Excessive conveyor belt sag and poor troughing: causes and checks
A belt dropping between idler sets can spill material, increase flexing and accelerate wear. Check support, load and tension together.
Safety first: observe a running conveyor only from designated guarded positions. Isolate, lock out and verify zero energy, and secure take-up movement, before any hands-on check or correction.
Symptom
Observe sag between idler sets, spillage near transitions or secondary mistracking under load from a guarded position.
Evidence
Record loading, idler spacing, failed rolls, support deflection and take-up position. Compare them with the approved conveyor design.
Causes
Excessive idler spacing, inadequate tension, flexible loading-zone support, seized idlers or sustained overload can contribute. Do not assume low tension is the only cause.
Verification
Check actual load and tension against design values and confirm idler spacing and support stiffness. Assess troughability and transition geometry with the belt supplier.
Action
Isolate before replacement or adjustment. Restore failed support, correct overload and set tension only within approved limits; over-tensioning can damage the belt and drive.
Related Catenary calculators
Related standards on MechAtlas (status and edition)
Source note: Belt Conveyor.pdf, p. 17. Field guidance supports your judgment. Site procedures, manufacturer instructions and current standards govern final decisions.