A factor, typically from about 1.0 for a smooth electric drive on a uniform load up to 2 or more for crushers, mills and other heavy-shock duty, by which the application power is multiplied before choosing a catalog gear unit. It accounts for shock loads, hours per day and start frequency that the base rating does not include. Choosing too low a service factor is a common root cause of premature reducer failures.
Rock crusher needs a 2.0 service factor on a 50 horse motor, so that 50 horse reducer won't do it, look at the hundred.
A catalog rating assumes a service factor of one; choosing the right factor for the duty is the buyer's job.
Also heard as
- SF
Related terms
Bending stress
The tensile stress in the root fillet of a loaded tooth, which decides whether teeth break off.
Contact stress
The compressive stress where two tooth flanks press together, which governs pitting life.
Box
Shop shorthand for a gearbox, reducer or transmission, as in the box is whining or pull the box.