CRE Equipment and Tools Knowledge 2

Question 1

Which condition monitoring technique is MOST effective for detecting early-stage bearing defects in rotating machinery?

Accepted Answer

Vibration spectrum analysis

Answer

Vibration spectrum analysis can detect characteristic bearing defect frequencies (BPFI, BPFO, BSF, FTF) long before failure becomes visible or thermal.

Question 2

A laser shaft alignment tool reports an angular misalignment of 0.8 mrad. This value primarily affects which failure mode?

Accepted Answer

Coupling and bearing wear from bending loads

Answer

Angular misalignment introduces cyclic bending loads on couplings and bearings, accelerating wear and fatigue damage.

Question 3

When using an ultrasonic thickness gauge, the measured value is lower than the nominal wall thickness. What is the MOST likely cause?

Accepted Answer

Internal corrosion or erosion reducing wall thickness

Answer

Internal corrosion or erosion removes material from the inner surface, reducing the measured wall thickness without visible external damage.

Question 4

In oil analysis, a high ISO cleanliness code (e.g., 22/20/17) compared to the target (16/14/11) indicates:

Accepted Answer

Excessive particulate contamination requiring filtration or oil change

Answer

A higher ISO cleanliness code means more particles per milliliter, signaling contamination that can accelerate bearing and gear wear.

Question 5

A motor current signature analysis (MCSA) tool detects sidebands at frequencies of line frequency ± 2sf. What does this pattern indicate?

Accepted Answer

Broken rotor bars

Answer

Broken rotor bars produce characteristic sidebands at f_line ± 2sf (where s = slip, f = supply frequency) in the motor current spectrum.

(CRE) Certified Reliability Engineer Practice Test

(CRE) Certified Reliability Engineer Practice Test

CRE Equipment and Tools Knowledge 2