Modal Analysis and Engineering Application of an Axially Adjustable Quick-Release Temporary Shaft Vibration Mounting Bracket

A modular, axially adjustable, quick-release shaft vibration mounting bracket is developed to enable temporary shaft vibration monitoring in the journal bearing region of large steam turbine–generator units without pre-installed measurement points. Finite element modal analysis shows that the first natural frequency of the bracket is 213 Hz, well above the 1× rotational frequency of 50 Hz at the rated speed of 3000r/min. Field application results demonstrate stable and continuous vibration signals during the startup run-up process, with no abnormal amplification caused by structural resonance or installation looseness, confirming the applicability of the proposed bracket for shaft vibration monitoring under complex operating conditions without affecting the original structure or oil deflector function.