What Type of Accelerometer Should I Use? IEPE, Charge or Bridge-based?

What type of accelerometer should I use? What are the advantages/disadvantages of a charge mode accelerometer, an IEPE accelerometer and a bridge based accelerometer?

There are so many types of accelerometer that is often difficult to know what type of accelerometer to use. An IEPE accelerometer will have a high pass filter at about 5Hz. The charge type will, by it’s nature have what is effectively a high pass filter at about 0.1Hz. Therefore neither type will show DC levels. The charge type will usually have a lower frequency bandwidth than the IEPE type. Charge accelerometers can be used at higher temperatures however. Continue reading What Type of Accelerometer Should I Use? IEPE, Charge or Bridge-based?

[Video] Create AVI files from your structural animations

The DATS Modal Analysis software consists of Hammer Impact Testing, Modal Analysis & Structural Animation (often referred to as Operational Deflection Shapes or ODS and Running Modes). Having measured and analysed your data the Structural Animation software allows you to visualisation your structure under certain operating conditions. These visualisations can then be saved as AVI files. This video shows you how…

Relative signal levels of a sinusoid with and without background noise

In the process of looking at some order data, a question about the accuracy of the measurement of the signal level of discrete frequency signals which were close to the general noise level.  To answer this question, a small DATS worksheet was created which generated 2 signals.  The first signal was a 35 Hz sinusoid which, by itself the spectrum level was measured to be approximately -9 dB (ref 1 V) as seen in Figure 1.

Spectrum level of 35Hz sinusoid
Fig 1: Spectrum level of 35Hz sinusoid

Continue reading Relative signal levels of a sinusoid with and without background noise

Creating calculated signals with DATS Acquisition

Case Study: What can I do if the transducer I am using has a non-linear sensitivity over its measuring range?

Abstract

Recently a PROSIG user wanted to measure a specific temperature parameter on a running engine. The transducer being used was one of the engine sensors built into the engine operating system to minimize engine emissions and maximize fuel economy. Unfortunately, the sensitivity of this transducer was not constant over the desired temperature range. The question then became, how can the output from this non-linear transducer be used to accurately measure the desired temperature parameter? Continue reading Creating calculated signals with DATS Acquisition

What sensors are required to perform a Rotor Runout Measurement?

The DATS Rotor Runout Measurement package can be used on any shaft where the following probes are available…

  1. A LVDT (Linear Variable Differential Transformer) probe. This is basically a contact probe. This will allow the measurement of the shaft total runout*.
  2. If an electrical runout measurement is also required then an additional eddy current probe (also known as a proximity probe) is needed. This is a non contact probe and can be used in conjunction with the LVDT to measure the electrical runout only.
  3. A once per revolution tachometer is also required. This could be optical, proximity, magnetic and so on.

With these three sensors it is possible using the DATS Rotor Runout Measurement package to find both electrical and mechanical runout.

* Total runout is a composite tolerance including the effects of cylindricity and concentricity, co-axiality, straightness and parallelism along the axis.