How does a single-start worm gear reduce speed and what is its typical efficiency range?

• A. Speed is reduced by the gear ratio of worm wheel teeth to starts; typical efficiency is about 25-40%.
• B. Speed is reduced by the number of teeth on the worm; efficiency about 60-80%.
• C. Speed is increased by the gear ratio; efficiency about 25-40%.
• D. Speed is independent of gear ratio; efficiency about 90%.

Answer: (A)