### accelerometers

How to avoid a ground loop – It’s not only a problem with accelerometers

## How to avoid a ground loop – It’s not only a problem with accelerometers

When using modern, high technology measurement devices one can often be tripped up by the simplest things. The most common is the ground loop. Time and again this issue rears its head. So, let’s talk about how to avoid a…

How Do I Calibrate An Impact Hammer?

## How Do I Calibrate An Impact Hammer?

The intention of this article is not to present any new scientific theories or ground breaking techniques, but to introduce new users to hammer impact testing and remind seasoned technicians of a method of how to calibrate an impact hammer and/or verify the…

What Is A Hammer Test Or Hammer Impact Test?

## What Is A Hammer Test Or Hammer Impact Test?

This is often also known as Modal Testing. It is a method of testing that allows us to calculate the natural frequencies (modes), modal masses, modal damping ratios and mode shapes of a test structure. This is commonly done using either…

Video: How To Calibrate Microphones & Accelerometers

## Video: How To Calibrate Microphones & Accelerometers

Here are two videos on a relatively simple, but sometimes misunderstood procedure – how to calibrate microphones & accelerometers

Vibration : Measure Acceleration, Velocity or Displacement?

## Vibration : Measure Acceleration, Velocity or Displacement?

When using vibration data, especially in conjunction with modelling systems, the measured data is often needed as an acceleration, as a velocity and as a displacement. Sometimes different analysis groups require the measured signals in a different form. Clearly, it is impractical to measure all three at once even if we could. Physically it is nigh on impossible to put three different types of transducer in the same place.

Which Should I Use? Real & imaginary? Or magnitude & phase?

## Which Should I Use? Real & imaginary? Or magnitude & phase?

In one of our recent articles a question was asked regarding the practical use of real & imaginary type plots compared with modulus & phase type plots. In general, noise or vibration signals are composed of one or more sinusoidal…

Using Your VCM To Monitor Auxiliary Equipment

## Using Your VCM To Monitor Auxiliary Equipment

The use of a vibration condition monitoring system for monitoring vibration from large rotating machines fitted with fluid-filled journal bearings such as steam or gas turbines is well understood. Vibration from these components generally falls within the main harmonics or…

Do You Need To Measure Brake Noise?

## Do You Need To Measure Brake Noise?

The objective of the brake noise tests was to record the braking events of cars being driven on various types of road and classify those events according to their type (Groan, Creep or Squeal etc) and severity. To do this…

A Simple Frequency Response Function

## A Simple Frequency Response Function

The following article will attempt to explain the basic theory of the frequency response function. This basic theory will then be used to calculate the frequency response function between two points on a structure using an accelerometer to measure the…

Acceleration, Velocity & Displacement Spectra – Omega Arithmetic

## Acceleration, Velocity & Displacement Spectra – Omega Arithmetic

Accelerometers are robust, simple to use and readily available transducers. Measuring velocity and displacement directly is not simple. In a laboratory test rig we could use one of the modern potentiometer or LVDT transducers to measure absolute displacement directly as static reference points are available. But on a moving vehicle this is not possible.

Measuring For Success With A Hammer Impact Test

## Measuring For Success With A Hammer Impact Test

The following application note shows the steps taken to perform a structural analysis using a hammer impact test on an automotive exhaust pipe structure with the aim of improving the structural damping properties of the exhaust pipe mount. This application…

In this note the different types of transducers that can be used with the Prosig P8000 series data acquisition system are discussed. The article deals with the design and function of the different types of transducer and the applications they…

A Simple Automotive Noise Test

## A Simple Automotive Noise Test

In a recent article we described how the Prosig P8000 hardware and DATS software had been used to help Dalmeny Racing diagnose a problem with an exhaust bracket on their Formula Ford racing car. Whilst the car was instrumented for…

Non Linear Calibration Curve And Polynomial

## Non Linear Calibration Curve And Polynomial

Not all systems vary linearly. One very well known case is, of course, thermocouples. International standard curves are available for these so they present little difficulty. The issue discussed here is determining a non linear calibration curve and if appropriate…

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