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Millwright P4 Vibration And Friends > Vibration Section 4 > Flashcards

Vibration Section 4 Flashcards

1
Q

What is vibration analysis?

A

Refers to detecting, measuring and analyzing the vibration and determining whether it is within normal machine operation.

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2
Q

What are possible sources of vibration?

A

Misalignment, imbalance, bearing damage, gear problems and resonance.

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3
Q

Oil condition monitoring allows the tech to?

A

Analyze contamination in the lubricant.

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4
Q

Infrared thermography allows for the measurement of?

A

Heat being emitted.

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5
Q

How can Frequency be measured?

A

CPs CPM Hz

1cps = 1 Hz = 60cpm

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6
Q

What is Amplitude?

A

How Much.

Indicates how much a machine is vibrating.

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7
Q

The three measurements of Amplitude?

A

Displacement
Velocity
Acceleration

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8
Q

What is Displacement?

What are the measurements?

A

The total distance a vibrating part moves either side of its natural axis

Measured in
1mil=0.001 inch
1micron=0.001mm

Total distance measured peak to peak

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9
Q

What is Velocity?

What are the measurements?

A

The rate of change of displacement for a given time.

Measured in
In/sec or IPS
Mm/s

Measure at max velocity, center of neutral axis
Used between 600cpm-60,000cpm

Combination of displacement(how far it moves) and frequency(how often)

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10
Q

What is Acceleration?

What are the measurements?

A

Is the rate of change in velocity and is measured in Gs force.

Measured in
9.8m/sec squared
32 ft/ sec squared

Maximum acceleration occurs at each peak of the sign, zero acceleration is at the Center where max velocity is.

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11
Q

How do you change a vibrational signature?

A

By changing either the mass or the stiffness of an object.

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12
Q

What is a sine wave?

A

A graphic depiction of a vibration cycle.

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13
Q

What is a Frequency?

A

How often an event happens in a unit of time or in one cycle.

The frequency of a vibration is the number of full cycles that occur during a specified time.

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14
Q

On a vibrational read out, what is the largest line or frequency referred to as?

A

Predominant or fundamental frequency.

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15
Q

What is phase in vibration characteristics?

A

Is the time relationship between two related events and is measured or expressed in degrees.

Relationship between displacement, velocity, and acceleration is referred to as phase.

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16
Q

What does it mean to be in phase?

A

Both places (taking readings from two locations) are vibrating up and down at the same time.

This phase Angle is considered 0 degrees.

17
Q

What does it mean to be out of phase?

A

If the vibration points are out of phase it means both pick up locations are not moving in the same direction at the same time.

The phase Angle could be 45 degrees or 180 for example.

18
Q

Is the frequency at which an object naturally vibrates when force is introduced?

A

Natural frequency.

19
Q

What is Resonance?

A

Describes the phenomenon of increased amplitude that occurs when the frequency of a periodic applied force is equal or close to a natural frequency of the system on which it acts.

20
Q

What is Critical Speed?

A

Is when a shaft or rotor for example, reaches or nears its natural frequency. Reaches a point of resonance and there is a marked increase in vibration which could destroy the equipment.

21
Q

What is a Harmonic?

A

Is a multiple or sub-multiple of the fundamental frequency.

22
Q

What is a Synchronous vibration?

A

Corresponds to a frequency that is a hole multiple of the RPM speed, phase locked in ie 1x rpm and 2x rpm

23
Q

What is a non-Synchronous vibration?

A

Are frequencies that are not hole multiples of the RPM speed of the machine.

24
Q

What is Sub-Synchronous?

A

Are frequencies that occur at less than RPM speed of machine.

25
Q

What is a baseline?

A

Is a normal standard of vibration for a particular machine.

It’s a ref point to base readings from.

26
Q

What is the process of Vib analysis?

A

Converting a vibration into an electrical signal with the use of a transducer.

27
Q

What are the ways a Transducer can be mounted?

A

Stud mount
Magnetic pickup mount
Hand held probe
Shaft rider accessory

Millwright P4 Vibration And Friends (1 decks)

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