How much torque is needed?

When you hook up a motor to a roller or winder, there are several demands for torque. Add these all up to get the motor torque requirement.

  1. Web torque = Tension x radius (for adhesive webs, the tension must be greater than the adhesion peel force)
  2. Inertial torque = I (moment of inertia) x accelerations (or deceleration)
  3. External load torque = for nipping roller, the nip load will increase the drag in the system, sometimes estimated as tensioning equal to 10% of the nip force.
  4. System torque losses = frictional losses and efficiency losses