HGRS MASTER - Maintenance

Type of Skill: Specific Technical Skills

Category : Transport Equipment
Module: Belt conveyors
Unit: Belt Conveyor Troubleshooting 17 of 18
Version: 1.0 06-02-03
Reference: Belt conveyors MTC Training.ppt - Pages 62 to 66

Belt Conveyor Troubleshooting

Purpose:  To provide a summary of the more common problems, causes and solutions associated
with belt conveyor systems.

o While each conveyor and each transfer point is unique and individual, there
are a number of commonly encountered problems for which general causes
and possible cures can be prescribed.
o The techniques to ensure satisfactory belt tracking are mainly addressed by
the proper design of all belt conveyor components and appropriate
adjustment and maintenance

Refer table 1 belt training and table 2 belt damage

Standards:  Use of the troubleshooting guideline

Impact if not  High maintenance cost
correct:  Stoppages and improper operation

Actions:  Correct training and inspections

Unit  Use the guideline on a problematic conveyor belt

Completion:
See site specific unit for additional information, respective actions and applicable safety instructions

Training in Maintenance Page 1 of 7

Belt Training
Table 1
Problem Cause Cure
Belt runs true when empty, but Off-centre loading Adjust chute and other loading devices so load is delivered to
mistracks when loaded centre of belt in line with direction of belt travel

Fluctuations in load Use notched chute to keep load peak in centre of belt

Belt / idler contact not equal Adjust height of idlers for even contact

Conveyor belt runs to one side at a Idler(s) not at right angles to centre line of Move the end of the idler to which belt has moved in the direction of
particular point along conveyor belt the belt travel

Conveyor frame “crooked,” or idler Survey and align components

stand(s) not centred on frame

Loose idler or roller Secure idler or roller in proper position

Structure not level, belt climbs to high Align and level structure
side

Build-up of material on idlers Clean idlers; install effective belt cleaning and transfer point sealing
systems

One section of belt runs off to one Splice(s) not square Cut ends square and re-splice
side all along the conveyor
Belt edge worn or broken Repair belt edge; remove worn or out-of-square section and splice
in new section

Training in Maintenance Page 2 of 7

 Problem Cause Cure

Crooked or bowed belt If belt is new, it may correct itself when properly broken in.
Otherwise, replace with new belt or section

Conveyor belt runs to one side at Improper belt loading Change loading point and loading conditions so that load is centred
some distance along the conveyor properly
line

Belt has erratic action, following no Belt too stiff to train May be due to new belt, if so allow proper break-in time (It may
certain pattern shorten break-in time if belt is left loaded during downtime).
Use more troughable belt
Install self-aligning training idlers

Survey and align pulley and adjacent troughing idlers

Belt runs off at head Head pulley or troughing idlers leading to head
pulley out of alignment

Pulley lagging worn Replace worn lagging; use grooved lagging for wet conditions

Material accumulations on pulley face Clean up the fugitive material; install effective belt cleaning and
transfer point sealing systems

Build-up material on return idlers and/or Clean up the fugitive material; install effective belt cleaning and
Belt running off at tail pulley pulley transfer point sealing systems

Return rollers out of line Survey and align at right angle to frame

Unequal loading Adjust loading chute to properly centre the load

Control flow with feeder belts and deflectors to load material at
speed of belt

Counterweight too light Recalculate weight required and adjust counter-weight or screw-
take-up accordingly

Training in Maintenance Page 3 of 7

 Problem Cause Cure

Idlers frozen Clean and lubricate rollers. Install effective belt cleaning and
transfer point sealing systems to control fugitive material

Belt runs off on certain days Environmental conditions alter tracking Install windscreens and /or conveyor covers to reduce
exposure to elements. Install self-adjusting idlers

Belt Damage
Table 2
Problem Cause Cure

Excessive wear on bottom cover of Slippage between belt and drive pulley or Increase tension on belt take-up device
belt pulleys Lag drive pulleys, or renew worn-out lagging
Increase arc of contact on drive pulley with snub pulley or use
tandem drive

Sticking troughed idlers Clean and lubricate idlers to free rotation or replace
Install effective belt cleaning and transfer point sealing systems to
control fugitive material

