Vibration Module Questions A+B and Balancing

Question 1

Vibration analysis refers to;

Answer 1

Detecting, measuring, and analyzing the vibration, determining whether it is within normal machine parameters.

Question 2

Oil condition monitoring allows the technician to;

Answer 2

Analyze contamination in the lubricant.

Question 3

Infrared Thermography allows for the measurement of;

Answer 3

Heat being emitted.

Question 4

True or False;
Frequency can be measured in cpm.

Answer 4

True

Question 5

True or False;
Hertz is a measurement of frequency.

Answer 5

True

Question 6

Amplitude is;
a- how often
b- dominant frequency
c- imbalance
d- how much

Answer 6

D - How much

Question 7

Which reading is used to see how one part is shaking in relation to another part?

Answer 7

Phase

Question 8

What is necessary to cause vibration in a machine or piece of equipment?

Answer 8

Force

Question 9

What is peculiar to imbalance amplitude readings?

Answer 9

Similar in the vertical and horizontal directions.

Question 10

A type of resonance that occurs when a shaft or other rotating component is revolving at a speed which has reached or is close to reaching its natural frequency is known as;

Answer 10

Critical Speed

Question 11

What term identifies the frequency with the largest amount of vibration?

Answer 11

Dominant Frequency

Question 12

What is the purpose of a transducer?

Answer 12

To convert a vibration into an electrical signal.

Question 13

Name 3 types of transducers;

Answer 13

• Displacement
• Velocity
• Accelerometer

Question 14

Describe HVA measurements;

Answer 14

H - Horizontal Position
V - Vertical Position
A - Axial Position

Question 15

Why is it a good idea to take readings when the machine is installed?

Answer 15

Because the initial signatures establish a baseline reference and give you a guide to trends with the machine.

Question 16

Why can you not ignore the small vibrations showing up at each side of the dominant frequency on a graph?

Answer 16

They could be indications of impending bearing troubles.

Question 17

What are the 4 products of oxidation in oil?

Answer 17

• Gum
• Varnish
• Sludge
• Acids

Question 18

When an oil sample is removed from a point in a circulating system, it is called a ____ ____ sample.

Answer 18

LIVE ZONE

Question 19

Do not have oil sample collection points located at _____________ or _____________.

Answer 19

Dead pipe legs or after filters or separators.

Question 20

True or False;
The oil sample bottle is always filled completely full.

Answer 20

False
- You must allow room in the container for agitating the sample at the analysis lab.

Question 21

True or False;
Infrared radiation is visible.

Answer 21

False
- Infrared radiation is visible, but it gives off heat.

Question 22

A thermal imaging camera produces an image called a;

Answer 22

THERMOGRAM

Question 23

Mechanical equipment tends to ____________________ prior to failure.

Answer 23

RISE IN TEMPERATURE

Question 24

Emissivity is the materials ability to;

Answer 24

EMIT THERMAL RADIATION

Question 25

Define imbalance;

Answer 25

Imbalance is the unequal distribution of weight about a centreline.

Question 26

List 4 ways a machine becomes unbalanced;

Answer 26

• Wear
• Buildup
• Cracks
• Fatigue

Question 27

How does imbalance affect vibration?

Answer 27

The greater the amount of imbalance present, the greater the amount of vibration felt.

Question 28

If an imbalance condition is present within a machine, how are the forces from imbalance affected by rotor speed?

Answer 28

The amount of force caused by the lack of balance is proportional to the rpm squared.

Question 29

How does doubling the rotor speed affect the force caused by imbalance?

Answer 29

Doubling the rpm quadruples the force caused by imbalance.

Question 30

When the source of vibration is primarily imbalance, how do the vertical and horizontal phase readings compare?

Answer 30

The vertical and horizontal readings are similar.

Question 31

Why are horizontal and vertical phase readings not exactly equal?

Answer 31

Because the pickup axis is oriented in a different angular position.

Question 32

Imbalance appears at what frequency of vibration?

Answer 32

1x rpm

Question 33

What are 3 other sources of 1x rpm vibration?

Answer 33

• Bent Shaft
• Eccentric armature
• Misaligned shafts
• Imbalance

Question 34

True or False;
To balance, you should be able to observe a reference mark on the shaft.

Answer 34

True
- When balancing you should have a reference mark on the shaft.

Question 35

True or False;
Couple imbalance is created by equal heavy spots at each end of the rotor, but on opposite sides of the centreline.

Answer 35

True
-Couple imbalance is caused when heavy spots are on opposite sides of the centreline.

Question 36

True or False;
With couple imbalance, there is a 180 degree phase difference between rotor ends.

Answer 36

True
- With a couple imbalance there is a 180 degree phase difference between rotor ends.

Question 37

True or False;
When balancing, the reference mark does not change when the trial weight location is changed.

Answer 37

False;
- The reference mark changes if the heavy weight changes.