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Bretts Millwright Lovechild > Machine Condition Monitoring > Flashcards

Machine Condition Monitoring Flashcards

1
Q

What does amplitude indicate?

A

Amplitude indicates how much a machine is vibrating.

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2
Q

What is displacement?

A

Displacement is the total distance a vibrating part moves either side of its neutral axis.

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3
Q

What is velocity in the context of vibration?

A

Velocity is the rate of change of displacement for a given time.

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4
Q

What is acceleration in the context of vibration?

A

Acceleration is the rate of change in velocity for a given time.

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5
Q

What is the relationship between amplitude measurements?

A

The relationship between these measurements allows you to interpret and calculate vibration characteristics.

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6
Q

How is displacement represented graphically?

A

If a graph is made of the displacement versus time, the graph looks like a sine wave.

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7
Q

What is peak-to-peak displacement?

A

Peak-to-peak displacement is the total distance travelled from one extreme of the motion to the other.

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8
Q

What are the units for measuring displacement?

A

Displacement may be measured in either imperial (mils pk to pk) or metric (microns pk to pk).

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9
Q

In what units is displacement measured?

A

Imperial-1 mil = 0.001 inch.
Metric-1 micron= 0.001mm

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10
Q

When is displacement most often used?

A

Displacement is most often used below 600 pm or 1000 rpm where stress conditions such as flexing and bending are suspected and in balancing procedures.

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11
Q

What is velocity?

A

The rate of change of displacement, measured as the maximum velocity the vibrating part achieves.

Velocity combines displacement and frequency.

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12
Q

How is maximum velocity represented on a sine wave?

A

It takes place on the neutral axis.

This refers to the point where the vibrating part crosses the zero axis.

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13
Q

What is the relationship between velocity and displacement?

A

Velocity combines displacement (how far it moves) and frequency (how often).

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14
Q

How does the velocity of the vibrating part change during motion?

A

It changes from zero at one extreme to maximum in the middle, then back to zero at the other extreme.

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15
Q

What is the standard unit for measuring velocity in imperial systems?

A

Inches per second (in/see or ips).

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16
Q

What is the standard unit for measuring velocity in metric systems?

A

Millimeters per second (mm/s).

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17
Q

Why are velocity readings important for machine condition assessment?

A

They are the best indicator of overall machine condition because the force due to velocity can be large, even if displacement is not severe.

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18
Q

What is the range of consistent velocity readings?

A

Between 600 cpm and 60,000 cpm (60k).

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19
Q

Fill in the blank: The maximum velocity is always used for _______ measurements.

A

[velocity]

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20
Q

True or False: The maximum velocity occurs at both extremes of the vibrating part’s motion.

A

False

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21
Q

What does the frequency of vibration indicate in a machine?

A

It indicates whether the forcing frequency is periodic or random and can help identify specific problems like imbalance or misalignment in the machine.

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22
Q

What is the predominant or fundamental frequency in vibration analysis?

A

It is the frequency with the highest spike on a vibration signature and is usually the lowest or first frequency associated with a particular problem.

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23
Q

If a machine rotates at 1800 RPM, what is the dominant vibration frequency?

A

The dominant vibration frequency matches the machine’s running speed, which would be 1800 cycles per minute (CPM) or 1× RPM.

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24
Q

What are some possible sources of vibration in a machine?

A

Misalignment, imbalance, bearing damage, gear problems, cracked welds, resonance.

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25
Q

What is displacement in the context of vibration?

A

It is the total distance traveled by a vibrating object from one extreme of motion to the other, usually measured in peak-to-peak (pk to pk).

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26
Q

What are the units used to measure displacement in imperial and metric systems?

A

Imperial: 1 mil = 0.001 inch; Metric: 1 micron = 0.001 mm.

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27
Q

When is displacement most commonly used for analysis?

A

It is used below 600 CPM or 1000 RPM when stress conditions like flexing and bending are suspected.

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28
Q

Why is oil condition monitoring important in machine maintenance?

A

It helps avoid costly machine failures and downtime by detecting contamination and potential problems in the lubricant.

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29
Q

What contaminants can affect lubricating oils?

A

Water, varnish, oxidation products, dirt, anti-freeze.

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30
Q

What are the benefits of oil condition monitoring?

A

Planned maintenance schedules, identifying problems before failure occurs, maximizing component life, trending equipment condition, establishing maintenance guidelines.

