IMPORTANT information for owners of industrial gearboxes

PLANNED gearbox maintenance can help prevent costly breakdowns

If you operate a system with a gearbox at its heart, you could be risking a costly breakdown if it has not been regularly inspected and maintained.

Listed below are some of the resulting causes of failure that can affect your older gear units that may not become apparent until the day the unit fails - usually with costly consequences.

Operating lives of rolling element bearings in auxiliary drives reduced due to oil contamination	Loss of auxiliary drive, damage to auxiliary components and possible secondary damage to main transmission gearing
High speed couplings become blocked	Accelerated wear due to lack of lubrication
Outer coupling system collects contaminant between the coupling teeth	Wear steps on gear teeth occur. If wear becomes greater than 0.020” or tooth surface deterioration results in loss of more than 50%, replacement components will be required.
Impurities gather inside planet spindles due to centrifugal forces	Sludge forms and prevents oil from reaching white metal bearing surfaces
Impurities which pass into the planet wheel	Surface scoring of planet wheel occurs and can cause breakdown of the white metal resulting in unit failure
Oil film breakdown due to water contamination	Breakdown of oil film between teeth of the running gear train giving rise to overstressing
Corrosion fatigue due to pitting condition	Possible corrosion attack and a reduction in endurance limit

Recommended maintenance procedures
Allen epicyclic gears - planned levels of maintenance

Noise & Vibration Survey

• Survey taken with gearbox running under
  normal operating conditions.

In-situ Remote Visual Inspection
(Borescope/Videoscope)

• Remove Gearcase inspection covers
• Inspect general appearance of components and any signs of rust
• Inspect gear teeth using Borescope/ Videoscope
• Check auxiliary drives
• Report.

Full Inspection

• Remove gear internals from gearcase
• Remove spindle end covers, inspect spindle bores, remove sludge deposits and clean thoroughly
• Dismantle gear completely, clean and inspect
  all components
• Check all oilways are clear
• Remove centrifuged sludge from high speed coupling sleeve, sunwheel and sunwheel coupling flange
• Dismantle trunnion mounts, check, clean and lubricate
• Check auxiliary drives
• Check Helicoil inserts and renew all locking plates and
  tab washers
• Check high and low speed alignments
• Report.

These recommendations are based on continuous running for units with auxiliary drives.
For low-use plant the time period between examinations may be increased, but not more than 50%, even though nominated running hours may not have been completed