Replacement of mechanical PIVs by AC drives off machine coater rebuild -lineshaft to sectional

Abstract

It was in the late '60s that Mead Paper decided to add the No.3 paper machine and off machine coater (OMC) to its mill in Escanaba. The Beloit Corporation designed and built the machines using a lineshaft with a differential mechanical drive system and analog DC helper drives. The paper machine's lineshaft is driven with a classic steam turbine. The off machine coater's lineshaft prime mover is two "in-line" DC motors and respective drives. The drive systems have been up-graded several times over the years, but this paper is about the February 2002, OMC mechanical rebuild that replaced the positive infinitely variable (PIV) units on each of the machines five lineshaft differentials. The result of replacing the weakest link (the PIV) of the mechanical drive with a small horsepower AC motor/drive has increased the speed and control capability of the off machine coater, much to the delight of operators.