Commisioning and Inspections
- Ensure that the steam is off the turbines and the turning gear is engaged.
- Wipe around inspection doors to prevent immediate dirt ingress
- Allow sufficient time for the gear case to cool before opening
- If inspection is non-routine, that is say due to an abnormality ensure extra time for cooling and open doors initially away from the area of concern
- Guard against items being dropped accidentally into gearcase
- Use only flame proof lighting
- Rotate main wheel at least one full turn
- Inspect all teeth for damage, record defects as appropriate. This normally takes the form of a sheet onto which a sketch showing the size and extent of damage (such as pitting) and a section fo added notes. These sheets are kept as a historic record of the gear allowing judgement on deterioration rate.
- Observe oil sprays and other internal fittings
- Look for rusting indicating faulty dehumidifier
Checking for mis-alignmentThis can be done by blueing one of the teeth then viewing the complimentary mating teeth. Where the blue has transferred this is where the teeth have meshed and this can be compared to the polished area of the on load contact areas.
If damage to the Bull wheel is suspected , say due to rapid decelleration of the propeller, and the Bull wheel may have slipped its shrink fit then alignment should be checked in a number of positions.
Operation and Maintenance
- A gear set will operate satisfactory provided;
- It is operating within limits
- It has sufficient high quality oil supply
- Close attention is paid to alignement during refits
- Flexible couplings are maintained
Excessive rust and sludge can lead to failure due to corrosion fatigue particularly in gears suffering from pittings
Blued tapes taken on inspection may be kept to record wear
IME recommends inspection periods no more frequent than 6 months to prevent undue contamination.