Monitoring of winding overhang vibrations on large synchronous motors

Electric large drives have advantages in operating liquid natural gas plants LNG, as they can be operated very flexibly and provide a zero CO2 footprint. Being a rather new application, the reliability of the drive is looked upon critically. Particularly the vibration behavior of the stator winding overhang has attracted attention. Any anomaly in vibration amplitudes needs to be monitored to prevent potential damage of the drive. In order to collect information based on operational measurement data a customized data acquisition system was installed on selected variable speed motors which are fed by frequency-converters at an E-LNG (Electrical) plant. This paper will present the experience collected during a project in which a monitoring system for Condition Based Maintenance (CBM) of VSDS has been installed at an E-LNG plant and operated for about 2 years. The objective for the E-LNG operator is to gain reliability of the VSDS technology and life cycle considerations through this new monitoring technology. In this paper all relevant aspects of installing and operating a condition monitoring system will be presented: • Selection of suitable measurement technology • Purpose of monitoring activities • Potential damaging mechanisms • Influence of developing damage in the vibration pattern • Definition of measurement setup • Concept for data acquisition, storage and general evaluation • Concept for predictive life time analysis • Verification of FEA calculations using measured data • Development of design tools • Operational aspects, fiber optic vibration monitoring as a tool for Condition Based Maintenance • Experience over a two years period of operation will be reported.