Basic Analysis

Question 1

What is DAT and how do you calculate it?

Answer 1

Data Acquisition Time - Time to acquire data set

Number of Lines (N) Divided by Frequency Span (Fmax)…

Question 2

How do you calculate the Period of a Section?

Answer 2

Counting the number of minor divisions in one cycle. Then multiplying that by the time value of each division.

Question 3

Convert Sec/Cycle to Cycle/Sec

What unit is Cycles/Sec Equivalent to?

Answer 3

F= 1/T

F: Frequency
T: Period

Herts, Hz

Question 4

Convert CPS to CPM

CPM to CPS

Answer 4

Multiply by 60

Divide by 60

Question 5

1X

Answer 5

Frequency =Operating Speed

Question 6

2X

Answer 6

Frequency = 2X Operating Speed

Question 7

Orders

Answer 7

Multiples of Operating Speed

Question 8

Harmonic Vibrations in timewave indicate

Answer 8

One Frequency/Sine Wave

Mass Unbalance related to RPM

Question 9

Distinctive Pulses in timewave indicate

Answer 9

Rolling Element or Broken gear teeth faults

Question 10

When Analyst sets up Analyzer, three decisions have to be made…

Answer 10

1) Fmax: Maximum Frequency
2) Number of Lines
3) Window(Type of Analysis)

Question 11

Random Vibration in Timewave Form indicate

Answer 11

Flow Issues

Question 12

How to Calculate Resolution(Hz):

Question 13

Beats in Time wave indicate

Answer 13

two components of different vibrations are nearby.

Question 14

When a forcing frequency such as operating speed is close to or equal to a natural frequency, the condition of _____________ occurs and the _________ is amplified

Answer 14

Resonance
Vibration

Question 15

The frequency of the rotor that matches the natural frequency of the Machine is called ____________________

Answer 15

Critical Speed

Question 16

Mass Unbalance occurs when the _____________ and the __________ of a rotor do not coincide.

Answer 16

Geometric Center (Shaft Centerline)
Mass Center

Question 17

Mass unbalance is sometimes difficult to distinguish between misalignment in vibration analysis because

Answer 17

They both show up in 1x. A phase analysis would be required to see further because the nature of the forces are different.

Question 18

Looseness can be identified in the spectrum as

It is caused by

Answer 18

Once per revolution vibration plus orders of operating speed.

This is caused by excessive bearing clearances and untightened bolts.

Question 19

Beats occur when…

This produces what in the timewave

Answer 19

two vibration sources have frequencies close to each other or a vibration source close to a natural frequency.

Excessive Amplitudes

Question 20

When a Rolling element passes over a bearing defect in the races or cages, __________________ are generated.

Answer 20

Pulse like forces

Question 21

Rolling element bearings generates ________________ unique to their geometry and ____________

Answer 21

frequencies
operating speed