Vibration Analysis

Question 1

______________ is the movement of a body about its reference position. For rotating equipment the centerline of the rotating shaft is the reference.

Answer 1

Vibration

Question 2

imbalance in the fan could be caused by wear or build up on the blades. looseness could be present within the machine. The effects of the fluidized air stream passing the blades as the blades pass the dischange ducting could cause a vibration. A bad bearing ing the motor or final drive shaft could be vibrating. this is an example of

Answer 2

vibration

Question 3

a ________ is a graphical depiction of vibration

Answer 3

signature

Question 4

temperature analysis is also known as ?

Answer 4

infrared thermography (IRT)

Question 5

____________ requires no physical contact with any device to the equipment therefore, the system may be monitored without disrupting normal operations.

Answer 5

Temperation analysis

Question 6

the scale of emissivity ranges from?

Answer 6

0.00 (where there is no emission) to 1.00 (where the object is completely emitting energy)

Question 7

________ measures the heat beingemitted and allows comparison with a bae-line. Increassed temperatures indicate a fault that could precede failure.

Answer 7

Infrared thermography

Question 8

_______ is a symptom of a machine that can lead to machine damage or failure.

Answer 8

Vibration

Question 9

_________ refers to detecting, measuring and analysis the vibration and determining whether it is within normal machine parameters.

Answer 9

Vibration analysis

Question 10

Because all mateerails have different characteristics, each displays a different signature when reacting to a forcing frequency. By changing either the mass or the stiffness of an object, you change the vibratory signature of the object. this stand for _________?

Answer 10

machine characteristics/material characteristics

Question 11

_______ is how often an event happens in a unit of time or in one cycle.

Answer 11

Frequency

Question 12

what are 3 terms used to describe vibration?

Answer 12

Frequency
amplitude
phase

Question 13

the _________ is the lowest or first frequency normally associated with a particular problem.

Answer 13

Fundamental Frequency

Question 14

a misaligned coupling can generate _____________orders. which would be a example of fundamental frequency?

Answer 14

1x, 2x or even 3x rpm

Question 15

_______ indicates how much a machine is vibrating.

Answer 15

Amplitude

Question 16

This total distance travelled is called the __________ and may be measured in either imperial or metric

Answer 16

peak-to-peak displacement

Question 17

_______ readings are most consistent between 600 cpm and 60,000 cpm

Answer 17

Velocity

Question 18

the _______ is used above 60 thousand

Answer 18

G’s force (Acceleration)

Question 19

The breakdown of lubrication and resultant surface failure of a bearing is an example of ________

Answer 19

acceleration damage

Question 20

the relationship between displacement, velocity and acceleration is referred to as _______

Answer 20

phase

Question 21

when taking phase readings, keep the _______

Answer 21

accelerometers facing the same direction

Question 22

___________ is the frequency at which an object or system naturally vibrates when a forcing function has been introduced.

Answer 22

natural frequency

Question 23

at ___________ the system amplifies the energy from the forcing function frequency causing large amplitude.

Answer 23

Resonant frequency

Question 24

__________ occurs in any system if the forcing function frequencies are not kept at least 20% outside the natural frequency’s range.

Answer 24

Resonance

Question 25

the _______ of a shaft or rotor occurs when the rotor rotates at or near its natural frequency

Answer 25

critical speed

Question 26

machines should not be operated at or near the ________ of the shaft or rotor: they should operate 20% to 30% outside of a rotor's ______.

Answer 26

Critical speed

Question 27

if a shaft has a natural frequency of 2300 cpm, the shaft is in _______ (shake violently) when the shaft is rotated at 2300 rpm

Answer 27

resonance

Question 28

_________ are developed by the international organization for standardization (ISO)

Answer 28

Severity standards

Question 29

_____ are multiples of the operating speed. For example how often the event occurs with each revolution.

Answer 29

Orders

Question 30

If the period for one cycle is 1 second, then the frequency in cycles per minute = 60 cpm. Frequency can also be measured in ______?

Answer 30

orders

Question 31

what is the rate of change of displacement and is measured as the maximum _____ the vibrating part achieves.

Answer 31

Velocity

Question 32

when placed on a sine wave, the maximum velocity takesplace on ______

Answer 32

the neutral axis

Question 33

________ is the rate of change in velocity and is measured in g's force.

Answer 33

Acceleration

Question 34

at _______, the system amplifies the energy from the forcing frequency causing large amplitude.

