Extended condensate torque estimation considering the starting time of dryer section of paper machines

The presence of condensate inside the dryer cylinders of paper machines produces an important increase of the required torque and power during the startup. A condensate load over 1% accumulated can produce a drive overload and eventually an overload trip. This paper evaluates the effect of the starting time of the accelerating ramp on the torque and power requirements, and in the transition to the rimming stage, in a 500mm diameter cylinder, both without and with spoiler bars. Three ramp times are evaluated: 60, 120, and 240 seconds, and for each accelerating time the condensate load is varied from 0.5% up to 12%, tabulating the maximum torque and power, and the initial and final speeds of the transition to the rimming stage. Results will permit to extend the ability of a previously developed estimation algorithm to be robust and accurate for different accelerating ramps used in the dryer sections.