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Title: Vibration Analysis Certification Exam Preparation Package Certified Vibration Analyst Category I: Fault Analysis and Correction (Part 5)

Series: CAT I PREP I SERIES PRACTICE TESTS FOR CVA (Link)

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Regards- Ali M. Al-Shurafa

Vibration Analysis Certification Fault Analysis

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Please comment on the below practice question (sample) for vibration analysis certification exam. Is this suitable for Level 1, 2 or 3? 6, 18 or 36 months experience, respectively. Or maybe not suitable at all.

The intent of many of the questions in the booklets is to trigger the attention to a possible misunderstanding in a concept or its application. However, based on previous posts and some private messages, the level of difficulty of some practice questions was controversial.

Perhaps, the language clarity also adds another barrier.

Regards- Ali M. Al-Shurafa

 

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From a language view, speed and frequency are mixed in the question.  I tend think of cpm as a frequency and rpm (perhaps frequency or speed) as a type of speed or angular velocity. 

Additionally, I would take Hz as a frequency, not a speed.  50 Hz is the frequency of the line.  Synchronous implies something is related (synchronized) to something else.  Most who are around motors are likely to take this as to the line frequency.

Have a fluid drive that can lock-up, and the story of what is synchronous changes - would be a motor to line frequency or the driver to the driven?

William_C._Foiles posted:

I tend think of cpm as a frequency and rpm (perhaps frequency or speed) as a type of speed or angular velocity. 

Additionally, I would take Hz as a frequency, not a speed.  50 Hz is the frequency of the line.  Synchronous implies something is related (synchronized) to something else.  Most who are around motors are likely to take this as to the line frequency.

I think as all rotational speed is frequency cyles/time, rpm, rpm or Hz.... Apparently people like to think only hz are frequency....

 

 

fburgos posted:
William_C._Foiles posted:

I tend think of cpm as a frequency and rpm (perhaps frequency or speed) as a type of speed or angular velocity. 

Additionally, I would take Hz as a frequency, not a speed.  50 Hz is the frequency of the line.  Synchronous implies something is related (synchronized) to something else.  Most who are around motors are likely to take this as to the line frequency.

I think as all rotational speed is frequency cyles/time, rpm, rpm or Hz.... Apparently people like to think only hz are frequency....

 

 

I agree with Bill on this, frequency is most often Hz or cpm.

”Fburgos”, if you handed me a spectrum and I pointed to some peak and asked what is that frequency, would you replay it is “X” rpm?

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