Regarding grease frequency on small to meduim size motors does anyone have a generic time based frequency recommendation. Looking at the EPRI (Electric Power Research Institute) lubrication guidelines it seems they have pushed out the grease intervals considerably from what I remember seeing in the past. What are you guys in the power generation industry doing ?

We have never found a good time based frequency for greasing our motors. One of the reasons is that the motors change over time and clearances open up which changes the amount of grease that goes to the motor bearing and the amount of grease you lose to other parts of the motor. We use a sonic attachment to our grease gun to determine when a motor bearing needs to be greased and we always try to use the least amount of grease that we can.

Hi, from the wear debris lab view,
ensure you can get grease samples from in between thew loaded rolling elements, we use the vacuum gun and slip the hose right into the bearing and pull a hard vacuum until we get 75-100 mm of solid grease up the sample hose, using the cap ram the hose into the bottle and send to lab,
At the lab we cut the hose into short 1 cm section without disturbing the grease and place in shaker with solvent and liquidate the grease, filter and slide mount
Under the microscope we check for oxides and wear debris and adjust the grease flow until black oxides reduce to an acceptable level and we have not replaced any bearing we are monitoring with this system.

Motor re lubrication depends on the type of bearing, the speed, the temperature, the environment the motor is exposed to. This information combined with the actual grease service life information, SKF ROF Test, FAG FE 9 Test, ASTM 3306 provided by your lubricant manufacturer determines the re lubrication interval. This means every grease has a different re lubrication interval. As over lubrication of motors is critical you should use a lubricant with a long re lubrication interval combined with a electro mechanical single point lubricator as provided by www.lubconusa.com

I have been using the NP7502 guidelines myself.
I would love to try other methods like the sonic attachment to the gun however its hard enough getting operations out there to do the actual lube at a set frequency verses periodic checks.
OR its not ALARA effective.The SKF calcs verses NP7502 are very similar. SKF does use less amounts of grease at an increased frequency verses NP7502 more grease less frequency. We have been sucessful so far following these guidelines.

Are you willing to try an elctro mechanical lubricator as per attachment. We will talk at Noria Reliability 2005 conference about this subject. Small quantity lubrication more frequent. Has also the benefit in case of bearing current that we always replace the burnt grease with fresh one
Roland Metelmann

www.lubconusa.com