A typical cases of pinion vibration in parallel shaft turbo gear units

摘要

Speed increasing parallel shaft double helical turbo gear units are commonly used in centrifugal compressors and high energy pump applications. Suchrnturbo-gears are API 613 compliant (Titled as -Special Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services) and have horizontal offsetrntransmission line, with journal bearings on the high speed shaft and low speed shaft. When a full load full speed complete unit test is carried out, pinionrndynamic behaviour is found to be different than what observed during full speed no load condition as mandated in API 613. During this test, gear box highrnspeed pinion may show up with high vibration or combination of both during certain load and speed combination in spite of proper balancing and alignment.rnSince full load full speed test is kept as an option in API 613 , hence these type of vibration may not be detected during a no load test in gear boxrnmanufacturer’s premises. These types of vibration patterns are not explicitly addressed in API 613. The first objective of this paper is to cover analytical,rndesign and diagnostic aspects which can be helpful to mitigate above issues before it is towed out from manufacturer’s premises. The second objective of thernpaper is to suggest installation /innovation / design modification on high speed pinion as a pre-emptive approach which can save time to mitigate ifrnencountered during any certain speed –load combination.