Stroboscope

Commissioning Air Systems (BG 49/2015), written by Chris Parsloe and published by BSRIA in March 2015, explains how to commission ducted air distribution systems in buildings. It was originally published in 2013 and was then updated in 2015.

It states: ‘The stroboscope is a source of variable frequency light pulses and its technique is to match the source pulse frequency to the rotational speed. A chalk mark (or similar) is made on the pulley and the stroboscope is adjusted until the mark appears stationary. It is, however, possible to obtain a stationary image with a sub-multiple (50%, 25% and 33% etc.) of the actual shaft speed and such errors of harmonics need to be eliminated to assess the correct speed. A convenient method is to start at high speeds where multiple images are obtained. Due to this inherent problem and the need for experience in its use, the stroboscope is only recommended when it is impossible to use one of the other rotational speed measurement instruments.’

--BSRIA

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