Change Tension (if essential): When the tension is just not in just the required variety, modify the belt tensioner or exchange the belt as wanted. Measuring basic principle: Frequency measurement by LED light even though the belt isn't transferring. The belt is toughed by hand to produce vibration. The Motor https://emilioluboq.wssblogs.com/32439389/the-smart-trick-of-belt-tension-gauge-tool-that-no-one-is-discussing