Types of greases commonly used in motors and precautions for use!
March 18, 2022
The purpose of lubrication is to reduce friction and wear; lubricating oil can also take away the heat generated by friction, thereby reducing the temperature of the friction surface and cooling. There are many types and sizes of electric motors. Generally, the selection of grease for electric motors depends on the bearing type, number of revolutions, temperature, and load. Therefore, lubricating greases with different quality requirements must be selected according to the operating conditions of mechanical equipment.
Types and properties of greases commonly used in motors Calcium-based grease is made of calcium soap made of animal and vegetable oils and lime, thickened with medium-viscosity lubricating oil. The harder the grease, the less penetration and the higher the dropping point. It is characterized by good water resistance, it is not easy to emulsify and deteriorate in contact with water, and it can work in a humid environment or in contact with water, but it has poor heat resistance. Sodium-based grease is made of animal and vegetable oil sodium soap and thickened medium-viscosity lubricating oil. It is divided into 2, 3, and 4 grades. It is characterized by good heat resistance and poor water resistance. Calcium-sodium-based grease is made of animal and vegetable oil calcium-sodium-based mixed soap and thickened lubricating oil with medium viscosity. It is divided into 1 and 2 grades. It is characterized by good heat resistance and water resistance. The water resistance is better than that of sodium-based grease, and the heat resistance is better than that of calcium-based grease. Graphite calcium base grease is made of animal and vegetable oil calcium soap, thickened medium viscosity lubricating oil and added with 10% flake graphite. It is characterized by good wear resistance and pressure resistance, can adapt to heavy loads, and has good water resistance, suitable for lubricating equipment in contact with water or moisture, but graphite contains a lot of mechanical impurities, not suitable for rolling bearings and precision machinery. pieces. Lithium-based grease is made of 12-hydroxystearic acid or lithium stearate soap, thickened medium-viscosity lubricating oil and added with antioxidants. Divided into 1, 2, 3, 4, four grades. It is a general purpose, long-life grease that replaces calcium, sodium, and calcium-sodium greases. It is widely used in high temperature, high speed and parts in contact with water, and can be used in the environment of about 120 ℃ for a long time. It is characterized by good water resistance, good mechanical and chemical stability, good heat resistance and high dropping point. Calcium complex grease is made of calcium acetate as a compound agent to make calcium soap and thickened lubricating oil with medium viscosity. Divided into 1, 2, 3, 4, and four grades, commonly used is No. 2 or No. 3, which is characterized by good heat resistance, high dropping point, certain water resistance, and can be used in humid environments or in contact with water. It has good mechanical stability and colloidal stability, and can be used in high-speed rolling bearings. Molybdenum disulfide grease is made by adding a certain amount of molybdenum disulfide to some lubricating greases. Commonly used are molybdenum disulfide calcium base, complex calcium base, lithium base and other greases, which are suitable for bearing lubrication with particularly heavy load and high speed. Aluminum-based grease is made of aluminum stearate soap, thickened medium viscosity lubricating oil. It is characterized by good water resistance and protection, but poor heat resistance and low dropping point. Its maximum use temperature is 50 °C.
Precautions for using grease 1. In order to prevent the loss of lubricant and the intrusion of external dust and moisture into the bearing, attention must be paid to sealing. Bearing seals are divided into two categories: contact seals and non-contact seals. Motor bearing seals mostly use non-contact gap seals.
2. The grease should not be added too much or too little. Generally, it accounts for about 1/3~1/2 of the bearing chamber volume. For bearings with low speed and light load, more can be added, and bearings with high speed and heavy load can be added less.
3. Different types of grease cannot be mixed, and the old grease must be cleaned when replacing the grease.
4. Grease should be added after the bearing runs for 1000~1500 hours, and the grease should be replaced after running for 2500~3000 hours.
