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When a heavy industrial application requires a planetary gearbox in the 30,000\u2013500,000 Nm torque range, two series typically dominate the shortlist: the S series<\/strong> (replacing Brevini Riduttori S300\u2013S7500) and the 311 series<\/strong> (replacing Bonfiglioli Trasmital 311L \/ 311R). Both are high-torque planetary gear units with overlapping torque ranges and similar applications. Choosing the wrong series adds cost or leads to a unit that cannot be certified for the project’s requirements. This guide compares them across six practical selection criteria \u2014 and identifies the specific conditions under which each series is the correct choice.<\/p>\n<\/div>\n The S series industrial planetary gearbox<\/strong> was originally developed by Brevini Riduttori as a high-density industrial and marine drive solution. Its design philosophy prioritises maximum torque in minimum volume \u2014 achieving 40\u201360% space and weight reduction compared to spiral gearboxes at equivalent torque ratings. The full range covers S300 through S20000 (13 frame sizes), with rated torques from 34,000 Nm to 2,170,000 Nm and DNV type approval as standard.<\/p>\n The 311 series planetary gearbox<\/strong> was developed by Bonfiglioli Trasmital as a modular industrial planetary for a broader range of applications \u2014 covering both inline (L) and right angle (R) configurations within the same housing, with ratio ranges up to 2,200:1 inline and 800:1 right angle. The 311 frame sits at 35,000 Nm rated torque and 180 kW rated power, within the broader 300\u2013321 series range covering 1,000\u20131,100,000 Nm.<\/p>\n Both series sit in the same general torque class for the 311 vs S300\/S400\/S600 comparison. The key differences lie in certification requirements, output configuration flexibility, and application focus.<\/p>\nOverview: The Two Series at a Glance<\/h2>\n
Side-by-Side Specification Comparison<\/h2>\n