TL;DR
Drive pulley slippage is caused by insufficient belt tension or worn pulley lagging. Check takeup tension first before replacing lagging.
What you might see
- drive motor current spikes on start
- burning rubber smell at head pulley
- belt speed below setpoint under load
- belt surface scuffing at drive pulley
Likely causes
Takeup counterweight set too low giving insufficient belt tension at the drive pulley
Drive pulley lagging worn smooth, reducing the friction coefficient
Belt surface contaminated with water or oil reducing traction
Overloaded conveyor exceeding drive capacity at startup
Required tools
- Tension measurement gauge or hydraulic pressure gauge
- Cleaning rags and appropriate solvent
- LOTO kit
Safety first
- Lock out drive before touching the belt or pulley surface.
- Counterweight takeup systems on large conveyors use very heavy weights. Keep clear of the takeup travel zone.
Procedure
- 1
Stop the conveyor and lock out the drive.
- 2
Measure the takeup tension by reading the counterweight position or hydraulic takeup pressure against the design value.[1]
- 3
If tension is below the specified minimum, adjust the counterweight or increase the hydraulic takeup pressure to the design value.
- 4
Inspect the drive pulley lagging surface. Lagging worn smooth or showing deep groove tracks needs replacement.[1]
- 5
Clean the drive pulley and belt contact surface of any oil, mud, or mineral fines contamination.
- 6
After adjustment, restart under no load and slowly increase feed rate while monitoring motor current for slipping behavior.
- 7
If slippage persists at correct tension, arrange a drive pulley lagging replacement during the next planned outage.
Sources
FLSmidth FLSmidth pipe conveyor Heavy-Duty Conveyor (Mining) general technical documentation, FLSmidth
FLSmidth conveyor service documentation, belt tension and lagging inspection procedures (general)
More guides for FLSmidth FLSmidth pipe conveyor
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A belt rotation fault is most often idler misalignment or a blocked idler causing the pipe to open. Walk the belt and identify the first misaligned idler cluster, then realign.
How to identify and replace failed idler bearings on a FLSmidth pipe conveyor
Scan the idler clusters with an IR thermometer during a run. Rollers above 70 degC have failing bearings. Mark and replace them during the next brief stop.
Stop fixing the same fault twice.
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