What is Angle- and Order- Analysis?
When analysing rotating machinery, one may use time or rotation as the reference. A time signal can be resampled from a fixed time resolution, dt, to a fixed angle resolution with the help of the tacho signal. This is what the tacho pulse looks like when resampled from the time domain to a fixed angle resolution (see Figure 1): Figure 1. A tachometer signal resampled from the time domain to the angle domain. One revolution is one square pulse period. The machine is speeding up, as can be seen in the square pulse width being shortened in the time record. (Click figure to enlarge) When...
read moreDIY Encoder for RPM and Torsion Vibration Analysis
Torsion vibration can be difficult to detect in rotating machinery as vibration occurs in a rotating component or drive train. Torsion vibration may result in equipment damage as loads increase and machine internal timing is affected. This post is about optic sensors and the use of a Do It Yourself (DIY) encoder to detect torsion vibration. A tacho signal can consist of one or more pulses per revolution. It can be picked up using e.g. a rotary encoder placed at a free shaft end, magnetic or optic sensors for the purpose of torsion analysis. Torsion analysis can be made using other...
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