Installation and Maintenance Manual: RLVAC
Published February 2022
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7. Install the bearings (48) and shaft fixing hardware on the new takeup pulley shaft, making sure
the pulley drum is centered between the bearings and that proper clearances of approximately
3/16” each side between the carriages and the takeup guides are observed. Torque the set
screws per ABB Motors MN3016 only after both bearings are fully installed and their mounting
bolts are torqued.
8. Check the chain (52) for proper tooth engagement on the sprockets (51).
9. Manually retract the tensioning cylinder until there is no slack left in the chain (52), to avoid shock
loading the takeup mechanism on first startup. Verify that both sides are taking tension evenly.
10. Replace any guards that were removed.
11. See section 5.12.2 for belt tensioning and tracking instructions.
6.6.4 Takeup Chain and Sprocket Replacement and Maintenance
1. Periodically (every 6 months or 2,000 hours of operation) clean and lubricate the takeup chain
(52) and connecting links (53) with an SAE 30 (ISO 100) gear and chain oil.
a. Brush the oil over the chain until every surface is wet (not dripping) with oil.
b. Soak up excess oil, as oil on the belt can cause it to slip.
2. The chain will need to be replaced if it has worn to a stretch of 1.5% or if the chain joints are
“frozen” or do not articulate smoothly.
a. Measure a distance of 20 chain pitches, center-to-center, with the chain under moderate
tension, to determine chain wear. A new chain will measure 12 1/2”, and a fully worn
chain will measure 12 11/16”. See Figure 26: Chain Pitch Measurement.
b. Both chains should be replaced at the same time, and the sprockets should generally be
replaced or rotated when the chains are replaced.
Figure 26: Chain Pitch Measurement
Rapid chain wear is a sign of insufficient lubrication! In very dusty environments or
areas with abrasive product contamination, the frequency of lubrication may need to be
increased.
3. Sprockets will need to be replaced or rotated once the sprocket teeth start wearing into a “hook”
profile with noticeable undercut. Both sprockets should be replaced or rotated at the same time,
but the chains need not be replaced if they are still in good condition.
4. To replace the takeup chains, remove the side guards on both sides of the takeup. See Figure
30: General Arrangement, Belt Under Roller AC, Pneumatic Takeup Drive, Sheet 1 of 1 for
details.
5. Ensure air pressure is removed from the tensioning cylinder (55) and the belt is slack. It may be
necessary to manually extend the tensioning cylinder to provide extra belt slack.
6. Remove the connecting links (53) from the takeup carriage and from the tensioning cylinder yoke.
7. Inspect the hanger bolts (64) in the tensioning cylinder yoke. Replace if they are worn or
damaged. Ensure both hanger bolts are adjusted to the same length away from the cylinder yoke.
8. Inspect the sprockets (51). If the sprocket teeth are worn, they should be replaced along with the
chain. Running new chain on worn-out sprockets will cause the new chain to wear faster.
