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. Contine reading

Calibrating an Accelerometer with a Prosig P5000 system

Here we look at how to calibrate an accelerometer using a Prosig P5000 system.

Put the wax on the shaker top. Place the accelerometer in the axis you wish to calibrate with positive up and cable connected to P5000 with the relevant transducer class chosen.

Accelerometer calibration screen

Accelerometer calibration screen

Go to Single Channel Calibration screen.

Click on the Tone tab.

With P5000 armed turn on the shaker and monitor the sine wave on the real-time monitor and check Signal Quality as being GOOD.

With a GOOD sine wave click the Calculate button. It is recommended to click Calculate three times.

Check to see the Sensitivity change from what was originally entered when setting up the channel transducer information to the new calculated value. The calculated value should be close to the original.

DC Cal Offset is for DC level accelerometers.

Requested Excitation is for non IEPE (ICP) accelerometers such as capacitive.

After calculating the new sensitivity click on the Use button to make the change in the Transducer Sensitivity Acquisition Setup file.

NOTE: To achieve a GOOD signal reading place the shaker on a flat surface and avoid touching during operation. Make sure the surface the shaker is sitting on does not come in contact with other sources of vibrations or electrical conductance.

How do I balance a shaft?

“How do I balance a shaft?” seems like a fairly straightforward question, but there are a number of things that we need to understand first. Here we look at a number of key concepts that need to be understood in order perform balancing.

What does balance mean?

Well broadly speaking to balance a shaft, mass must be added or removed at certain angles. The concept being that the centre of gravity and rotational centre of the shaft will be equal when the shaft is balanced. Contine reading

How Do I Get An XYZ Resultant Waterfall

A user has three signals captured using a triaxial accelerometer and asked “What is the simplest way to get the XYZ resultant from run-up file?” He had tried forming a resultant of the raw time histories, but didn’t fully understand the resultant time history.

Of course, the correct way of processing the data is to calculate the individual waterfalls from the x, y & z data and then calculate a resultant waterfall. Contine reading