Torque vs Horsepower Explained

There is a lot of confusion over Lawnmower Horsepower ratings. Horsepower rated engines are rated at their maximum horsepwer RPM. That is to say that is the maximum HP that the engine can produce and sustain. In the case of Lawnmowers there are safety laws that govern the tip of the blade speed. Most 21" lawnmowers will be governed to run at 3,200rpm. In the past a mower might have a 6hp engine installed but the engine only makes 6hp at say 4,500rpm. In that case the engine governed at 3,200rpm would not be producing its advertised 6hp. Some people have taken the Lawnmower industry to task on this issue lately. Now the engines are rated with Size, either CID or CC designations that speak nothing of power, or are rated with a torque specification relative to the use intended. For a good explanation of torque go to http://www.briggsandstratton.com/display/router.asp?DocID=64103

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