Ronald Dela Cruz Barro

Condition based maintenance method of rotating machineries generally applies vibration monitoring and analysis technique. The vibration response is an ideal source of information relevant to the machine condition. In addition, real-time vibration measurement and analysis data can provide fault diagnosis and performance of the machine. For the complex propulsion shafting system vibration monitoring, a number of components will be checked simultaneously and this necessitates a reliable and efficient monitoring system. Likewise, continuous monitoring of vibration data will require large storage capacity for the purpose of performance prediction and future investigation. In this paper, a global vibration and ship performance measurement were carried out on a coastal trade 580GT class passenger carferry propulsion shafting system. Correlation between propulsion shafting system parameters such as ship speed, propeller shaft rpm, torque and power were analyzed. Further, the EDiMs (Energy Efficiency Design Index or Operation Index Monitoring System) and EVAMOS (Engine/Rotor Vibration Analysis and Monitoring System) software were utilized to record and analyze all measurement signals including ship position (latitude and longitude) and at the same time have the capability to store large data. Results herein are made as basis for condition diagnostics and performance estimation of the propulsion shafting system.

Torsional Vibration Characteristics of Shaft Generating System Direct-coupled with Low-speed Two Stroke Diesel Engine Low-speed Two Stroke Diesel Engine;Shaft Generating System;Torsional Vibration; Fuel oil consumption cost varies depending on every ship operation and this roughly amounts to 70 % of shipping companies' total revenue. As such, efforts towards improved fuel economy are being pursued. An annual 1 % reduction in fuel consumption is perceived to result in saving tens million US dollars on the global fleet operation. One approach is the application of power take-off configurations which are seen to increase fuel oil economy and are suitable for power generation. In this study, the dynamic properties of a shaft generator coupled on a 10S90ME main engine of an 18 600 TEU container vessel is presented. The vibratory torque and angular velocity variation was examined through theoretical analysis and actual vibration measurement. The result of the study suggests a review on existing classification rules for generator design and the lowering of vibratory torque and angular velocity variation guideline.

The propulsion system which applies diesel engine with reduction gear as prime mover generally installs elastic coupling between engine and intermediate shaft. This coupling can isolate the vibratory torque excited by diesel engine, or excess hydraulic variation of the propeller occurring due to external impact. Hence, diesel engine and the reduction gear can be operated safely by adapting the elastic coupling to the system. In this paper, a case is presented wherein the elastic coupling for a skimmer vessel was repeatedly damaged by unknown vibration origin during sea trial. The authors analyzed the possibilities and causes of the elastic coupling failure thru global vibration measurement and past incident investigation. Applied countermeasures are reviewed and an integrated flexible coupling design is presented.