What is vibration phase diagram?

The phase diagram or phase space is a geometric representation of the Hamiltonian function of a dynamic system. It represents the relationship between the potential and kinetic energies at any time.

How the concept of phase angle is used in vibrations?

When vibrating under the influence of a vibratory force, there is a phase angle between the displacement and the force for any given frequency in the spectrum. At resonance the phase angle between the displacement and applied force is either +90-degrees or -90-degrees.

What does 1X vibration mean?

Vibration is any oscillatory motion caused by a restorative force. Free vibration occurs when a bell is rung or a guitar string is plucked. The most common vibration frequency is directly caused by this spinning shaft is dubbed fundamental shaft speed or running speed and is denoted as “1X vibration.”

Which two vibration measures are 180 degrees out of phase?

Destructive interference occurs when the maxima of two waves are 180 degrees out of phase: a positive displacement of one wave is cancelled exactly by a negative displacement of the other wave. The amplitude of the resulting wave is zero.

What is 1X 2X 3X vibration?

A 1X and 2X vibration signal predominant in the axial direction is generally the indicator of a misalignment between two coupled shafts. The spectrum shows high axial vibration at 1X plus some 2X and 3X with 180° phase difference across the coupling in the axial direction.

What is phase angle vibration?

Phase describes the relative timing between two signals. Phase is the angle difference between a measured point and a reference point. Phase is the angle difference measured from the peak of a vibration signal backward in time to the reference trigger point.

What is phase angle of vibration?

Phase is the angle difference measured from the peak of a vibration signal backward in time to the reference trigger point. The following figure shows a phase of 90 degrees and the relationship between a vibration signal and reference signal. The peak of the vibration signal lags 90 degrees behind the trigger point.

What is meant by phase angle?

phase angle: Of a periodic wave, the number of suitable units of angular measure between a point on the wave and a reference point. Usually, at least one full cycle of each wave is plotted, with 360° (2 radians) encompassing one full cycle.

What is FFT in vibration?

The fast Fourier transform (FFT) is an efficient algorithm used to compute a discrete Fourier transform (DFT). This Fourier transform outputs vibration amplitude as a function of frequency so that the analyzer can understand what is causing the vibration.

How is the phase of a vibration measured?

In vibration analysis, phase can be measured using either an absolute or relative reference. Most single channel vibration analyzers can measure absolute phase of a signal, relative to an absolute reference such as a tachometer pulse.

How is phase lag related to time constants?

As the figure indicates, the response is slow (the large time constants were an early indication of this behavior), with a peak response slightly larger than 1.2 after approximately 20 s and a steady-state response reached after 90 s. The phase-lag compensator has a negative phase angle and so is used to subtract phase from an uncompensated system.

How does phase lag affect the P + I controller?

This compensator improves the static error of the feedback system, similarly to the P + I controller. The lag compensator limits the low-frequency amplification (gain) of the P + I controller, which produces a minimal effect on the transient response, particularly when the zero-pole couple is close to the origin.

How does phase lag improve the stability of a feedback system?

Phase-lag compensation can improve/realize the stability of an existing feedback system by reducing the high-frequency gain to a negative value from a positive value, at a phase angle of −180°.