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
In infrared thermography, what is the primary significance of emissivity when measuring surface temperatures?
Answer: It affects the accuracy of the temperature reading if set incorrectly
Emissivity is the ratio of energy emitted by a surface to that of a perfect blackbody; an incorrect emissivity setting causes significant temperature measurement errors.
During an electrical panel thermography inspection, a single-phase connection shows a temperature of 85°C while the other two phases are at 35°C. This most likely indicates:
Answer: Loose or high-resistance connection
A single hot spot at one connection point with significantly elevated temperature compared to similar phases indicates a loose or corroded high-resistance connection.
Airborne ultrasound technology detects faults primarily by sensing:
Answer: High-frequency sound in the 20–100 kHz range
Ultrasound instruments detect high-frequency acoustic emissions (20–100 kHz) produced by turbulent flow, arcing, or friction that are inaudible to the human ear.
Which lubricant oil analysis test is most directly used to detect ferrous wear particles from gear or bearing surfaces?
Answer: Ferrography or particle count
Ferrography and particle count tests quantify wear metal particles in the oil, directly indicating the rate of metallic component wear.
In motor circuit analysis (MCA), a low megohm reading between a motor winding and ground indicates:
Answer: Insulation degradation to ground
Megohmmeter (Megger) testing measures insulation resistance; low values indicate moisture ingress, contamination, or physical breakdown of winding insulation to ground.
Which condition monitoring technology is most effective for detecting compressed air or steam leaks in pressurized systems?
Answer: Airborne ultrasound
Airborne ultrasound detects the turbulent flow noise created at leak points in pressurized systems, making it highly effective for leak detection.
The viscosity index (VI) of an oil describes:
Answer: How much the oil's viscosity changes with temperature
Viscosity index is a measure of how much an oil's viscosity changes with temperature; a higher VI means the viscosity is more stable across temperature ranges.