Rotational Analysis with no Tachometer Data
The identification of cyclic events in rotational analysis is often key to identifying problems. It is good practice to use a suitable sensor for capturing rotational speed. However, this is…
titanium and steel gears and cogwheels
Analysis of Dynamic Engine Vibration – Angular Vibration in High Performance Engines
The analysis of dynamic engine vibration and the accurate measurement of angular vibration is a non-trivial task, as a more in-depth analysis of boundary conditions reveals. Tools for engine vibration…
Vehicle AC
Analysis of Airflow Instabilities in HVAC units
HVAC (Heat Ventilation Air Conditioning) units are devices used in various applications, such as cars, buildings, aircraft etc. They facilitate the transport and conditioning (heating, cooling, changing of humidity) of…
The Effect of the Nyquist Theory on Rotational Order Analysis
Nyquist theory is generally understood, but this understanding usually relates to time sampling and the conversion to the frequency domain. Rotational order analysis and the effect of the Nyquist frequency…
A Guide To Digital Filtering
Understanding filters is actually simpler than it may first seem. Creating a filter is another story; it’s like being able to drive a car without having to know the intricate…
How To Choose A Sample Rate For A Required Analysis Frequency Range
The relationship between sample rate and maximum frequency that can be analysed (called bandwidth) is a factor of 0.4. Or to look at it another way the sampling rate is…
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…
How Do I Downsample Data?
Sometimes we have digitised data at a much higher rate than we need. How can we downsample data? If I wanted to say halve the sample rate can I just throw away every other data point?
The answer is NO, except in pathological conditions where you know that there is no frequency content above the new Nyquist frequency.
