CMRT Equipment Reliability 4

Question 1

A vibration spectrum shows a dominant frequency at exactly 1× running speed with high amplitude. What condition does this most likely indicate?

Accepted Answer

Mass unbalance

Answer

A dominant 1× running speed frequency is the classic signature of mass unbalance, where rotating mass is not distributed evenly around the shaft axis.

Question 2

In oil analysis, which property indicates the oil's resistance to flow at operating temperature?

Accepted Answer

Viscosity

Answer

Viscosity measures the oil's internal resistance to flow and is the most critical property for maintaining adequate lubricant film thickness.

Question 3

An infrared thermography scan reveals a hot spot on a three-phase motor control panel. What is the most appropriate next action?

Accepted Answer

Document the finding and schedule corrective maintenance based on severity

Answer

Thermography findings should be documented with severity classification, then corrective action should be scheduled based on risk before the fault progresses to failure.

Question 4

Which ultrasound condition monitoring technique is most effective for detecting early-stage bearing defects and compressed-air leaks?

Accepted Answer

Airborne ultrasound

Answer

Airborne ultrasound detects high-frequency sound waves (typically 20–100 kHz) produced by bearing defects, electrical arcing, and pressurized leaks.

Question 5

Wear particle analysis in oil shows an increase in large (>15 µm) ferrous particles with a cutting wear morphology. What does this indicate?

Accepted Answer

Severe adhesive or abrasive wear in progress

Answer

Large cutting-type ferrous particles indicate abrasive or adhesive wear where a hard material is cutting through a softer surface under load.

(CMRT) Certified Maintenance and Reliability Technician Practice Test

(CMRT) Certified Maintenance and Reliability Technician Practice Test

CMRT Equipment Reliability 4