Maintenance, Inspection, and Testing
Core concepts
Know the maintenance cycle: routine condition monitoring, planned outages, borescope and nondestructive examination, blade and seal inspection, bearing clearance checks, and valve overhaul. Understand predictive tools: vibration analysis, oil analysis, thermography, and performance testing. Candidates must know the purpose of periodic tests - overspeed trip test, valve stroke and response tests, lube oil pump auto-start test, and protection channel tests. Recognize nondestructive methods: dye penetrant, magnetic particle, ultrasonic, and radiographic inspection, and which materials each suits.
Traps
Questions often confuse a functional test with a calibration. Another trap is testing protection while the unit is online: some tests require the unit offline or on turning gear. Remember that a valve stroke test verifies movement and timing, not necessarily flow capacity. Watch for the claim that a test proves reliability - it demonstrates function at that moment only.
Worked rule of thumb
Use a simple trend rule: if bearing vibration rises by more than about 25% from baseline at the same load and temperature, schedule investigation before the next outage. For oil, a rapid drop in flash point or rise in water content signals immediate action.
Exam focus
Be able to select the inspection method for a defect type and to state what each periodic test actually proves.