Top treating is the practice of adding new additives to existing oil. Once condition monitoring detects a depletion of additives, operators can replenish them using an aftermarket package. This has the advantage of delaying a flush and refill of the gearbox oil, but it can lead to complications. What’s more, the need for top treating can be avoided by using a balanced lubrication strategy from the start.
Equipment reliability is critical to the economic success of wind turbines. Unscheduled downtime leads to lost energy generation and the need for maintenance, which can be potentially hazardous, especially for offshore windfarms. A good lubrication strategy is therefore critical to ensuring optimal reliability.
Top treating is often used to mitigate the depletion of oil additives, but it can also potentially make the oil unbalanced and hinder performance. This is because additives must compete for space on a metal’s surface. For example, if after top treating an oil contains far more anti-wear additives than anti-rust ones, the gears may experience more rusting than they normally would. If top treating disturbs the subtle balance, it can potentially do more harm than good.
In addition, although top treating is less resource-consuming than an oil change, it will, at the very least, involve a technician climbing hundreds of feet up a tower. Every such trip incurs an element of risk, so occurrences should be minimised whenever possible.
If top treating isn’t such a good idea, what is the alternative other than a full change? The solution is surprising simple – use a balanced oil formulation from the start. By using an oil formulated using the right balance of advanced base oils and additives, wind turbines operators may find it still protecting their equipment after 60,000 hours of service.
For example, ExxonMobil, which also makes industrial lubricants like Mobile DTE Light, offers a limited seven-year guarantee with Mobil SH Gear 320 WT, which is currently its most advanced product for wind turbines. The company claims this oil can also deliver exceptional protection even in extreme conditions.
While advanced lubricants come at a premium over conventional ones, selecting the right lubricants can deliver costs savings in the long run. The longer you can count on a lubricant staying effective, the less need there is for monitoring and intervention. This avoids the risk of unbalancing the lubrication through top treating and reduces the need for your staff to make potentially dangerous trips up towers.