by external circuits. Constant iron and mechanical friction losses remain virtually unchanged regardless of the output electrical load. Efficiency is mathematically defined as the ratio of electrical power output to total power input. Constant losses include core hysteresis, eddy currents, windage, and bearing friction losses. Variable losses comprise the resistive heating losses within the armature and field windings.
Power plant engineers design generator ratings so that peak efficiency aligns with typical daily average loading conditions. Balancing loss components optimizes fuel consumption and reduces operating temperatures in continuous generation facilities. Understanding loss equivalence helps technicians evaluate machine performance under varying industrial load profiles. Equating eddy current losses to stray losses does not establish the mathematical condition for peak generator efficiency. Hysteresis and eddy current losses are both components of constant iron losses rather than the variable load losses. Copper losses can never be zero in a practical operating generator carrying functional load currents.
- Subject
- Engineering
- Category
- Electrical Engineering
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- —
- Difficulty
- medium
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