Full definition
Enclosed gear mechanism (gearbox) that reduces input rotational speed while proportionally increasing output torque, per the law of conservation of energy (minus losses). Main types: worm (compact, 5:1-100:1, 45-90% efficiency, self-locking above ~50:1), helical (parallel or right-angle, 3:1-25:1 per stage, 95-98% efficiency), planetary/epicyclic (inline, 3:1-10:1 per stage, 95-97%, very compact), and cycloidal (shock-resistant, 6:1-119:1, 85-95%). Selection based on power, ratio, duty cycle, mounting, and output torque. Per AGMA 6013 and ISO 6336. Standard frame sizes per center distance. Lubrication: mineral or synthetic oil, splash or forced. Brands: SEW-Eurodrive, Nord, Flender (Siemens), Bonfiglioli, Sumitomo, Dodge (ABB). Service factor applies to reducer rated torque.