Excessive troughed idler tilt Correct to not more than 20 from upright

Material grinding between pulley and belt Remove accumulated material. Install tail protection ploughs and
effective belt cleaning and transfer point sealing systems to control
fugitive material
Excessive impact of material on belt
Wear on top (carrying) side of belt Use correctly designed chutes and baffles, load fines first to
minimise impact level
Install impact cradles or impact idlers to absorb impact force
Excessive sag between idlers
Reduce idler spacing or install belt support rails/bars to maintain
sag-free belt line

Training in Maintenance Page 4 of 7

 Problem Cause Cure

Wear on top (carrying) side of belt Dirty, sticking, or misaligned return idlers Clean, repair, lubricate, and align return idlers. Install tail
protection ploughs and effective belt cleaning and transfer
point sealing systems to control fugitive material
Abrasive “pooling” action in loading area
Reduce chutes and feeder belts to feed load in same direction
Belt folding back on self
and at same speed as belt travel

Realign idlers to centre the belt. Remove obstruction causing

Material entrapped by skirting belt edge to fold back. Install misalignment limit switches to
Lengthways gouging or stripping of shut down power if belt wanders
top cover Space between belt and skirtboard not
increasing in direction of belt travel Metal sides of chute or skirts too close to belt
Skirtboard seal too stiff and pressed Adjust gap between skirt and belt to 10-18mm gap; gap
against belt
should increase in direction of travel
Belt spanks up and down on impact,
allowing material to become wedged into Use more pliable seals (620 Shore); avoid use of used belting
skirting as seal strip

Jamming of material in chute Install impact cradle, impact idlers, or troughed rails under
loading zone to maintain stable belt line

Belt mistracking and snagging on

Lengthways rips partially or entirely structure Widen chute and/or control size and volume of material
through belt
passing through chute
Puncture by tramp iron

Fastener failure Train belt

Accumulations of material
Use metal detector or magnetic remover

Improve splice or vulcanise

Remove accumulation, install cleaning devices, scrapers,

improve house-keeping
Training in Maintenance Page 5 of 7
 Problem Cause Cure

Star-shaped break or transverse Impact damage Use impact cradle below belt in loading zone to absorb
break in belt cover or carcass impact energy
Soft spots in cover or carcass,
ruptures, cracks, gouges, or general Material impingement between belt and Install tail protection plough to sweep material from return run
fabric decay pulley
of belt
Install decking or guards to prevent material falling onto return
run
Damage from exposure to abrasion,
chemicals, heat, mildew, oil, or Use belt designed for specific conditions
environmental conditions Avoid over-lubrication of idlers
Enclose belt line for protection from environmental conditions
Improper storage and handling of belt
Handle belt in accordance with manufacturer guidelines
Excessive wear on belt edges Improper loading, side loading
Control flow with feeders, chutes, and skirtboards
Belt stained on one side Feed should be in direction of belt travel in centre of conveyor

Allow time for new belt to break in

If belt is not new or does not break in properly, replace
Carcass or cover fatigue at idler Improper transition between troughed belt strained section
junction and terminal pulley
Increase transition length. Use transition idlers
Sever convex vertical curve Elevate terminal pulley

Decrease idler spacing in cure area. Use transition idlers

Excessive forward tilt of trough idlers Increase curve radius. Remove or lower any elevated idlers in
curve area
Excessive gap between idler rolls
Reduce forward tilt

Insufficient belt stiffness Replace with heavier belt. Replace idlers with new ones with
maximum gap of 10mm

Replace belt with stiffer belt

Training in Maintenance Page 6 of 7

 Problem Cause Cure

Transverse break in belt immediately Fastener plates too long for pulley size Change to smaller/shorter plates in mechanical splices or
behind mechanical splice increase pulley size
Fastener pull-out Improper fastener or improper installation
Review fastener selection and installation procedures
Excessive tension

Excessive tension
Separation at vulcanised splice Reduce belt tension. Consider “soft” or slower start up
Pulleys too small
Recalculate and adjust tension
Material between belt and pulleys
Use larger diameter pulleys

Use skirtboards properly, remove accumulation improve

Splice improperly performed
maintenance practice
Add decking and return run cleaning (tail protection) system

Re-do vulcanised splice

Training in Maintenance Page 7 of 7