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31
Q

Which systems are commonly monitored for oil condition?

A

Hydraulic systems, engines, compressors, turbines, gearboxes.

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32
Q

What does temperature analysis help detect in machinery?

A

It detects overloaded electrical circuits, loose connections, and frictional heating of bearings.

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33
Q

What is the range of emissivity used in infrared thermography?

A

It ranges from 0.00 (no emission) to 1.00 (complete emission).

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34
Q

How does infrared thermography help in condition monitoring?

A

It measures heat emitted from objects and compares it with a baseline. Increased temperatures indicate potential faults like mechanical failure.

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35
Q

What type of device is used in infrared thermography?

A

A non-contact radiant energy detector, such as an infrared thermometer.

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36
Q

What information must be identified during vibration analysis?

A

Date of data collection, type of machine, equipment number, machine location, machine speed, bearing type and location, coupling type and location, components within the machine system.

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37
Q

Why is early detection of vibration issues important?

A

It allows for corrections to be made, avoiding machine destruction and reducing downtime.

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38
Q

What maintenance program uses both oil condition monitoring and temperature analysis?

A

Preventative maintenance programs.

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39
Q

What is a harmonic in vibration analysis?

A

A harmonic is a multiple or sub-multiple of the fundamental frequency.

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40
Q

What are the three types of vibrations?

A

Synchronous, non-synchronous, and sub-synchronous vibrations

  • Synchronous vibrations: Frequencies that are whole multiples of the machine’s rotating speed (e.g., 1× RPM, 2× RPM)
  • Non-synchronous vibrations: Frequencies that are not whole multiples of the rotating speed
  • Sub-synchronous vibrations: Frequencies that occur at less than the rotating speed of the machine
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41
Q

What is a baseline in vibration analysis?

A

A baseline is a reference standard for the vibration of a machine, recorded under normal or new conditions.

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42
Q

What does acceleration measure in vibration analysis?

A

Acceleration measures the rate of change in velocity and is expressed in g’s force.

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43
Q

What is the significance of acceleration in high-frequency vibrations?

A

At high frequencies (above 60,000 CPM), the force indicated by acceleration is large enough to cause damage, even if displacement and velocity do not show significant vibration.

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44
Q

What is phase in vibration analysis?

A

Phase is the relationship between displacement, velocity, and acceleration, expressed in degrees.

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45
Q

What does it mean for two points to be ‘in phase’?

A

Two points vibrate in the same direction on the shaft at the same time.

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46
Q

What does it mean for two points to be ‘out of phase’?

A

Two points vibrate in opposite directions (e.g., 180° apart).

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47
Q

What is natural frequency?

A

It is the frequency at which an object naturally vibrates when a forcing function is introduced.

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48
Q

What is resonant frequency, and why is it important?

A

Resonant frequency amplifies energy from a forcing function, causing large amplitude vibrations that can destroy machines.

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49
Q

What is critical speed?

A

Critical speed occurs when a rotor or shaft rotates at or near its natural frequency, causing resonance and a marked increase in vibration.

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50
Q

Why should machines avoid operating at critical speed?

A

Operating at critical speed can damage the machine.

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51
Q

What is the period of vibration?

A

The period is the time required to complete one cycle of a periodic signal.

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52
Q

What is the primary function of a transducer in vibration analysis?

A

To convert vibration motion into an electrical signal.

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53
Q

Which of the following is NOT a type of transducer used in vibration analysis?

A

Pressure transducer.

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54
Q

Why can no single transducer measure all vibration parameters across all frequency ranges?

A

Each transducer type has a different degree of sensitivity and is optimized for specific frequency ranges.

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55
Q

What is the purpose of a severity chart in vibration analysis?

A

To classify vibration levels as smooth, rough, or very rough.

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56
Q

What does the Fast Fourier Transform (FFT) capability in a vibration analyzer do?

A

Changes signals from amplitude vs. time to amplitude vs. frequency.

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57
Q

What is the purpose of a vibration pencil in machine diagnostics?

A

To provide quick measurements of specific vibration characteristics.

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58
Q

What is the primary feature of a portable vibration meter?

A

It is lightweight and capable of taking overall vibration readings.

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59
Q

What is the advantage of a vibration monitor compared to a portable vibration meter?

A

Vibration monitors provide continuous monitoring of vibrations.