Answer 34

Resonant frequency

Question 35

Resonance occurs in any system if the function frequencies are not kept at least _____ outside the natural freqency

Answer 35

20%

Question 36

______ is the time required to complete one cycle of a periodic signal

Answer 36

period

Question 37

__________ are frequencies that are not whole multiples of the rotating speed of the machine.

Answer 37

Non-synchronous Vibration

Question 38

A ________ is normal standard for the vibration of a particular machine

Answer 38

Baseline

Question 39

the process of vibration analysis involves converting a vibration into an electrical signal with the use of transducers, this is ______?

Answer 39

measuring vibration

Question 40

Non-contact eddy current ______________ measure the relative distance between a bearing housing and a bearing journal

Answer 40

displacement transducers

Question 41

_________ are used for gerenal vibration measurement and balancing

Answer 41

velocity transducers

Question 42

A velocity transducer is primarily used to measure velocity, but the analyzer can differentiate or integrate the signal making it capable of measuring _______ and _________ through the machine.

Answer 42

displacement and acceleration

Question 43

___________ are the most common transducers used with vibration analysis equipment. this generate their own power, but often use an amplifier to increase signal strength.

Answer 43

Acceleration transduceers (accelerometers)

Question 44

For repeat readings, use the same method of _____________ each tim. Follow the recommendations the manufacturer suggests.

Answer 44

Mounting transducers

Question 45

A ________ is permanently installed in the machine bearing housing so it can accurately monitor the absolute shaft vibration

Answer 45

shaft rider accessory

Question 46

the transducer is only capable of picking up a vibration that is in line with the transducer. The transducer does not pick up vibrations that are 90 degree to the transducer this is?

Answer 46

pickup mounting positions

Question 47

you must collect information from several directions and at several points on the machine before you can perform any analysis. These positions are usually in the horizontal, vertical and axial (HVA) positions at each bearing location and are commonly referred to as _______

Answer 47

HVA measurements

Question 48

__________ means that the vibration analyzer changes the signal received at the vibration pickup from amplitude versus time to amplitude versus frequency.

Answer 48

Fast Fourier Transform (FFT)

Question 49

When a vibration is complex, sophisticated vibration analyzers are used to _________ so that each can be measured and inspected independently.

Answer 49

separate frequencies

Question 50

Another common use of _________ is to measure the phase angle of the vibration when balancing rotating parts

Answer 50

Strobe lights

Question 51

most basic analysis procedures follow two overall steps which are ___________ and ___________

Answer 51

data acquisition and data interpretation

Question 52

the probe must be located a specific distance from the shaft. The gap setting can be approximately ______ to ______ and is set by the manufacturer's specifications

Answer 52

0.020 to 0.060

Question 53

____________ does not only involve taking vibration readings, but starts with a basic investigation of the machine and its surrounding.

Answer 53

data acquisition

Question 54

once a machine is taken out of service for a complete overhaul or a new machine is installed, you should take new ________

Answer 54

baseline readings

Question 55

This frequency spectrum, a plot of vibration amplitude against frequency is known as the _______

Answer 55

vibration signature

Question 56

_______ is one of the most common cause of vibration

Answer 56

imbalance

Question 57

imbalance can be identified by a vibration frequency that is ________

Answer 57

1x rpm

Question 58

Most of the vibration from imbalance is in the ___________

Answer 58

Radial direction

Question 59

Frequency is usually 1x rpm, but if the ____________is severe there can be frequencies at 2 or 3x rpm

Answer 59

Misalignment

Question 60

The axial vibration component is usually high (about 1/2 or more of the radial amplitude) which is caused by _______________

Answer 60

angular misalignment

Question 61

an axial vibration reading of 50% or more of the radial is a good indicator of __________

Answer 61

misalignment

Question 62

____________ cause vibration problems under several conditions. If the bearing clearance are to loose, the shaft can move around and pound on the bearing

Answer 62

Friction bearing

Question 63

________ usually occurs at frequencies of about 45% to 50% of the shaft rotation.

Answer 63

oil whirl

Question 64

the horizontal/radial position is probably the most commonly used for ___________

Answer 64

transducer measurements

Question 65

_________ which can show ecactvibration waveforms, to identifying certain distinct vibration problems

Answer 65

oscilloscopes