Modeling and Evaluation of Paper Machine Coater Sections

Coaters sections are challenging to tune during the commissioning of a paper machine. This paper presents a detailed mechanical-electrical model of a one-coater section which includes a linear, operating point model of the sheet in the different spans, all the drivetrain components, and the vector controlled ac drives. The sheet model considers tail widening as well as the effect of coating and drying on the sheet elastic constant, activation of the torque current control and the beginning of coating. The developed model allows for complete evaluation of the different transient events including paper slack due to load impacts. Results show that the best performance of the drives is obtained operating the spans with even sheet tensions, which reduces and/or eliminates the operation of the drives in regeneration or braking zones.