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60
Q

How are vibration analyzers different from vibration monitors?

A

Vibration analyzers are more complex and can perform advanced analyses.

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61
Q

What is the primary purpose of a velocity transducer?

A

Velocity transducers are used for general vibration measurements and balancing. They generate their own power and produce voltage proportional to the velocity of motion.

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62
Q

How does a velocity transducer work?

A

A permanent magnet moves relative to a wire coil within the transducer, generating voltage. The faster the motion of the vibration, the larger the voltage produced.

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63
Q

Why are velocity transducers not reliable at very low or very high frequencies?

A

They are not reliable at very low frequencies for displacement and are not accurate at higher frequencies when measuring acceleration.

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64
Q

What do non-contact eddy current displacement transducers measure?

A

They measure the relative distance between a bearing housing and a bearing journal, providing a real-time picture of shaft movement.

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65
Q

What is critical when installing a proximity probe?

A

The probe must be calibrated any time a component is changed, and factors such as shaft run-out, scratches, and variations in the target material can affect its performance.

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66
Q

Why must the shaft be a conductor for eddy current displacement transducers to work?

A

Eddy currents are generated by the conducting material of the shaft, which are necessary for the transducer to measure changes in voltage.

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67
Q

What material is commonly used in accelerometers, and why?

A

Piezoelectric materials, such as quartz or ceramics, are used because they create electrical current when strained by force.

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68
Q

What makes accelerometers especially useful in vibration analysis?

A

They are sensitive to vibrations at very high frequencies and can transform signals into displacement or velocity for analysis.

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69
Q

Why is mounting critical for accelerometers?

A

Any looseness in the transducer mounting can result in incorrect readings, as accelerometers are highly sensitive.

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70
Q

Which transducer is best for measuring displacement, velocity, and acceleration?

A

Displacement is best measured with a displacement transducer, velocity with a velocity transducer, and acceleration with an accelerometer.

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71
Q

Why are accelerometers often used for portable applications?

A

They can measure all vibration parameters and translate vibration signals into all chosen parameters with high accuracy.

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72
Q

Why is the method of mounting a transducer important?

A

Improper mounting can distort the true vibrations, leading to inaccurate readings. Consistency in mounting methods is essential for repeatable results.

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73
Q

What are some common mounting methods for transducers?

A

Common methods include:
* stud mounting (best)
* magnetic pickup (good)
* probe (fair)
* shaft rider accessory (fair)

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74
Q

What are the two ways a strobe light can be used in vibration analysis?

A

• Manually, by adjusting the frequency to match the speed of the rotating shaft for analysis.
• Automatically, by setting it to flash at the dominant frequency of the vibration.

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75
Q

What is the purpose of a transducer-triggered strobe light?

A

It helps identify which components are producing the vibration signal and determines the relationship of the components excited by the vibration.

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76
Q

How is a strobe light used to balance rotating parts?

A

It measures the phase angle of the vibration during balancing.

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77
Q

What is the function of a shaft rider in vibration analysis?

A

A shaft rider monitors absolute shaft vibration by rubbing on the shaft surface and producing readings proportional to the shaft’s movement.

78
Q

Where is a shaft rider installed, and why is this important?

A

It is installed in the machine bearing housing, allowing for accurate and continuous monitoring of machinery that must be consistently tracked.

79
Q

Why is the direction or position of the transducer important?

A

The transducer can only pick up vibrations that are in line with it and does not detect vibrations at 90° to its position.

80
Q

What are HVA measurements, and why are they significant?

A

HVA (Horizontal, Vertical, Axial) measurements are taken at various bearing locations to collect comprehensive data on machine vibrations for accurate analysis.

81
Q

What obstacles might prevent taking vibration readings from all positions?

A

Obstacles like guards, safety issues, or other physical barriers might limit the ability to take readings from all positions.

82
Q

What measurements are compared in vibration analysis to pinpoint machinery problems?

A

Amplitude, frequency, and phase are compared to identify the source and nature of the vibration.

83
Q

What is a common use of a strobe light when analyzing machinery?

A

To make the vibrating object appear to stand still, allowing for detailed inspection and phase angle measurement.

84
Q

What are the two overall steps involved in vibration analysis?

A

• Data acquisition
• Data interpretation

85
Q

List the steps involved in the data acquisition process.

