Multiple-inlet air-cooling systems for turbo-alternators are applicable for units rated up to_______________?
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Answer: C. 60 MW
Explanation
Air cooling capacity becomes insufficient to handle thermal losses in turbo-alternators exceeding 60 MW. Multiple-inlet ventilation pathways distribute cooling air efficiently across long stator cores. Air pressure drops become unmanageably high if single-path ventilation is used for larger machines. Turbo-alternators rotate at high speeds and generate concentrated heat within generator cores. Air cooling systems require large volume blowers and extensive external ductwork infrastructure. Hydrogen cooling replaces air in larger generators to handle ratings well beyond 60 MW.
Medium-scale power plants utilize air-cooled turbo-alternators for reliable and economical operation. Proper ventilation design prevents localized hot spots that could damage core insulation papers. Exceeding 60 MW typically requires switching to hydrogen or direct liquid cooling technologies. Ratings of 10 MW or 30 MW are well within the capability of simpler single-inlet systems. Option D at 150 MW far exceeds the practical thermal limits of standard air-cooling technology. Large modern power stations rely exclusively on hydrogen or water cooling for high-capacity units.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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