An electrical motor has a Service Factor.

The number assigned to a motor indicates how much more work a motor can be expected to provide over and above it’s rated horsepower.

An SF (service factor) of 1.15 means that a 1 HP motor can do work up to 1.15 HP for a period of time.

The motor service factor should not be used in the installation, but rather, is a safety factor to be used when the load temporarily exceeds the nominal rating of that motor. Here’s more information.