Keeping good care of your gearboxes is key to the longevity of your unit’s life. The gearbox is just as important as the engine in power generation. The engine creates the power – the gearbox transfers the power. Let’s review a few general maintenance and oil analysis best practices to ensure your gearboxes stay healthy.
General Maintenance
Before we go into laboratory testing, there are a few things you can do directly in the field to monitor and maintain the condition of your gearbox:
- Reduce contamination: There should never be any open ports on your gearbox casing. Anything airborne will go directly into your tank reservoir and subsequently into your equipment. If your gearbox is located outside, any windy, dusty days could cause excess contamination. Likewise, in humid locations, water contamination can become an issue. Reduce the possibility of contamination by installing desiccant breathers to open ports. This will help reduce humidity and airborne contaminants. Water contamination can also occur from careless oil dispensing. Always use clean and water free containers for adding oil. It is more expensive to clean the oil after it is contaminated then to just keep it clean in the first place.
- Visual inspection of oil condition through inspection ports: Watch for any abnormal color changes such as the oil darkening, the oil turning milky or creamy, and foaming.
- Monitor for overheating: There are a few visual cues that can help you identify if your gearbox is overheating such as smoke coming from your shafts, burnt casings, any melted plastic pieces on the casing, and if water evaporates quickly if splashed. Other cues more related to the oil itself are darkening of the oil and foam. Other items to inspect are oil level and filters for any visible metal flakes.
Oil Analysis Best Practices
For gearboxes there are three main lab tests which you should include in your oil analysis program.
- OPC ISO particle count: This test indicates the level of contamination by giving you an ISO particle count but also a visualization with particle shape recognition technology. The technology scans for different wear modes and categorizes them so you can see what general wear trends are happening on the inside of your machinery.
- Water (by Crackle or Karl Fischer): Measuring if you have water, and the amount of water, is critical in gearbox upkeep. Water accelerates oxidation and promotes corrosion, two things that can cause critical failures on your gear boxes.
- Acid number: Acid is a byproduct of the oxidation process and this test measures the number of acidic substances in the oil. By measuring acid number, you can better optimize your oil change intervals to reduce the chance of varnish.
Our Plant 2 package specifically looks at these parameters as contamination may be responsible for up to 70-85% of all lubricant related failures. In addition to oil sampling, inspect your oil filters and magnetic plugs regularly. Monitor for potential contamination issues by sending your filter for analysis (SEM or Analytical Ferrography). Magnetic plug condition can be tracked as well in myLab through the photo upload feature and contamination particles assessed through SEM-EDS or Analytical Ferrography analysis.
Where to Sample
With gearboxes you should try and be as consistent as possible in your sampling. Drain valves are a good start, a drain port with a pitot tube is better, and the best practice would be to use a high pressure port adaptor (assuming your gearbox has a circulating lube oil system or able to be filtered through a portable filter cart).
A rule of thumb for filtered systems is if you are taking a sample before a filter the state of the GEARBOX is prioritized. If the sample is taken after the filter the state of the OIL is prioritized. Be sure to utilize your oil analysis data to the fullest to be calculative with your maintenance on your gearboxes.
Key Takeaways
- Do not have any unprotected openings into the tank. Anything in the air will get into the tank and ultimately your system. Be sure to add breathers or keep open ports closed off. You can monitor contamination with OPC ISO particle count. Reduction in contaminants will extend the life on your components.
- Monitor and keep out water from your system. The only way water is getting in is if we allow it to get in!
- Acid levels are controllable- keep an eye on them before they become a problem.
- Sample location and consistency is key.
- Greater risk of failure comes after disassembly as human error becomes a contributing factor. Be sure to utilize your oil analysis data before you do any major work on your gearboxes to determine that the work is required.
Contact us to learn more about oil analysis for gearboxes.