How does torque create tension?

Torque is a force at a distance tending to create rotation. Units of torque are force x distance, such as Newton-meters (N-m) or inch-pounds (in-lbs). As you apply torque into a shaft, the force created at a given radius about that shaft is equal to torque divided by radius.

Example 1: Given 100 N-m applied to a 200mm diameter roller (0.1 m radius), the force at the roller’s surface will 100 N-m / 0.1 m = 1000 N.

Example 2: Given 800 in-lbs applied to an 8-in diameter roller (4-in radius), the force at the roller’s surface will be 800 in-lbs / 4-in = 200 lbs

Constant torque applied to a roller will create a constant tension (or tension change).

Tension created from constant torque applied to the center of a winding or unwinding will vary inversely with changing roll diameter, increasing as the unwinding roll diameter goes down and decreasing as a winding roll grows.

torque to tension