Relationships between out of balance and misalignment and their vibration characteristics

• Main Author: Chua, Chee Siang.
• Format: Final Year Project Report
• Language: English; English
• Published: Universiti Malaysia Sarawak (UNIMAS) 2004
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://ir.unimas.my/id/eprint/23244/1/Chua%20Chee%20Siang.pdf; http://ir.unimas.my/id/eprint/23244/4/Chua%20Chee%20Siang%20-%20full.pdf; http://ir.unimas.my/id/eprint/23244/

Majority of the machinery in industries nowadays consists of rotating or moving components. Any fault in this rotary component may lead to adverse vibration and thus the smooth running of the system. However, each type of machinery fault exhibits a characteristic vibration signature which is uniquely its own. The signal is the sum total of the design, manufacture, application, and wear of each of its components. Unbalance normally generates 1x rotating speed (RPM) dominant vibration in vibration spectrum, due to the cyclic excitation force that encounter each time the machine makes a full revolution. On the other hand, 2x RPM dominant vibration will normally presented in vibration spectrum for misalignment problem, where each of the two shaft causing a cyclic excitation forces. Phase relationship between inboard and outboard bearing across coupling, will be the easiest way to differentiate the above 2 mechanical defect, as misalignment normally will also generate high vibration at 1x RPM.