Deck 5: Vibration Measurement and Analysis

Question 1

From the given data, calculate the unbalanced centrifugal force in N s2 Distance from shaft = 0.2 m Mass = 100 kg Rotating speed = 1000 rpm.

A)20
B)2×10^⁷
C)200
D)20000

Answer 1

200

Question 2

Let the disturbing mass be 50 Kg, with radius of rotation = 0.1m, if one of the balancing mass is 30 Kg at a radius of rotation 0.1m then find the other balancing mass situated at a distance of 0.2m.

A)80
B)40
C)20
D)10

Answer 2

10

Question 3

What is the function of frequency analyzer?

A)It analysis noise signal in frequency domain into various frequency bands by magnetically separating the signal
B)It analysis noise signal in frequency domain into various frequency bands by electronically separating the signal
C)It analysis noise signal in frequency domain into various frequency bands by electromagnetically separating the signal
D)None of the above

Answer 3

It analysis noise signal in frequency domain into various frequency bands by electronically separating the signal

Question 4

What is the function of the controller in active vibration isolation systems?

A)Detect vibrations to be controlled
B)Reposition the masses
C)Interpret detected vibrations and execute commands
D)All of the above

Question 5

Temperature monitoring technique uses which of the following devices to measure temperature of the machining surfaces?

A)Pyrometers
B)Thermocouples
C)Thermometers
D)All of the above

Question 6

Which of the following statements is true about stroboscope?

A)Stroboscope is non-contact type frequency instrument
B)Stroboscope can measure frequency upto 5 Hz
C)Stroboscope uses electromagnetic radiations to measure frequency
D)All of the above

Question 7

Which type of frequency measuring instrument has multiple reeds of different natural frequency to measure vibrations?

A)Fullarton tachometer
B)Frahm Tachometer
C)Both a. and b.
D)None of the above

Question 8

Which of the following instruments measure amplitude of a vibrating body?

A)Vibrometers
B)Seismometer
C)Both a. and b.
D)None of the above

Question 9

Which of the following vibrometers have frequency ratio (?/?n) << 1?

A)Accelerometers
B)Velometers
C)Both a. and b.
D)None of the above

Question 10

Which type of monitoring system uses stroboscope to measure speed of the machine?

A)Portable condition monitoring system
B)Basic condition monitoring system
C)Computer based condition monitoring system
D)None of the above

Question 11

Seismometer can be used to measure acceleration of any instrument only if _____

A)it's natural frequency is high
B)it generates output signal which is proportional to relative acceleration of the vibrating object
C)both a. and b.
D)none of the above

Question 12

In FFT Spectrum Analyzer, the D/A converter is used to ________.

A)reject unwanted signals
B)sets the level of the signals to be fed to the A/D converter
C)convert analog signals into digital signals
D)converts digital signals into analog signals

Question 13

In FFT Spectrum Analyzer, the A/D converter is used to ________.

A)reject unwanted signals
B)sets the level of the signals to be fed to the A/D converter
C)convert analog signals into digital signals
D)converts digital signals into analog signals

Question 14

In FFT Spectrum Analyzer, the attenuator is used to ________.

A)reject unwanted signals
B)sets the level of the signals to be fed to the A/D converter
C)convert analog signals into digital signals
D)converts digital signals into analog signals

Question 15

In FFT Spectrum Analyzer, the filter is used to ________.

A)reject unwanted signals
B)sets the level of the signals to be fed to the A/D converter
C)convert analog signals into digital signals
D)converts digital signals into analog signals

Question 16

FFT analyzer can be used to find the ___________.

A)natural frequencies
B)mode shapes
C)both natural frequencies and mode shapes
D)none of the above

Question 17

Fourier transform is a mathematical procedure to obtain the __________ of a given input signal.

A)spectrum
B)integration
C)difference
D)none of the above

Question 18

In FFT Spectrum Analyzer, FFT stands for _______.

A)Frequency Fourier Transform
B)Fast Fourier Transmission
C)Frequency Fourier Transmission
D)Fast Fourier Transform

Question 19

From the following, which one is used in an accelerometer?

A)Dielectric crystals
B)Piezoelectric crystals
C)Optic crystals
D)Diamond

Question 20

The accelerometers are commonly used in vibration measurement due to their ___________.

A)small size and low sensitivity
B)the large size and high sensitivity
C)the large size and low sensitivity
D)small size and high sensitivity

Question 21

Which instrument is used to record building vibrations or vibrations of huge structures like railway bridges?

A)Stroboscope
B)Accelerometer
C)Vibrometer
D)None of the above

Question 22

Vibration measuring instruments are classified on the basis of ____________.

A)contact between the vibrating system and measuring instrument
B)the requirement of power source
C)method of measurements
D)all of the above

Question 23

From the following, which one is also known as low-frequency Transducer?

A)Stroboscope
B)Accelerometer
C)Vibrometer
D)None of the above

Question 24

From the following, which one is a type of vibration measuring instrument?

A)Mechanical
B)Electrical
C)Magnetic
D)All of the above