Oil-filled drum motors generally use an internal oil cooling and lubrication system. The oil lubricates gears, bearings, and other transmission components while also helping transfer heat generated during motor operation. The choice of lubricant therefore affects component wear, motor cooling, and overall operating stability.
No. 150 synthetic extreme-pressure industrial gear oil is suitable for some oil-cooled drum motors, but it is not a universal specification for every model. The correct lubricant depends on the drum motor design, manufacturer's requirements, operating temperature, and load conditions.
Select the lubricant according to the drum motor model
The first step in selecting oil for an oil-filled drum motor is to confirm the lubricant type and viscosity grade specified by the manufacturer.
For example, some TJ-series direct oil-cooled drum motors recommend No. 150 synthetic extreme-pressure industrial gear oil. This lubricant is intended to meet the requirements of the internal gear transmission system in terms of lubrication and load-carrying capacity.
Different brands and drum motor models may require different lubrication specifications. Some products use ISO VG 68, ISO VG 150, or ISO VG 220 lubricants. Other options include mineral oils, synthetic oils, food-grade lubricants, and oils formulated for low-temperature applications.
Therefore, No. 150 gear oil should not be selected simply because the equipment uses an oil-filled design. Always check the drum motor nameplate, operating manual, and lubricant selection chart provided by the manufacturer.
What properties should drum motor oil have?
Good oxidation stability
Heat is generated by the motor and internal gear transmission during operation. When lubricant is exposed to operating temperatures over extended periods, insufficient oxidation stability can cause the oil to deteriorate. Oxidation products and deposits may form, resulting in changes in viscosity and acid number.
As the lubricant deteriorates, its ability to protect gear teeth and bearing surfaces may decrease, increasing the risk of component wear.
The selected lubricant should therefore have adequate oxidation stability and thermal stability to withstand the actual operating temperature and service conditions of the drum motor.
Appropriate kinematic viscosity
Viscosity is one of the main properties to consider when selecting oil for an oil-filled drum motor.
If the viscosity is too low, the lubricant may not form an adequate oil film between meshing gear teeth and at bearing contact surfaces. Excessively high viscosity can increase internal transmission resistance, particularly during cold starts, resulting in higher starting loads.
The appropriate ISO VG viscosity grade should be selected according to the rotational speed, gear load, ambient temperature, and internal cooling arrangement.
For products with specified lubricant requirements, follow the manufacturer's recommended viscosity grade. No. 150 gear oil should not be assumed suitable for all drum motor power ratings and sizes.
Suitable flash point and low-temperature flow properties
Flash point and pour point are two important lubricant properties, but they serve different purposes.
The flash point indicates the temperature at which an oil produces sufficient vapor to ignite under specified test conditions. It is related to the oil's volatility and handling safety. The flash point should be checked against the lubricant technical data sheet and the manufacturer's requirements. A minimum open-cup flash point of 180°C should not be treated as a universal requirement for all drum motor oils.
The pour point indicates the lowest temperature at which an oil retains a specified degree of flow under test conditions. For drum motors operating in low-temperature environments, select an oil with a pour point below the minimum operating ambient temperature to maintain suitable flow during startup and operation.
For equipment that must start at low temperatures, its low-temperature viscosity characteristics should also be checked. Pour point alone is not sufficient to determine whether a lubricant is suitable.
Good antiwear and load-carrying properties
The internal gear transmission of a drum motor is subjected to continuous torque and contact loads. Under heavy loads or demanding gear meshing conditions, the tooth surfaces may experience high contact stress.
The lubricant should therefore provide suitable antiwear and extreme-pressure properties to reduce friction and wear between metal contact surfaces.
Some industrial gear oils contain extreme-pressure and antiwear additives to improve lubrication under high-load conditions. However, oil-filled drum motors also require consideration of compatibility with motor insulation and sealing materials.
A gear oil should not be selected solely because it has strong extreme-pressure properties. Use a lubricant approved by the equipment manufacturer to avoid additives that may adversely affect motor winding insulation or sealing components.
Good rust and corrosion protection
The internal structure of a drum motor contains gears, bearings, and other metal components. If the lubricant provides insufficient rust protection, or becomes contaminated with moisture and foreign particles, corrosion may develop on internal metal surfaces.
The oil should therefore provide adequate rust and corrosion protection and maintain good cleanliness during operation.
If the lubricant shows significant discoloration, emulsification, abnormal deposits, or metal particles, inspect its condition and the internal transmission components. Change the oil and carry out maintenance when required by the manufacturer's instructions.
What lubrication precautions should be taken when using an oil-filled drum motor?
In addition to selecting the correct lubricant, the filling quantity, service interval, and oil replacement procedure also affect equipment performance.
Maintain the correct oil level:
The oil quantity inside the drum motor must follow the value specified on the product nameplate or in the manufacturer's documentation. Insufficient oil may result in poor lubrication of gears and bearings and reduce the effectiveness of motor cooling. Excessive oil can increase churning resistance and heat generation, affecting normal operation.
Always use the specified oil quantity rather than estimating the amount during filling.
Avoid mixing different lubricants without verification:
Different lubricant brands and types may use different base oils and additive systems. Mixing them without confirming compatibility can affect lubricant performance and may cause additive incompatibility.
Before changing the lubricant type or brand, confirm compatibility between the existing and replacement oils. Drain the old oil and carry out cleaning or flushing when required by the manufacturer.
Follow the specified oil change intervals:
Lubrication arrangements and maintenance intervals vary between drum motor manufacturers and models.
For example, some Rulmeca drum motors require oil changes at specified intervals, while certain sealed Interroll drum motors do not require routine oil changes under normal operating conditions. Oil replacement is only necessary in specific circumstances.
The oil change interval of one brand or model should not be applied directly to another. Follow the equipment manual and consider operating hours and lubricant condition when planning maintenance.
Custom machining of drum motor and related precision components
Drum motors contain shafts, end covers, gear-related components, bearing housings, and other transmission parts. Different models and drive configurations have specific requirements for component dimensions, machining accuracy, and assembly fits.
For non-standard equipment, we can manufacture custom shafts, gear-related components, mounting connections, and other precision structural parts according to customer drawings. Both single-piece and small-batch production are available.
Hansheng Automation also provides precision machining for components used in various industries. These include functional parts for tobacco packaging and filling machinery, as well as yacht accessories and precision structural components for RC racing cars. We support custom machining based on customer drawings and specified dimensions.
