How to Lubricate Your Gearbox for Seasonal Temperature Changes
Many people incorrectly assume that high running temperatures created by friction within the gearbox are the only temperature fluctuations that can adversely affect its performance, but the truth is that changes in outdoor temperatures can also negatively influence the operation of industrial gearboxes. As a matter of fact, extreme weather scenarios can impact the performance of gearbox lubricants and lead to gearbox failure. To avoid seasonal issues, it’s important to understand the effect that outdoor temperatures can have on gearbox oil and how adjusting lubrication during outdoor temperature changes can prevent weather-related downtime.
What’s in Your Gearbox
Gearboxes are an essential component used in many industrial machines to change torque, speed, and direction/vector of rotary motion. A gearbox consists of an enclosed series of gears, shafts, and bearings that transmit power from a motor within industrial machinery. Proper lubrication is necessary for the gearbox to function at its best and to prevent catastrophic damage to the contained gears and bearings. Not only does lubrication protect metal parts from corrosion and prevent wear and tear, it also serves as a coolant to combat heat caused by friction inside the bearings and between the gears during normal operation.
How Temperature Affects Oil Viscosity
Without proper lubrication, a gearbox will not perform efficiently and will eventually overheat and fail. A maintenance schedule that includes lubrication is an obvious priority, but many technicians don’t realize that extreme outdoor temperature variations can change the viscosity of the lubricant and the way that it moves through the system. This can be a critical error if your facility is located in an area that experiences severe seasonal temperature swings. (We’re looking at you, Northern U.S. and Canada.)
During the hot summer months, oils will be thinner and the gears and bearing elements will not ‘hydroplane’ on one another as easily, so there will be more sliding/rolling friction and wear. During the frigid days of winter, oils will be thicker and more difficult for the gears and bearing elements to mix around so there will be more fluid friction and uneven lubrication. Either scenario can lead to gearbox failure.
So, if your facility is in an area that experiences radical temperature changes between seasons, it might be necessary to use different grades of oil at different times of year and/or develop remedies for more efficient lubrication of components to avoid damaging equipment. Several oil characteristics must be considered when selecting lubricants for temperature changes. One of the most important characteristics is the temperature index. Some formulations will have a flatter temperature index than others, which means that as temperature increases, viscosity will decrease at a slower rate. For example, most synthetic oils have a flatter temperature index than mineral-based oils, so even at lower temperatures, synthetic oils will be less viscous than mineral-based oils. The pour point of the oil, the lowest temperature at which oil will flow when chilled, and the low-temperature operating limit of the oil are other important characteristics to consider.
Knowing the technical characteristics of your lubricant and being aware of the climatic factors that surround your facility can help determine whether a seasonal change in lubrication is necessary and, if so, what lubricant will work best during winter and summer months and when the changeover should take place. Usually, it is advised to switch lubricants prior to the seasonal change to ensure that the proper lubricant is already flowing through the system before the temperatures heat up or cool down.
Additional Measures May Be Necessary
It’s also important to know that extreme temperature swings may necessitate the use of an oil heater or an oil cooler. When cold weather hits, it may be necessary to take additional steps to prevent failure of the lubricant and the gearbox it serves. Some suggestions include insulating or applying heating blankets or heat tracing to lubricant containers or using a space heater in the area. Lubricant piping may need to be insulated or traced with heat tape, as well.
Gearboxes may also be equipped with case heaters that, can be turned on when extreme cold is expected, to keep lubricant flowing at its proper viscosity. The addition of circulation pumps may also be needed during cold-weather idle times to continuously circulate the oil through the equipment.
Clearly, gearbox lubrication is not one-size-fits-all in areas where there are drastic seasonal temperature variations. Because changing outdoor temperatures can affect the way that oils behave in a gearbox, it’s essential to select a lubricant with the right temperature characteristics for your area in the summer and winter and to ensure that the changeover takes place prior to extreme temperatures. This will help keep your gearbox properly lubricated and prevent it from overheating at any time of year, thus maximizing its service life and efficiency while minimizing downtime.
For more information on seasonal gearbox preparations, please contact a specialist at John Henry Foster.