What is the difference between preventive maintenance PM and predictive maintenance PdM?

What is the difference between preventive maintenance PM and predictive maintenance PdM?

• A. PM is time- or usage-based tasks; PdM uses condition data to decide when maintenance is needed.
• B. PM uses condition data, PdM is random.
• C. PM and PdM are the same.
• D. PdM relies on calendar schedules.

Answer: (A)

Preventive maintenance is planned using a calendar or usage-based schedule, performing tasks at fixed intervals regardless of the current condition. Predictive maintenance, by contrast, relies on machine-condition data (such as vibration, temperature, oil analysis, or wear readings) to forecast when a component will fail and schedule service just before that predicted failure. The key idea is that PM follows a set schedule, while PdM is driven by data that indicate deterioration and a need for action. The other ideas mix up how condition data and schedules are used—not all maintenance is random, and PdM isn’t based on a fixed calendar.

Preventive maintenance is planned using a calendar or usage-based schedule, performing tasks at fixed intervals regardless of the current condition. Predictive maintenance, by contrast, relies on machine-condition data (such as vibration, temperature, oil analysis, or wear readings) to forecast when a component will fail and schedule service just before that predicted failure. The key idea is that PM follows a set schedule, while PdM is driven by data that indicate deterioration and a need for action. The other ideas mix up how condition data and schedules are used—not all maintenance is random, and PdM isn’t based on a fixed calendar.