CVA Data Collection & Instrumentation

Question 1

What is the primary advantage of an ICP® (Integrated Circuit Piezoelectric) accelerometer over a charge-mode accelerometer?

Accepted Answer

ICP sensors have built-in signal conditioning and can use long, low-cost coaxial cables without signal degradation

Answer

ICP sensors have a wider frequency range extending to ultrasonic frequencies

Answer

ICP sensors are immune to thermal transients and pyroelectric effects

Answer

ICP sensors do not require a power source and are completely passive devices

Question 2

What is the transverse sensitivity of an accelerometer?

Accepted Answer

The response of the accelerometer to vibration perpendicular to its primary measurement axis

Answer

The sensitivity of the accelerometer to vibration in the intended measurement axis

Answer

The change in sensitivity as a function of temperature

Answer

The frequency at which the accelerometer sensitivity drops by 3 dB

Question 3

What is the resonant frequency of an accelerometer, and why does it matter for measurements?

Accepted Answer

The frequency at which the sensor output is maximum; usable range ends well below this to avoid amplitude errors

Answer

The frequency at which the accelerometer requires recalibration

Answer

The natural frequency of the mounting surface that affects all measurements equally

Answer

The lowest frequency at which the accelerometer can detect vibration

Question 4

Which accelerometer mounting method typically provides the highest usable frequency range?

Accepted Answer

Threaded stud mount directly into the machine surface

Answer

Magnetic mount

Answer

Adhesive mount (epoxy or wax)

Answer

Hand-held probe with soft tip

Question 5

What is a proximity probe (eddy current sensor) primarily used for in rotating machinery instrumentation?

Accepted Answer

Measuring the relative displacement between the shaft and the bearing housing in fluid-film bearing machines

Answer

Measuring surface temperature of rotating shafts

Answer

Detecting roller element bearing defects in the high-frequency range

Answer

Measuring torsional vibration of rotating shafts

Question 6

What is the purpose of a low-pass anti-aliasing filter in a vibration data acquisition system?

Accepted Answer

To remove frequency components above the Nyquist frequency before analog-to-digital conversion, preventing aliasing

Answer

To remove low-frequency trends and DC offset from the signal before digitization

Answer

To compensate for the frequency response of the accelerometer mounting

Answer

To apply digital integration for converting acceleration to velocity signals