Any gearbox is likely to undergo failure over time, yet with basic practices in preventive maintenance, breakdowns can be minimized. If your gearbox does fail, make sure the repair center you choose is qualified.
Below are four main problem areas with gearbox and maintenance techniques necessary for each.
A gearbox requires proper lubrication as oil prevents wearing down of the components while keeping them cool. Poor lubrication techniques are often linked with failures in gearboxes. With this in mind, it is important to check the oil levels regularly as too little amount of oil can result in damages on bearings and gears. On the other hand, excess oil increases operating temperatures, which may lead to the reduced life span of the seal and oil, as well as lower efficiency.With basic practices in preventive maintenance, gearbox breakdowns can be minimizedClick To Tweet
Most gearboxes are usually not supplied with oil, which means it is important that you consult your manufacturer’s recommendations when it comes to purchasing the right oil to use. Bearing and gear failures may arise with using the wrong type of oil or with poor viscosity. Keep in mind that with correct viscosity, the gear teeth are prevented from touching one another because of this thin protective film. Exposure of the gearbox to high temperatures can affect the viscosity, so be sure to change the lubricant when necessary.
When it comes to ambient temperatures that range from 50 to 125 ºF, the ISO 320-grade viscosity mineral oil may be used. So, with lower temperature during cold months, the oil becomes too viscous and less capable of lubricating. As for synthetic oils, these have a broader temperature range, yet there are compatibility issues that may arise with seals. So, it is always best to check recommendations by your manufacturer when selecting the right oil to use.
Make it a point to change gearbox oil regularly since grease and oil tend to break down in time. Once oil breaks down, its ability to maintain the right amount of oil film is reduced. Oil change also helps flush out any contaminants in the sump. So, it helps to establish an oil sampling program in the facility to monitor and improve the health and lifespan of the gearbox.
During inspection and maintenance checks on your gearbox, shaft seal areas must be inspected for leaks. The presence of leaks means the lubricant is contaminated, so seals with leaks must be replaced to prevent foreign particles from getting in. You should also clean or replace strainers or filters to eliminate contaminants in case there is a pressurized lubrication system in your gearbox. Debris stuck on filters because contaminated oil to go straight into the gears and bearings, which can minimize their life span.
Also, inspect the vents and keep them clean to prevent clogging. If there is a buildup of pressure in your gearbox, it may be from debris in the vents, which can progress to oil leakage and seal failure. You should also replace the saturated desiccant type of breathers. These components remove moisture from the air that may get into the gearbox. These become inefficient in performing this function when saturated.
It is important to maintain the right temperature of the equipment during operation to prevent overheating. Hence, a heat gun, along with other tools, may be used to measure and check the temperature. An overheated gearbox may cause oil degradation, wear on bearings, and gear and reduced seal lifespan.
Other tools used to measure temperature include RTDs, gauges, thermography and thermocouples. Upon monitoring the temperature, a baseline reading is established, and previous values must be analyzed and compared against subsequent readings. When there is an increase in temperature in the gearbox, or some localized hot spots are detected, this means the motor is not functioning efficiently. Although thermal data may not give complete information on the location of the problem, you can gain sufficient understanding that will lead you to further inspection of the gearbox.
Oil life is also improved by controlling the temperature. There is a limit of 200 ºF for oil sump temperature of gearboxes with ratings based on AGMA standards. Once the sum temperature goes beyond this value, R and O mineral oils degrade quickly, which shortens seal life due to wear on the bearing and gear. Synthetic oils may be suitable for operations that go above 225 ºF, yet the cost of this oil is higher than the price of mineral oil. Cooling packages may be used, as provided by manufacturers, such as an electric motor driven fans and heat exchangers to maintain the normal temperatures of gearboxes.
If there are abnormal sounds or noise while the motor is in operation, it is possible that the gearbox has some issues. Further increasing sound levels may be a sign of damages on the gears and bearings. A rattling sound, for instance, may be due to high vibration or loose fasteners. A knocking sound may mean broken bearings or teeth. As for squeals, these may be caused by metal rubs or loose bearings.
Lastly, you can perform vibration analysis to determine bearing or gear damage, along with coupling misalignment and improper foundation support. As with temperature analysis and measurements, you should study trends in vibration to understand any potential issues in the gearbox. This is why it is important to take a baseline reading while the gearbox is connected to the equipment being operated. These readings may be reviewed and evaluated by a professional analyst to help you determine existing or potential problems.
To maximize productivity and profits, you should improve the performance and lifespan of your motors in the facility. Hence, preventive maintenance practices must be implemented as these minimize downtime and premature damages on gearboxes that are essential to electrical machinery. By making an effort to perform these techniques, you can prolong the quality of your motors, make the workplace a safer environment, minimize operation costs and boost productivity with your motors’ optimum performance.