CVA Shaft Alignment & Machinery Installation

Question 1

Which type of shaft misalignment produces high vibration predominantly in the axial direction at 1× and 2× running speed?

Accepted Answer

Angular misalignment

Answer

Angular misalignment causes the shaft ends to meet at an angle, generating strong axial forces that produce elevated 1× and 2× vibration in the axial direction.

Question 2

What is the most common vibration frequency signature associated with parallel (offset) misalignment?

Accepted Answer

Dominant 2× radial vibration

Answer

Parallel misalignment typically produces a dominant 2× radial vibration component because the coupling must correct twice per revolution to accommodate the offset.

Question 3

During a soft foot check, what is the maximum acceptable dial indicator reading before corrections must be made?

Accepted Answer

0.002 inch (0.05 mm)

Answer

The industry-accepted threshold for soft foot is 0.002 inch (0.05 mm); readings above this value indicate the machine frame is distorted and must be corrected before alignment proceeds.

Question 4

What is 'soft foot' in the context of machinery installation?

Accepted Answer

A condition where one or more machine feet do not make full contact with the baseplate when hold-down bolts are tightened

Answer

Soft foot occurs when tightening hold-down bolts causes the machine frame to distort because one or more feet do not sit flush on the baseplate, inducing internal stresses and misalignment.

Question 5

Which alignment method mounts two dial indicators on the coupling hub of each machine and measures runout as the shafts are rotated together?

Accepted Answer

Reverse indicator method

Answer

The reverse indicator method places a dial indicator on each shaft pointing back toward the opposite machine, allowing both parallel and angular misalignment to be calculated simultaneously with high accuracy.

CVA - Certified Vibration Analyst Practice Test

CVA - Certified Vibration Analyst Practice Test

CVA Shaft Alignment & Machinery Installation