CVA Cheat Sheet 2026

The 30 highest-yield CVA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the primary purpose of adding mass or stiffness to a structure to address a resonance problem? → To shift the natural frequency away from the excitation frequency to detune the resonance
2. A proximity probe system has a typical sensitivity of 200 mV/mil. What does it measure? → Shaft displacement relative to the probe mounting
3. Which window gives the best amplitude accuracy for a steady sinusoid that falls between two FFT bins? → Flat top
4. Which type of shaft misalignment produces high vibration predominantly in the axial direction at 1× and 2× running speed? → Angular misalignment
5. What is the unit of the Y-axis in a power spectral density (PSD) plot? → g² / Hz
6. Gas and steam turbines, turbo-compressors, and machine-tool drives are typically balanced to which ISO 1940-1 grade? → G2.5
7. What does FFT stand for in vibration analysis? → Fast Fourier Transform
8. Which spectral feature is most characteristic of pump cavitation? → Random broadband high-frequency energy, often with a raised noise floor
9. Which technique is most effective for detecting the earliest stage of rolling element bearing wear? → High-frequency methods such as enveloping, PeakVue, or spike energy
10. Which parameter is used in high-frequency bearing diagnostics to quantify the overall impulsiveness of the bearing signal? → Kurtosis
11. A centrifugal pump shows high vibration at vane pass frequency. Which cause is most likely? → Insufficient gap between impeller vanes and the cutwater/diffuser
12. What issue does excessive heat often point to? → Bearing or lubrication problems
13. During a soft foot check, which procedure is typically used? → Loosen one hold-down bolt at a time and measure foot movement with a dial indicator
14. ISO 13381-1 provides guidance on which aspect of condition monitoring? → Prognostics, estimating remaining useful life
15. What characteristic vibration pattern is associated with shaft misalignment? → Elevated 2× running speed, often with high axial vibration at 1× and 2×
16. A rolling element (ball) spin defect frequency is most often accompanied by sidebands spaced at which frequency? → Fundamental train frequency (FTF)
17. A 4-pole, 60 Hz induction motor runs at 1,780 RPM. What is the pole pass frequency? → About 1.33 Hz
18. The fundamental train frequency (FTF, cage frequency) of a rolling element bearing typically falls at what fraction of shaft speed? → About 0.4X
19. An analyzer is set to Fmax = 1000 Hz with 400 lines of resolution. What is the frequency resolution (bin width)? → 2.5 Hz
20. What device measures equipment temperature without contact? → Infrared thermometer or camera
21. In rolling element bearing failure analysis, what does 'spalling' refer to? → Fatigue cracking and flaking of material from bearing raceways or rolling element surfaces
22. When using the rim and face dial indicator method, what does the 'face' indicator primarily measure? → Angular misalignment between the two shafts
23. On an AC induction motor fed at 60 Hz, a dominant peak at 120 Hz that disappears instantly when power is cut points to what type of problem? → Electrical problem such as stator eccentricity or soft-foot-induced air gap variation
24. What do non-contact proximity probes on a fluid-film bearing machine measure? → Relative displacement of the shaft with respect to the bearing housing
25. When a rotor passes through a natural frequency during a coastdown, how does phase typically change? → It shifts about 90 degrees at resonance and about 180 degrees overall
26. What is the first step in troubleshooting machinery issues? → Identify and understand the symptoms
27. In an orbit plot with a once-per-revolution keyphasor mark, what is the most likely cause of a strongly flattened, elliptical 1× orbit? → Asymmetric support stiffness, preload, or misalignment
28. A machine with sleeve bearings shows a peak at 0.44x running speed that tracks speed as RPM changes. Which condition is indicated? → Oil whirl
29. Most FFT analyzers sample at what multiple of Fmax so the anti-aliasing filter has room to roll off? → 2.56 times
30. ISO 2954 specifies requirements for which item? → Instruments for measuring vibration severity on rotating and reciprocating machines