Predictive Maintenance Technologies Flashcards
7 cards from real CMRT 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 Maintenance Technologies flashcards as text
Motor Current Signature Analysis (MCSA) detects broken rotor bars by looking for sideband frequencies located at:
Answer: (1 ± 2s) × line frequency, where s is slip
Broken rotor bar sidebands appear at (1 ± 2s) × line frequency in the motor current spectrum, where s is the per-unit motor slip.
Acoustic emission (AE) testing is most commonly used in predictive maintenance to detect:
Answer: Structural crack propagation and active plastic deformation
Acoustic emission sensors detect the burst energy released during active crack growth or plastic deformation, providing warning of structural failure before it occurs.
When performing laser shaft alignment, an angular misalignment condition is corrected by:
Answer: Adding or removing shims under the feet to change the shaft angle
Angular misalignment (shaft centerlines not parallel) is corrected by shimming under the feet of the moveable machine to change the shaft's angle relative to the driver.
In process parameter monitoring, which parameter is the most direct indicator of pump cavitation?
Answer: Discharge pressure pulsation and elevated broadband vibration
Cavitation produces broadband vibration increases and characteristic pressure pulsations as vapor bubbles collapse implosively within the pump.
Eddy current testing (ECT) is best suited for detecting defects in:
Answer: Non-ferromagnetic conductive materials like aluminum or copper tubing
Eddy current testing requires electrically conductive materials; it works best on non-ferromagnetic conductors like aluminum, copper, and austenitic stainless steel tubes.
The P-F interval in a PdM program represents:
Answer: The time between detection of a potential failure and occurrence of functional failure
The P-F interval is the time between when a potential failure can first be detected (P) and when it degrades to a functional failure (F), defining the inspection frequency needed.
Which nondestructive testing (NDT) method uses sound waves at frequencies typically between 0.5 and 25 MHz to measure wall thickness and detect internal flaws?
Answer: Ultrasonic testing (UT)
Ultrasonic testing uses high-frequency sound waves that travel through the material and reflect off internal discontinuities or the back wall to measure thickness and detect flaws.