MMC Predictive & Preventive Maintenance 2 — Questions and Answers
Question 1: Which oil analysis parameter is most useful for detecting bearing wear in rotating equipment?
- Viscosity index
- Ferrographic particle count (Correct answer)
- Total acid number
- Flash point
Correct answer: Ferrographic particle count
Ferrographic particle count identifies ferrous wear particles shed by bearings, providing early warning of mechanical degradation.
Question 2: A PM task requiring lubrication every 500 operating hours is best triggered by which method?
- Calendar date
- Production output count
- Equipment runtime meter (Correct answer)
- Technician judgment
Correct answer: Equipment runtime meter
An equipment runtime meter directly tracks actual operating hours, ensuring lubrication is performed at the correct interval regardless of calendar time.
Question 3: What does a rising trend in ultrasonic decibel readings from a steam trap most likely indicate?
- Normal condensate drainage
- Trap is functioning optimally
- Trap is blowing live steam (failed open) (Correct answer)
- Insulation improvement
Correct answer: Trap is blowing live steam (failed open)
A steam trap failed open passes live steam continuously, generating elevated high-frequency ultrasonic noise detectable with an ultrasonic instrument.
Question 4: In a preventive maintenance program, 'task bundling' refers to:
- Grouping multiple PM tasks on the same equipment during a single shutdown (Correct answer)
- Issuing PMs in batches at month-end
- Assigning multiple technicians to one work order
- Combining corrective and preventive work orders in CMMS
Correct answer: Grouping multiple PM tasks on the same equipment during a single shutdown
Task bundling reduces total downtime by performing several PM activities on one piece of equipment during a single planned outage.
Question 5: Which condition monitoring technique measures changes in the physical properties of lubricating oil without sending samples to a lab?
- Spectrographic analysis
- In-line oil quality sensor (Correct answer)
- Ferrography
- Patch test
Correct answer: In-line oil quality sensor
In-line oil quality sensors measure real-time parameters such as dielectric constant, moisture, and viscosity directly in the lubrication system.
Question 6: The primary purpose of establishing P-F intervals in predictive maintenance is to:
- Schedule technician shifts efficiently
- Ensure work orders are closed on time
- Define the window between potential failure detection and functional failure (Correct answer)
- Determine equipment replacement cost
Correct answer: Define the window between potential failure detection and functional failure
The P-F interval is the time between when a potential failure becomes detectable (P) and when functional failure occurs (F), defining how much lead time maintenance has.
Question 7: Which type of preventive maintenance task is considered 'on-condition' rather than time-based?
- Replacing filters every 90 days
- Overhauling a pump at 10,000 hours
- Inspecting belt tension and replacing only if out of tolerance (Correct answer)
- Changing motor oil on a fixed calendar schedule
Correct answer: Inspecting belt tension and replacing only if out of tolerance
On-condition tasks defer replacement until an inspection reveals the item has reached a defined threshold, rather than replacing at a fixed interval.
MMC Predictive & Preventive Maintenance 2
Which oil analysis parameter is most useful for detecting bearing wear in rotating equipment?