Shaft Average Centerline and DC Data Plots
March 9 2011 -
Richard Thomas, P.E.
Most vibration data plots, including: Timebase, Orbit, Polar, and Bode, present dynamic vibration data. For seismic transducers, this dynamic data is inertially referenced to ground. For the case of the shaft relative proximity probe, the dynamic vibration occurs about a –dc gap voltage, with the –dc gap voltage being proportional to the average distance from the probe tip to the target (shaft). These data plots display dynamic vibration data, but do not show changes in the average shaft radial position, an important response characteristic of the rotor syste
Vibration and Machinery Diagnostics
February 1 2011 -
Richard Thomas, P.E.
The root cause analysis of vibration problems related to critical turbomachinery is an engineering science based on what is often referred to as the "First Law of Machinery Diagnostics". The 1st Law states that displacement (vibration) is equal to the summation of the dynamic forces acting on the rotor divided by the complex dynamic support stiffness of the rotor bearing system.