A
  1. Identify the nature of the problem.
  2. Gather information about the vibrating system.
  3. Make a sketch of the machine, with support data.
  4. Take vibration readings.
86
Q

What does the data interpretation process involve?

A

• Analyze vibration data.
• Make corrective recommendations.

87
Q

How do you differentiate between vibration and shock?

A

• Vibration is a continuous condition.
• Shock is a disturbance caused by a sudden applied force, with oscillations that die out before the next impulse.

88
Q

What are some common causes of noise that are not associated with vibration?

A

• Process issues, such as airflow in air ducts.

89
Q

What kind of information should be recorded during vibration analysis?

A

• Shaft diameters and lengths.
• Rotor dimensions and weights.
• Characteristics of the machine (e.g., belts, chains, gears).
• Conditions under which analysis was performed (speed, load, temperature).
• Date and equipment used for analysis.

90
Q

Why is it important to take readings from the same location during a vibration survey?

A

To ensure consistency and accurate comparison of data collected over time.

91
Q

Why is creating a sketch of the machine important in vibration analysis?

A

• It helps determine the best data collection points.
• It aids in identifying potential sources of vibration.
• It ensures order in information gathering.

92
Q

What details should be included in the machine sketch?

A

• Block diagram of all major components.
• RPM of shafts, horsepower, and type of driver.
• Bearing positions, types, and numbers.
• A labeling system for pickup points.

93
Q

Why is it important to talk to the machine’s operator during vibration analysis?

A

Operators often know the normal characteristics and severity of the machine’s vibration and can provide valuable information about when and how the problem developed.

94
Q

What kind of information can an operator provide about a vibration problem?

A

• When the vibration developed.
• Whether it developed suddenly or gradually.
• Conditions under which the vibration occurs.
• Any new or unusual noises during operation.

95
Q

How can imbalance be identified in a vibration analysis?

A

By a vibration frequency at 1× RPM, with the largest amplitude in the radial direction, and amplitude increasing with shaft speed

Overhung rotors may show high axial readings.

96
Q

What happens to the phase of the exciting force if imbalance is causing the vibration?

A

The phase remains stable.

97
Q

How does the amplitude variation help determine if imbalance is the cause?

A

Large variations in amplitude between horizontal and vertical readings indicate that imbalance is likely not the problem.

98
Q

What are the typical frequencies associated with shaft misalignment?

A

Usually 1× RPM; severe misalignment can cause frequencies at 2× or 3× RPM.

99
Q

How does angular misalignment affect vibration components?

A

It results in high axial vibration, usually about half or more of the radial amplitude.

100
Q

What indicates misalignment in axial vibration readings?

A

An axial vibration reading of 50% or more of the radial vibration is a strong indicator of misalignment.

101
Q

How can phase readings indicate misalignment?

A

Erratic phase readings between horizontal and vertical measurements at opposite rotor ends suggest misalignment.

102
Q

What causes component eccentricity, and how does it affect vibration frequency?

A

Caused by machining, installation, or wear that creates off-center parts, resulting in a vibration frequency of 1× RPM.

103
Q

How can eccentricity problems be resolved?

A

By balancing or replacing the defective part.

104
Q

How is gear vibration frequency calculated?

A

It is a multiple of the number of teeth on the gear multiplied by the gear’s RPM.

105
Q

What are common causes of gear problems in vibration analysis?

A
  • Eccentricity
  • Worn or broken gear teeth
  • Oil contamination
106
Q

What kind of readings are typically seen near shafts and gear teeth in cases of gear problems?

A

Sharp, pulse-type readings at frequencies near shaft and gear tooth multiples.

107
Q

What causes stator eccentricity in electric motors?

A

Unequal magnetic forces acting on the stator and rotor, creating radial vibration frequencies at 1× RPM and 2× RPM.

108
Q

How can you determine if the problem is electrical or mechanical?

A

Turn off the power to the motor. An immediate drop in amplitude indicates an electrical problem.

109
Q

What are common causes of mechanical looseness?

A

• Loose bolts on motors, pumps, bearing caps, or pillow blocks.
• A soft foot or loose bolts on a component under high vibration.
• Oscillating forces due to imbalance or misalignment.
• Cracks in the structure.

Mechanical looseness can lead to increased wear and potential failure of machine components.

110
Q

What vibration frequencies are associated with mechanical looseness?

