CVA Shaft Alignment & Machinery Installation 3

Question 1

When using the rim and face dial indicator method, what does the 'face' indicator primarily measure?

Accepted Answer

Angular misalignment between the two shafts

Answer

Parallel (radial) offset between the two shaft centerlines

Answer

Coupling runout due to manufacturing defects

Answer

Axial float of the shaft

Question 2

A machine exhibits high 1× vibration that is equal in amplitude in both the horizontal and vertical radial directions and is also high in the axial direction. This pattern most likely indicates:

Accepted Answer

Combined angular and parallel misalignment

Answer

Pure parallel misalignment

Answer

Unbalance

Answer

Bearing inner race defect

Question 3

What is the function of a 'spacer' or 'spool piece' in a shaft coupling, particularly for alignment purposes?

Accepted Answer

To provide axial distance between the driver and driven machine hubs, allowing removal of the coupling element without moving either machine and accommodating thermal growth

Answer

To increase the torsional stiffness of the drive train

Answer

To reduce vibration transmission between machines

Answer

To serve as a safety shear point in case of overload

Question 4

What effect does 'pipe strain' have on a pump and its alignment?

Accepted Answer

External piping forces distort the pump casing, inducing misalignment and soft foot that will return even after correct alignment is performed

Answer

Pipe strain only affects the pump impeller, not the alignment

Answer

Pipe strain improves alignment stability by constraining the pump position

Answer

Pipe strain only occurs during startup and has no effect at steady-state operation

Question 5

During alignment verification after tightening hold-down bolts, which phenomenon can cause the alignment to change from the pre-tightened values?

Accepted Answer

Soft foot distorting the machine frame and repositioning the shaft centerline as bolts are torqued

Answer

Coupling backlash shifting the shaft position

Answer

Thermal runout of the dial indicator

Answer

Magnetic coupling between the shafts

Question 6

What is the primary advantage of laser alignment systems over traditional dial indicator methods?

Accepted Answer

Laser systems eliminate bracket sag error and provide real-time digital readout of misalignment in all planes simultaneously with higher repeatability

Answer

Laser systems can align machines while they are running at full speed

Answer

Laser systems are less expensive than dial indicator equipment

Answer

Laser systems do not require the shafts to be rotated during measurement

Question 7

When aligning a horizontal pump-motor set, which machine is typically moved to achieve alignment, and why?

Accepted Answer

The motor (driver) is moved because the pump is fixed by its piping connections and process requirements

Answer

The pump is moved because it is lighter and easier to reposition

Answer

Both machines are moved equally to distribute the correction

Answer

The machine with the lowest vibration is moved to minimize disruption