A conveyor counterweight take-up must apply the calculated belt tension while remaining free to travel as the belt stretches and operating load changes. If the carriage sticks, reaches a travel limit, or carries the wrong effective weight, the conveyor can develop drive slip, excess sag, poor tracking or excessive belt/splice stress. Diagnose travel first: record the carriage position, confirm guides and sheaves move freely, inspect rope/chain and buildup, then verify counterweight against the conveyor design and check whether belt elongation or a splice change has consumed the available travel.
Restore correct belt tension and usable take-up travel without overloading the belt, splice, pulleys or bearings.
Use carriage position/travel, counterweight mass/design, belt slip or sag, rope/sheave condition, guide freedom, belt elongation, splice history and load.
Free mechanical travel and restore design geometry first; recalculate tension before changing counterweight mass.
Record take-up position before changing tension
Capture: carriage position within total travel; whether it is at/near an end stop; counterweight arrangement and any recent added/removed mass; belt sag at representative locations; drive slip history; belt and splice age; any recent re-splice or belt replacement; sheave/rope condition; buildup around guides; and load conditions when the problem occurs.
Counterweights and suspended take-up components store substantial potential energy. Follow the conveyor’s lockout, blocking and restraint procedure before entering the take-up area.
1. Verify that the take-up carriage is free to move
Inspect guides, rails, wheels or slide surfaces for corrosion, distortion and material buildup. Check whether the carriage is cocked in its guides or physically contacting structure. A stuck carriage can make a correctly sized counterweight ineffective because the belt no longer receives the intended tension adjustment. Clean and repair the mechanical path before changing weight.
2. Inspect ropes, chains, sheaves and bearings
Where the take-up uses wire rope or reeving, inspect rope condition, grooves, sheave rotation, bearings and alignment. A seized sheave changes the force transmitted to the belt and can damage the rope. Look for uneven groove wear, rubbing, broken strands and misrouting after maintenance. Replace components to the take-up supplier’s criteria.
3. Check remaining travel against belt elongation
Belts stretch during run-in and over service life. A counterweight carriage initially installed too close to one end can run out of travel even when counterweight mass is correct. Review belt length/splice history and compare present carriage position with the design installation position. If travel is exhausted, the belt may require re-splicing/shortening or another engineered correction rather than more weight.
4. Verify counterweight mass from calculations, not by trial
The required tension depends on conveyor geometry, drive, load and take-up location. Too little effective weight can permit drive slip and excessive sag. Too much can increase belt, splice, pulley and bearing loads. Use the original conveyor calculation or an updated engineering calculation after modifications. Do not add scrap steel because the belt slipped once; first inspect lagging, wrap, contamination and abnormal resistance.
5. Check belt sag and return/carry idlers
Excess sag between idlers can indicate insufficient tension, but stuck idlers, spillage and loading problems also increase resistance and change belt behavior. Inspect representative carrying and return idlers, especially near loading and drive areas. If the counterweight position looks normal but the belt still sags abnormally, confirm the belt is not operating beyond its design load or with damaged support components.
6. Correlate take-up condition with drive-pulley traction
Drive slip can be caused by insufficient tension, but worn lagging, water, cement dust, low wrap or excessive conveyor resistance can produce the same symptom. Inspect the drive pulley and compare motor current. If slip happens with high current and a correctly positioned take-up, investigate load/resistance and traction before increasing counterweight.
7. Check tracking after restoring take-up movement
A jammed or skewed take-up pulley can steer the belt and create mistracking. After mechanical repair, verify the take-up pulley remains square to the conveyor centerline through its travel. Tracking adjustments should be made only after the take-up, loading and structural alignment are mechanically sound.
Take-up diagnostic matrix
| Evidence pattern | Likely direction | Next check |
|---|---|---|
| Carriage at end of travel | Belt elongation/initial position issue | Belt length, splice history and design travel |
| Carriage position fixed despite load changes | Mechanical sticking | Guides, buildup, wheels/slides, sheaves and rope |
| Belt slips with counterweight in normal range | Traction/resistance problem | Lagging, contamination, wrap, idlers, plugged chute |
| Excessive sag with light counterweight | Insufficient calculated tension | Recalculate and verify conveyor loading |
| Belt/splice stress high after weight was added | Excessive tension | Restore calculated weight and solve original slip cause |
Common mistakes
- Adding counterweight before checking whether the carriage is stuck.
- Running with the carriage against an end stop.
- Ignoring seized sheaves and damaged rope.
- Using counterweight to compensate for worn drive-pulley lagging.
- Adjusting tracking before squaring the take-up pulley and guides.
Return-to-service verification
After repair, verify the carriage moves freely through the available travel and remains clear of stops at the normal operating condition. Run the conveyor empty and loaded according to site procedure. Acceptance means no drive slip, acceptable belt sag, stable tracking, smooth take-up movement, normal motor current and no abnormal rope/sheave or pulley motion. Record the final carriage position as a baseline so future elongation can be trended.
Related Infinity technical guides
References
Conveyor troubleshooting guidance identifies insufficient counterweight, improper initial carriage position, restricted take-up travel and mechanical sticking as causes of slip, sag and apparent belt stretch. Counterweight mass and minimum travel must be based on the specific conveyor/belt calculation rather than generic values.