CMRT Equipment Reliability 3 — Questions and Answers
Question 1: In a Failure Mode and Effects Analysis (FMEA), the Risk Priority Number (RPN) is calculated by multiplying which three factors?
- Severity, Occurrence, Detection (Correct answer)
- Frequency, Impact, Cost
- Probability, Consequence, Exposure
- Likelihood, Severity, Mitigation
Correct answer: Severity, Occurrence, Detection
RPN = Severity × Occurrence × Detection, and higher RPN values indicate higher priority failure modes for corrective action.
Question 2: Which root cause analysis technique uses a diagram resembling a fish skeleton to organize potential causes of a failure?
- Fault Tree Analysis
- Ishikawa diagram (Correct answer)
- Pareto chart
- 5-Why analysis
Correct answer: Ishikawa diagram
The Ishikawa (fishbone) diagram organizes potential causes into major categories branching from the effect, resembling a fish skeleton.
Question 3: A bearing fails prematurely showing spalling on one race. What failure mechanism is most likely responsible?
- Adhesive wear
- Fatigue (Correct answer)
- Corrosion
- Erosion
Correct answer: Fatigue
Spalling (surface pitting and material breakaway) on bearing races is a classic sign of rolling contact fatigue.
Question 4: Which failure analysis method uses Boolean logic to evaluate combinations of component failures that lead to a top-level system failure?
- FMEA
- RCM
- Fault Tree Analysis (Correct answer)
- Weibull analysis
Correct answer: Fault Tree Analysis
Fault Tree Analysis uses AND/OR logic gates to graphically map how combinations of lower-level failures cause a specific top-level undesired event.
Question 5: When performing a '5-Why' analysis on a gearbox failure, the primary purpose is to:
- Quantify the financial impact of the failure
- Identify the physical, human, and latent root causes (Correct answer)
- Rank all failure modes by severity
- Determine the statistical failure distribution
Correct answer: Identify the physical, human, and latent root causes
The 5-Why method drills down through successive 'why' questions to uncover physical, human, and latent systemic root causes.
Question 6: A shaft seal fails due to excessive radial load causing misalignment. According to RCA classification, this is best categorized as which type of root cause?
- Latent root cause
- Physical root cause (Correct answer)
- Human root cause
- Systemic root cause
Correct answer: Physical root cause
The physical root cause is the tangible, material condition (excessive radial load causing misalignment) that directly produced the failure.
Question 7: Which FMEA type is performed during the design phase to identify potential failure modes before equipment is manufactured?
- Process FMEA
- Design FMEA (Correct answer)
- System FMEA
- Functional FMEA
Correct answer: Design FMEA
Design FMEA (DFMEA) is conducted during product design to identify and mitigate failure modes before manufacturing begins.
CMRT Equipment Reliability 3
In a Failure Mode and Effects Analysis (FMEA), the Risk Priority Number (RPN) is calculated by multiplying which three factors?