Richard Thomas

Richard Thomas has 35 years of rotating equipment experience in industry and currently holds the position of Global Services Manager for Metrix Instrument Company. Prior to his current position, his work experience included 11 years as a rotating equipment engineer in the petrochemical industry; 17 years in the Engineering Services Department of Bently Nevada Corporation; and 6 years as the Global Services Manager for RoMaDyn Corporation.

Second Order Kalman Filter for Vibration Monitoring


Should I Install Single Plane or XY Proximity Probes?

Richard Thomas, P.E.

Dissipating Rotor Vibration Energy via a Fluid Film Bearing

Richard Thomas, P.E.

The following statement is often referred to as the “1st Law of Machinery Diagnostics”:

Vibration Displacement (Vector Quantity) =

Summation of Forces Acting on the Rotor System (Vector Quantity) divided by the System Dynamic Stiffness (Vector Quantity)

Shaft Average Centerline and DC Data Plots

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

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.


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