Motors - Frequency of Lubrication

GA Jreaf, exactly contact the supplier on that or read the engines manual, it should be in there.

They should have some table on when the oil needs to be changed depending on the revs used

Assume you are talking grease lubrication.

Go to the bearing catalogue (on line) of any reputable bearing manufacturer and you will find calculations for regreasing interval and quantities to be applied to a specific size of bearing at the load and speed conditions that apply to your specific equipment.

As JRaef indicates, there is no simple answer for setting lubrication intervals. The motor manufacturer should be the primary source for lubrication intervals and procedures. However, if the bearings have been replaced and are no longer as specified by the motor manufacturer, the recommendations of the bearing manufacturer should take precedence.

Several factors will affect the ideal maintenance interval. The determining factors will be:

• type of bearing
• type of lubricant
• environment

Type of bearing: Sealed, permanently lubricated bearings require no additional lubricant over the life of the bearing. For an older motor, it is always advisable to check any maintenance records for the possibility that the original open-cage bearings may have been replaced with sealed bearings. Forcing grease into a sealed bearing can cause failure.

Type of lubricant: Water-soluble and high-temperature greases tend to need more frequent lubrication. Oil-lubricated bearings should never need oil to be added, but occasionally the oil should be drained and replaced (with the motor off). If you need to add oil regularly, you have a leaking oil seal.

Environment: Higher temperature applications will need more attention, particularly if the conditions are near the top of the lubricant's acceptable temperature range.

As others said, the first information will come from the motor maker. But, we should consider: Type of bearings and sealing system. Grease or oil lubrication and types Information from: -Lubricating makers- specially lub type and suitability for the aplication -bearings makers- lub quantities and expected life of lubricants and bearings (compare with motor makers) Position of the motor axis (horizontal or vertical-tipically vertical has to be relubricated double) Type of load Speed of the motor Environment, specially temperature and moisture and contaminants. Considering the above, we can stablish the base criteria and define the relubrication time and quantities per bearing I red a good paper from Exxon Mobil- Guide to electric motor lubrication, not specifically for continuous running motors, but giving good general advice.

You've got some good answers here; but the most important one is that it depends on the motor application.

If your question is coming from the industrial world it pays to seek out some professional advice; but please do show some respect to those who would help you by taking the time to do your homework and be prepared to describe in detail the type of motor in question and how it is being used; "continuously running" is a bit short on detail.

If you are dealing with an application in the consumer world this falls into the "when all else fails read the instructions" category as suggested in answers already given. Lacking any more wisdom on the subject you are best advised to follow an "if it ain't broke don't fix it" course. In otherwords, wait til the motor starts making strange noises while running, especially when starting up cold, and then follow the appropriate suggestions already given in this thread.

Note that the vast majority of consumer products, especially those that don't have internal combustion engines, are designed to never need lubrication by the user. So you are best guided by the advise that you shouldn't try to lubricate it until you are sure such action is needed. A continuous or rapidly cycling new noise from a motor is a good tip off.

There are always exceptions. I live with one in my own old (4 years) Windows 2000 pro computer. The tiny cooling fan on the video card started making noise and alternately slowing and speeding up a couple of years ago. This caused the video card to fault after an hour or so running and freeze the computer. I quickly decided that the fan with its tiny sleeve bearing brushless DC motor was the culprit and went on a fruitless search for a replacement. At that point I decided to take the lubrication route (I know a bit about such things). I removed the fan to my work bench, lifted the sticker covering the shaft and bearing and put about 0.05 ml of Mobil 1 5W-30 oil in there. Reassembled and it worked fine for about 6 months and then repeated the process when it got noisy again. I've been going like that for 2 years.

Ed Weldon