A different approach to a paper machine retrofit

Digital control of drive equipment has provided unique opportunities to utilize silicon-controlled rectifier DC-drive systems. It is shown that an economical, functional, and reliable system can be obtained by selecting new modern digital components and logic controls to upgrade an operating drive section. The authors describe the selection process, changes that took place in the design of a system, retrofitting of the new equipment to reusable machine drives, and the installation. The machine start-up and the operation of the equipment after the changeover have provided verification that combining existing DC section electric drives with new digital controllers can be an economic alternative. >