Plymon Flashcards
How are predictive programs justtfied?
Cost savings due to machine uptime and reduced secondary failures.
What is considered a measure of vibration severity?
Amplitude: Displacement (mils)
Velocity (ips)
Acceleration (g’s)
How are faults identified when viewing vibration data?
Frequency:
Hz-Cycles per second
CPM- cycles per minute
Orders- normalized to 1xRPM
What is a Time Waveform?
A plot of amplitude verses time.
What is a spectrum?
A plot of amplitude verses frequency.
What is a trend plot?
A plot of vibration amplitude over time (commonly the overall value)
How could motions in a time wave form be described?
Periodic, Impacting, Harmonic, Random, Pulsating (beat frequency), Ring down (impact test), Modulation,etc.
In most predictive maintenance programs on industrial machines. What measure is most often used to evaluate vibration?
Velocity, as it is more sensitive to vibration amplitudes across the frequency range of common machines.
How are the Period of vibration and the frequency of vibration related?
They are reciprocals of each other.
1/Period in seconds is equal to the frequency in cycles per second.
1/ frequency in cycles per second equals the period in seconds.
“Ten cycles per second” is equal to what frequency unit.
10 Hertz (Hz)
Convert 10 Hz (cycles per second) to CPM (cycles per minute)
10Hz x 60 (seconds/ minute)=600CPM
If the machine speed is 3600 rpm and the vibration is occurring at 7200 CPM, What order would the vibration be considered.
2 Orders- 7200(vibration) /3,600(1x RPM)=2
What components are required to acquire phase data on a machine?
Vibration transducer and a trigger (speed reference) or 2 vibration transducers acquiring data simultaneously.
Rank the transducer mounting methods from lowest to highest.
Hand probe, 2-rail magnet, flat magnet, epoxy mount, stud mount.
What transducer mounting method is accepted as the most convenient for normal vibration data collection.
Magnet mount.
What transducer mounting method is best for high frequency analysis.
Stud mount.
How many degrees are in one complete cycle of vibration?
360°