A

• Dominant vibration at 2× RPM.
• Additional frequencies such as ½× RPM and 4× RPM.

These frequencies can help diagnose mechanical looseness issues in machinery.

111
Q

What indicates mechanical looseness in adjacent parts of a machine?

A

If adjacent parts show different amplitude and phase readings, relative motion between the parts could be the cause.

This can lead to uneven wear and potential failure.

112
Q

What are the typical vibration frequencies associated with belt drives?

A

Multiples of the machine speed, such as 1×, 2×, 3×, or 4× RPM of the belts.

Monitoring these frequencies is crucial for diagnosing belt drive issues.

113
Q

What are common causes of belt vibration?

A

• Loose, misaligned, or worn belts.
• Mounting belts on eccentric sheaves.
• Radical torque variations causing belts to stretch and bounce.

Addressing these issues can enhance the performance and lifespan of belt drives.

114
Q

What are solutions to belt vibration problems?

A

• Check and realign sheaves.
• Replace worn belts and ensure proper tension.
• Use belts of the same tension if multiple belts are used.

Proper maintenance can prevent excessive vibration and potential damage.

115
Q

Why are bearing problems difficult to detect in their early stages?

A

The frequencies for bearing problems are very high and produce sharp, high-frequency impulses rather than sinusoidal vibration signatures.

Early detection is critical to prevent catastrophic failure.

116
Q

What is the formula for calculating ball pass frequency for the inner and outer race?

A

• Inner race: 0.60 × n × RPM
• Outer race: 0.40 × n × RPM
(Where n is the number of rolling elements.)

These calculations are important for diagnosing bearing conditions.

117
Q

Why is bearing vibration frequency not an exact multiple of the shaft RPM?

A

Because it depends on the ball pass frequency of the inner or outer race, which is influenced by the ball diameter and pitch diameter.

This relationship complicates the analysis of bearing health.

118
Q

What causes oil whirl in friction bearings?

A

• Incorrect viscosity of oil (too high or too low).
• Excess clearance or improper lubrication.

Oil whirl can lead to increased wear and overheating in friction bearings.

119
Q

At what frequency does oil whirl usually occur?

A

Oil whirl occurs at about 45–50% of the shaft rotation frequency.

Recognizing this frequency can help in diagnosing lubrication issues.

120
Q

What does a bent shaft vibration look like, and what frequencies are associated with it?

A

A bent shaft may mimic a misalignment or imbalance problem.

Vibration frequencies are very high in both the axial and radial directions, often at 1× RPM or 2× RPM.

121
Q

How can you confirm if a shaft is bent?

A

Use a dial indicator at various points along the shaft to check for runout.

This method allows for precise measurement of any deviations in the shaft’s straightness.

122
Q

What causes vibration in blades and vanes, and at what frequency does it occur?

A

Blade and vane problems occur at higher fundamental vibration frequencies that correspond to the number of blades or vanes passing.

The frequency is equal to the number of blades times the rotational speed of the shaft.

123
Q

What happens if a blade is missing?

A

A missing blade results in an imbalance situation, which vibrates at 1× RPM.

This imbalance can lead to increased wear and potential damage to the machinery.

124
Q

What is rubbing in vibration analysis?

A

Rubbing is unwanted friction between two machine parts, often seen in high-speed machinery like steam turbines or axial compressors.

It causes serious vibrations due to rotor or impeller deflection.

125
Q

At what frequencies does rubbing typically occur?

A

Rubbing vibrates at 1× RPM, 2× RPM, higher frequencies, and even at frequencies less than 1× RPM.

These vibrations can indicate severe operational issues if not addressed.

126
Q

What happens when weight is added or removed from a vibrating part, and the vibration changes?

A

The machine is resonating, and the added or removed weight alters the natural frequency, damping or amplifying the resonance.

127
Q

Where does most resonance originate from in a machine?

A

It originates from a non-rotating part and is usually within 3 to 4 meters of the rotating part.

128
Q

How can the natural frequency of pipes be changed to reduce resonance?

A

By adding braces, supports, or expansion joints to stiffen the structure.

129
Q

What frequency is associated with vibration caused by imbalance?

A

1× RPM.

130
Q

How is the amplitude affected by vibration caused by imbalance?

A

Proportional to the degree of imbalance.

131
Q

What is the phase characteristic of vibration caused by imbalance?

