Case History of a Short Shutdown Drive Upgrade, 1996 Process Control, Electrical & Info. Conference Proceedings
When the time comes where the drive system that has been operating on a paper machine or winder becomes old and difficult to maintain, the user is forced to look for an alternative that will solve the immediate problems and minimize the capital outlay. Rebuilds are typically selected when cost is the major concern because of the lower initial cost. Regardless of whether the system is completely new or a rebuild, the overall equipment package needs to provide the user with a better source for parts, enhanced diagnostics and increased reliability. This “new” drive system does not always mean that everything is new. Budgetary constraints may prevent a complete full scale replacement. It may involve replacing the old drive power structure and controller, while maintaining as many of the motor and power circuit wiring as possible. A major constraint involved with many paper machine drives upgrade projects is the amount of machine downtime necessary for the replacement and tie-in of this new equipment. The downtime demands are a heavy factor in determining the selection of the supplier of the equipment, the type of the technology (AC or DC) and the definition of the scope of the replacement. This paper is one of a series describing various approaches taken to minimize the amount of paper machine downtime needed for upgrading its drive system. The approach utilizes existing DC motors, cabling, drive control enclosures and power feed sources. It also details the new drive equipment, control technologies, tachometer technologies and innovative installation techniques. All of these items are considered necessary to minimize the installation downtime for the paper machine.