Belt/Chain drives

               Belt slippage – will lead to rapid wear and premature failure. The common causes of belt slippage are insufficient tension, drive overload and the presence of oil or grease on the belt.

               Belt squeal – squealing often accompanies belt slippage and can be caused by overload, under tensioning and insufficient arc of contact.

               Belt ticking or slapping  - this may be caused by some form of mechanical interference – possibly from a poorly fitted guard or machine part.

   Belts break – may be due to overloading in the form of shock loads or heavy starting loads, by being damaged by prizing over pulleys. Contact with foreign objects may also damage the belt.

               Belt whipping – belt whip can cause the belts to jump out of the pulley grooves or to roll over and become damaged. May be caused by too long a centre distance, pulleys not running true on their shafts and pulsating loads.

Belts turn over – lack of tension, cords may have broken in the belts through being damaged on fitting. Pulsating loads and belt whip, the effect is to damage the belts which must be replaced. A spring loaded jockey pulley may help to prevent this condition from occurring.

               Wear – a well fitted belt will eventually wear and indicate even wear on the belt flanks. If the drive has been in misalignment, uneven flank wear will result, leading to premature failure. Another cause of rapid wear may be due to dust or abrasive particles being trapped between the pulley grooves and the belt.

               Cracking – cracking on the underside of the belt may be caused by excessive heat build-up which eventually causes the material to harden and become brittle. Chemical fumes may also contribute to this condition as will under tensioning. Too small diameter of jockey pulley will also cause this effect.

               Fraying – fraying along the edges of the belt usually indicates that some mechanical interference is the cause or that the pulleys are badly worn or damaged, exposing sharp or abrasive edges.

               Stretching – if a belt has been adjusted up to its maximum allowance on the installation, then either it has reached its natural fatigue life or the cords may have broken.

               Swelling – swelling or softening may be caused by excessive contamination by oil, cutting fluids, rubber solvent or other chemicals.

               Burns – usually, burns are due to rapid overheating due to a jammed driven shaft, where the belt has repeatedly been slipping or by initial slippage at start-up.