A

It is stable and repeatable.

132
Q

What frequencies are associated with misalignment?

A

1× RPM, 2× RPM, or 3× RPM.

133
Q

What percentage of the radial amplitude is common in axial vibrations due to misalignment?

A

50% or more.

134
Q

What phase characteristics are associated with misalignment?

A

Phase differences in 1, 2, or 3 positions, and erratic readings may occur.

135
Q

What type of frequencies are produced by defective anti-friction bearings?

A

Very high, several times the RPM.

136
Q

What is the amplitude characteristic of defective anti-friction bearings?

A

Not large but includes sharp, high-frequency pulses.

137
Q

How does the phase behave in anti-friction bearing problems?

A

The phase is erratic and inconsistent.

138
Q

How does vibration caused by eccentric journals behave in terms of frequency?

A

1× RPM.

139
Q

What is the phase characteristic of vibration caused by eccentric journals?

A

Single-phase characteristic, acting like imbalance.

140
Q

What frequencies are associated with gear problems?

A

Very high, based on gear teeth × RPM.

141
Q

How should gear problems be analyzed?

A

Use velocity or acceleration measurements to detect high-frequency vibrations.

142
Q

What phase characteristic is common with gear problems?

A

The phase is erratic.

143
Q

What are the typical frequencies for mechanical looseness?

A

2× RPM or 4× RPM.

144
Q

What phase readings are common with mechanical looseness?

A

Erratic phase readings at two reference points.

145
Q

What additional issues may accompany mechanical looseness?

A

It may be accompanied by imbalance or misalignment.

146
Q

What vibration frequencies are commonly seen in drive belt problems?

A

1×, 2×, 3×, or 4× RPM of the belts.

147
Q

What can be used to address drive belt vibrations?

A

A strobe light can be used to freeze and observe the belts for corrections.

148
Q

How can electrical vibration forces be identified?

A

Vibration at 1× or 2× synchronous frequency disappears as soon as power is turned off.

149
Q

What is infrared radiation, and how does it relate to temperature?

A

Infrared radiation is emitted by every object, even cold ones. The warmer the object, the more infrared radiation it emits.

Infrared radiation is part of the electromagnetic spectrum.

150
Q

At what temperatures do objects emit visible light, and how is infrared detected?

A

Objects emit visible light only at very high temperatures, such as molten steel in a foundry. Infrared is detected using thermal imaging cameras, which translate the radiation into colors representing temperatures.

Thermal imaging cameras are essential in various applications, including building inspections and night vision.

151
Q

How can combining vibration analysis and oil analysis benefit machine maintenance?

A

Combining the two techniques is an effective way to monitor machine condition, as they can detect different types of failures.

This dual approach allows for more comprehensive diagnostics.

152
Q

What is a significant contaminant in a lubrication system, and how does it affect the system?

A

Water is a significant contaminant that affects viscosity, lubricity, and load-carrying characteristics, and it can lead to oxidation.

Contaminants can severely affect the performance and lifespan of lubrication systems.

153
Q

What is the main cause of oxidation in lubrication systems, and what harm does it cause?

A

The main cause of oxidation is heat. It produces gum, varnish (sticky valves), sludge (blocked passages), and acids (corrosion of parts).

Oxidation can lead to significant mechanical failures if not managed.

154
Q

Where should the oil sample collection point be located in a circulating system?

A

The collection point should be in the live zone where turbulent flow ensures the sample is well-mixed and accurate.

Proper sampling locations are crucial for obtaining representative oil samples.

155
Q

When should an oil sample be taken, and why?

A

The sample should be taken only when the machine is running at normal operating temperature, pressure, speed, and load to ensure accuracy.

Sampling under these conditions minimizes the risk of collecting non-representative oil.

156
Q

What must be avoided when collecting oil samples?

A

Do not collect samples when the machine is cold or unloaded, as it may lead to inaccurate results.

Inaccurate sampling can compromise analysis and lead to poor maintenance decisions.

157
Q

How is contamination in oil measured, and what is the standard unit of measurement?

A

Contamination is measured by particle size and the number of particles of a specific size, using microns (µ) as the unit.

Particle size analysis is a critical aspect of oil analysis.

158
Q

What standards are used for particle count, and what are the sizes included?

A

The ISO cleanliness standard uses particle sizes of 4, 6, and 14 microns.

