Main Reduction Gearing Lubrication and Condition Monitoring:
(a) Importance of Pre-Lubrication:
Supplying lubricating oil to the main reduction gearing before rotation is crucial for several reasons:
- Minimizing Friction and Wear: During initial startup, the metal surfaces of gears and bearings are in close contact. Without a lubricating oil film separating these surfaces, significant friction and wear can occur. Pre-lubrication ensures a protective oil film is present from the start, minimizing friction and wear during this critical period.
- Improved Gear Mesh: Oil acts as a slight wedge between gear teeth, promoting a more even load distribution and smoother gear mesh. Pre-lubrication ensures this oil film is present, allowing for smoother engagement and reduced gear tooth wear during the initial rotation.
- Heat Transfer: Gear operation generates heat due to friction. The lubricating oil plays a vital role in absorbing heat from the gears and bearings and transferring it to other components like the oil cooler (if present). Pre-lubrication ensures the oil is circulating and ready to effectively remove heat from the start, preventing overheating of the gears.
- Protection from Corrosion: Lubricating oil can also provide a layer of protection against corrosion on gear and bearing surfaces. Pre-lubrication ensures this protective layer is present before moisture or contaminants can come into contact with the metal surfaces.
In summary, pre-lubrication helps ensure smooth operation, minimizes wear, prevents overheating, and protects against corrosion during critical startup and initial rotation of the main reduction gearing.
(b) Condition Monitoring Techniques for Reduction Gearing:
Several condition monitoring techniques can be employed to assess the health and potential problems within the main reduction gearing:
- Oil Analysis: Regular oil analysis involves extracting a sample of lubricating oil and analyzing it for properties like viscosity, presence of wear debris (metal particles), and water contamination. Changes in these properties can indicate potential issues like gear wear, bearing wear, or water ingress into the system.
- Vibration Analysis: Monitoring vibrations of the reduction gearing using vibration sensors can reveal imbalances, misalignment, or gear tooth defects. By analyzing the frequency and amplitude of vibrations, potential problems can be identified before they cause major failures.
- Temperature Monitoring: Monitoring the operating temperature of the reduction gearing can indicate potential issues like overloading, lubrication problems, or excessive wear.
- Ultrasonic Inspection: In some cases, ultrasonic inspection techniques can be used to detect internal cracks or defects in gear teeth or bearings. This non-destructive testing method can help identify potential problems before they escalate.
- Borescope Inspection: A borescope, a small camera inserted into the gearbox, can be used to visually inspect gear teeth and bearings for signs of wear, pitting, or damage. This can be helpful in identifying specific problems within the gearing.
By implementing a combination of these condition monitoring techniques, engineers can gain valuable insights into the health of the main reduction gearing. This proactive approach allows for early detection of potential problems, enabling timely maintenance actions to be taken and preventing costly breakdowns.