Predictive & Preventive Maintenance Flashcards
7 cards from real MMC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Predictive & Preventive Maintenance flashcards as text
Motor current signature analysis (MCSA) is primarily used to detect:
Answer: Mechanical faults such as broken rotor bars and bearing defects
MCSA analyzes current waveform signatures to identify mechanical anomalies like broken rotor bars, eccentricity, and bearing faults without physical contact.
Which vibration frequency is generated by a rolling element bearing with a defective outer race?
Answer: Ball pass frequency outer race (BPFO)
A defect on the outer race produces impacts at the ball pass frequency outer race (BPFO), a calculable frequency based on bearing geometry and shaft speed.
What is the key advantage of thermographic surveys conducted during peak electrical load conditions?
Answer: Thermal anomalies are more pronounced under higher current flow
Resistance-related heating (I²R losses) increases with current, making loose connections and overloaded components easier to detect at higher loads.
A preventive maintenance program shows high PM compliance but equipment failures have not decreased. The most likely root cause is:
Answer: PM tasks are not matched to actual failure modes
If PM tasks do not address the dominant failure modes of the equipment, completing them on schedule will not reduce failure frequency.
In oil analysis, a high total base number (TBN) depletion rate in engine oil indicates:
Answer: Acid neutralization capacity is being consumed rapidly, suggesting contamination
TBN measures the oil's remaining alkaline reserve to neutralize acids; rapid depletion signals acid production from combustion by-products or contamination.
Which PM optimization approach uses failure mode and effects analysis (FMEA) to justify maintenance task selection?
Answer: Reliability-Centered Maintenance (RCM)
RCM uses FMEA to identify failure modes, their effects, and consequences, then selects tasks that are technically and economically justified for each failure mode.
An equipment operator notices a new high-pitched squeal from a conveyor drive motor. This is best categorized as:
Answer: Operator-based condition monitoring that should be documented and reported
Operators are a critical sensing resource in condition monitoring; unusual sounds should be documented and reported to maintenance for evaluation.