These standards help in assessing oil cleanliness and potential wear issues.

159
Q

What does the particle count range code (e.g., 18/16/13) indicate?

A

The first number (18): Number of particles >4 microns.
The middle number (16): Number of particles >6 microns.
The last number (13): Number of particles >14 microns.

This coding system is essential for understanding contamination levels in lubricants.

160
Q

Why is thermal analysis (infrared thermography) important for machine diagnostics?

A

It helps monitor machine temperature and identify areas of temperature rise before failure, allowing for corrective maintenance.

Thermal analysis is crucial for preventing unexpected machine breakdowns.

161
Q

What is the primary purpose of thermal imaging cameras in equipment maintenance?

A

To scan and detect the temperature distribution on machinery surfaces quickly and accurately for preventive maintenance.

Preventive maintenance helps in prolonging the life of equipment.

162
Q

What type of image is produced by thermal imaging cameras, and what does it show?

A

The cameras produce a thermogram, which shows the temperature variance across an object’s surface.

Thermograms are essential for visualizing temperature distribution.

163
Q

What are the key components of a thermal imaging camera’s process?

A
  • A special lens focuses infrared light emitted by the object.
  • The infrared detector scans the light.
  • The camera’s electronics process the data into a thermogram.

Each component plays a vital role in accurately capturing thermal data.

164
Q

How can the data collected by a thermal imaging camera be used?

A

The data can be viewed on the camera’s image viewer or transferred to a computer for further analysis and comparison to baseline reference data.

Analyzing data against baseline references aids in identifying anomalies.

165
Q

What is one critical advantage of thermal imaging cameras in machine diagnostics?

A

They provide non-contact temperature monitoring, enabling the identification of problem areas without disrupting machinery operation.

Non-contact monitoring is particularly useful in high-risk environments.

166
Q

What are the four (4) products of oxidation in oil?

A

• Gum
• Varnish
• Sludge
• Acids

167
Q

When an oil sample is removed from a point in a circulating system, what is it called?

A

A live zone sample

168
Q

Where should oil sample collection points NOT be located?

A

• Dead pipe legs
• After filters or separators

169
Q

Should the oil sample bottle always be filled completely full?

A

No, it should not. Room must be left in the container for proper agitation of the sample at the analysis lab.

170
Q

Is infrared radiation visible?

A

No, it is not visible, but it gives off heat.

171
Q

What type of image does a thermal imaging camera produce?

A

A thermogram

172
Q

What happens to mechanical equipment prior to failure?

A

Mechanical equipment tends to rise in temperature prior to failure.

173
Q

What does emissivity refer to in materials?

A

The material’s ability to emit thermal radiation.

174
Q

What does vibration analysis refer to?

A

Detecting, measuring, and analyzing vibration to determine if it is within normal machine parameters.

175
Q

What does oil condition monitoring allow a technician to do?

A

Analyze contamination in the lubricant.

176
Q

What is measured using infrared thermography?

A

Heat being emitted.

177
Q

Can frequency be measured in CPM (cycles per minute)?

A

True.

178
Q

Is Hertz a measurement of frequency?

A

True.

179
Q

What does amplitude measure in vibration analysis?

A

How much.

180
Q

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

A

Phase.

181
Q

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

A

Force.

182
Q

What is unique about imbalance amplitude readings?

A

They are similar in the vertical and horizontal directions.

183
Q

What is the type of resonance that occurs when a shaft or other rotating component reaches its natural frequency called?

A

Critical speed.

184
Q

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

A

Dominant frequency.

185
Q

What is the purpose of a transducer in vibration analysis?

A

To convert vibration into an electrical signal.

186
Q

What are three types of transducers?

A
  • Displacement
  • Velocity
  • Acceleration
187
Q

Describe HVA (Horizontal, Vertical, and Axial) measurements.

A

Vibration measurements taken from horizontal, vertical, and axial positions to analyze overall vibration patterns.

188
Q

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

A

To establish a baseline reference and track trends within the machine.

189
Q

Why should small vibrations at the sides of the dominant frequency on a graph not be ignored?

A

They could indicate impending bearing troubles or other secondary issues.

190
Q

What are some forcing functions

A
  • Impact
  • RPM
  • Friction
  • Pressure
  • looseness/softfoot
  • reciprocating

Bretts Millwright Lovechild (2 decks)

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