## Rotating Machinery Test Rig

A long-standing customer brought along his power station turbine test rig so that we could give the P8000 hardware and DATS software a good workout. Here’s a video of the rig in action. Watch this space for some data and…

## Three Methods For Analyzing Vibration In Rotating Components

In this post we will first look at how to process data from rotating machinery. Then we will focus on shaft or gear train twist. Let’s look at 3 different ways to measure and analyse rotating shafts. Each one has…

## A Method Of Diagnosing Cyclic Events In An Internal Combustion Engine

A method to identify subjectively objectionable disturbances (e.g. piston slap, valve tick,… etc) in internal combustion engines

## Generating speed v time information from noise & vibration signals

Picture the scenario; you have captured some noise & vibration data from a rotating machine. Typically, this might be noise in a vehicle cabin, but could have been anything from a tiny pump to a full size power station turbine.…

## Understanding Phase Measurements

When performing frequency analysis of vibration data for any application the resultant spectrum has both amplitude and phase components, therefore the phase component represents half of the information available and can provide a valuable insight into the causes of the…

## What Is Resonance? (Part 3)

In the previous two articles (What Is Resonance? (Part 1) & What Is Resonance (Part 2)) in this series we have looked at how we can identify a resonant frequency. Now we will discuss what happens next. What do we…

## Waterfall Analysis: Frequency Spectrum or Order Spectrum?

This article addresses two basic approaches to analyzing rotating machinery during transient (sweeping rpm) conditions.  The first is the traditional method which uses Frequency (FFT) Spectrum analysis at target rpm values throughout a run up or a coast down condition.…

## Building a new test model

Recently, we decided it was about time we had a new model for testing, training and demonstrations. Specifically, we wanted something that would allow us to test the full capability of the standard tacho channels available on the P8000 systems…

## Waterfall Analysis: Frequency Resolution and Smearing

When measuring noise and vibration in rotating machines, especially complex devices like automobile engines, it is very important to fully understand what is being measured and what analyses need to be performed on the resulting data. Even the most sophisticated…

## Video: Noise & Vibration From Rotating Machines

This is complete version of the video illustrating my recent article How To Measure Noise & Vibration In Rotating Machines. This video was previously published on the blog in 3 parts. The video will be best enjoyed by selecting the 720p…

## How To Analyze Noise & Vibration In Rotating Machines

In this article we will look at the basic steps needed to measure noise & vibration in rotating machines. We won’t look in great detail at some of the techniques involved – we deal with these elsewhere on the blog. This material…

## Do Missing Tachometer Pulses Mean The End Of The Road For Your Test?

Creating a good quality tachometer signal is one of the hardest parts of analyzing rotating machinery. So what happens if we have missing tachometer pulses? The data looked great until we tried to perform some in-depth torsional vibration analysis. And…

## PROTOR Vibration Condition Monitoring System Installed in Three Thermal Power Plants in Spain for Iberdrola

IBERDROLA has launched a renewal plan for the existing condition monitoring systems in their plants in Spain. This plan will be implemented gradually and PROSIG was selected to install their PROTOR Vibration Condition Monitoring System in three IBERDROLA power stations.…

## Aliasing, Orders and Wagon Wheels

These days most people collecting engineering and scientific data digitally have heard of and know of the implications of the sample rate and the highest observable frequency in order to avoid aliasing. For those people who are perhaps unfamiliar with…

## Vibration Condition Monitoring Using Your Android Smartphone

Ever been lying on the beach and begun to wonder about the state of your LP turbines? Or out on business and anxious to know if that troublesome exciter bearing has settled down? Well with a Prosig PROTOR system and…

## How To Analyze & Measure Torsional Vibration

Knowing how to measure torsional vibration is of key importance in the area of vehicle development and refinement. The main contributory source is the engine where periodically occurring combustion cycles cause variation in the crankshaft rotary vibration. This vibration is…

## Shaft Displacement Measurement Using A PROTOR System

Shaft displacement is an important vibration measurement for rotating machines. Shaft displacement is usually monitored by non-contact shaft displacement probes such as eddy-current probes. These probes produce a voltage proportional to the distance of the shaft surface relative to the…

## Vibration Monitoring Phase Measurement And The Tacho Signal

Any vibration signal may be analyzed into amplitude and phase as a function of frequency. The phase represents fifty percent of the information so it is most important to measure phase for vibration monitoring. Most vibrations on a rotating machine…

## Orders v Time – Comparing Overall Levels

By combining a speed signal with a data signal and using the Short Time FFT algorithm (Hopping FFT), it is possible to extract order data directly as a function of time (Orders from Hopping FFT) rather than as a function…

## Measuring Torsional Crank Shaft Jitter

Using Prosig’s P8000 series data acquisition system with DATS signal analysis software, torsional analysis (crank shaft jitter) was performed on an automotive engine attached to an engine dynamometer. The significance of this is that only one tachometer channel was required…

## Updated Protor System For Ringhals, Sweden

Prosig installed a PROTOR system at the Ringhals1 reactor in Sweden in 1992. This system was based on the PROTOR2 level of hardware and software and consisted of a Sun workstation and PC based acquisition system. The system has been…

## Torsional Vibration, Tacho Pulses And Aliasing

With shafts, gears and the like, the general method of determining the rotational speed is to use some form of tachometer or shaft encoder. These give out a pulse at regular angular intervals. It we have N pulses per rev…

## Analyzing Shaft Twist And Repairing Damaged Tachos

A shaft has been instrumented with two shaft encoders, one at each end. Each shaft encoder gives out a once/rev pulse and a 720 pulses/rev signal. Each signal was digitised at 500,000 samples/second. The objective is to measure the twist…

## Phase Angle Between Signals

The following article was written in response to a question from a visitor to the website. The gentleman in question had been reading some of the Prosig signal processing articles and had the following question. Dear Sir, It was interesting…

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