How do you calculate bearing grease?
To calculate grease quantity, you need the bearing’s physical dimensions (primarily the outside diameter and width). Once you have these two measurements (in inches), you multiply them together and then multiply by 0.114. The resulting answer is the grease quantity in ounces.
What is the viscosity of bearing grease?
Grease is usually lithium, with a normal viscosity of 100 centistokes. This typically has a maximum operating temperature of 121 C (250 F), but it is usually limited to a service temperature of 93 C (200 F).
How much grease should be applied to a bearing?
Open angular contact thrust ball bearings for screw drives should be lubricated with a grease quantity that fills ~ 25 to 35% of the free space in the bearing. Freshly greased bearings should be operated at low speeds during the running-in period.
How do you measure viscosity of grease?
Shear viscosity – a practical test In these cases, a rheometer (rotational viscometer) is used. It measures the change in “dynamic viscosity” or shear viscosity based on 1.5 ml of grease. This allows information about the change in penetration to be obtained indirectly.
Can I grease a bearing while it’s running?
Care must be taken to follow the simple rule of 1-2 seconds between grease gun strokes and to grease while the motor is running. NEVER use an electric grease gun to grease an electric motor. A disadvantage of shielded bearings is an increase in friction and temperature of the bearing.
When should I stop greasing?
Measures to Follow You can also avoid over-lubrication by practicing the following measures: Stop greasing if you note back pressure that is not normal. Check to see that the exhaust ports on a machine are free from debris, including hard crust. Slowly pump the lubricant into a machine’s bearings for several seconds.
How do you choose motor grease?
When determining the proper grease for your application, consider: Viscosity: Oil viscosity should be appropriate for the load and speed of the application at operating temperature. The typical mineral oil viscosity in an electric motor grease is in the range of Kinematic Viscosity 90-120 cSt @40°C.
What is fluid viscosity formula?
The dimensional formula of viscosity is [ML-1T-1]. The viscosity of liquids decreases rapidly with an increase in temperature, and the viscosity of gases increases with an increase in temperature. Thus, upon heating, liquids flow more easily, whereas gases flow more slowly.
How do you calculate the amount of Grease in a bearing?
The amount of grease during each relubrication procedure can usually be calculated by simply looking at a few bearing parameters. The SKF formula method is frequently used by multiplying the bearing’s outside diameter (in inches) with the total bearing’s width (in inches) or height (for thrust bearings).
How do you calculate the viscosity of a bearing?
You can determine the rated viscosity, ν 1, from diagram 2, using the bearing mean diameter, d m = 0,5 (d + D) [mm], and the rotational speed of the bearing, n [r/min]. Alternatively, you can use SKF Bearing Select to perform this calculation.
How to determine the lubrication condition of a bearing?
When a bearing has reached its normal speed and operating temperature, the lubrication condition of the bearing is: The actual operating viscosity, ν, of the lubricant can be determined from the ISO viscosity grade of the oil, or the grease base oil, and the operating temperature of the bearing ( diagram 1 ).
How to determine the actual operating viscosity of the lubricant?
The actual operating viscosity, ν, of the lubricant can be determined from the ISO viscosity grade of the oil, or the grease base oil, and the operating temperature of the bearing ( diagram 1 ).