Design of foundations for large refiner motors

This paper will discuss the design approach and analysis procedures used in the design of foundations for large refiner motors. To establish the dynamic characteristics of the motors and develop reliable models for the assessment of vibration response, it is necessary to consider the machine/foundation system as an integral unit. The complete system model includes refiner, motor, speed-increaser, foundation and soil parameters. From this study it was determined that stiffening the existing foundation was essential to ensure a satisfactory response of the system under operating conditions. The study also showed that modifications to the motor bearing supports and stator frame stiffening were necessary to avoid high vibration levels at operating speeds. A close working relationship between the foundation designer and the motor designer is essential for the successful implementation of this design approach. Details of the type of communication necessary in such an endeavor are discussed.