Question 486General Subjects - Assistant Engineer

The correct answer is B) Maximum vibration limits and the change in vibration levels over time. In evaluating the condition of rotating machinery, both the maximum vibration limits and the change in vibration levels over time must be considered. Excessive vibration can indicate developing problems, and monitoring the trend in vibration levels can help identify when machinery may require maintenance or repair. Simply looking at the change in vibration over time, without regard to maximum limits (option C), or only considering the maximum limits without the historical trend (option D), would not provide a comprehensive assessment. Option A is incorrect as it references minimum limits instead of the more critical maximum limits.