Over-greasing, getting Grease into Windings and other Poor Lubrication Practices

From Imrtwiki

Richard from Rio Tinto suggested that from hard experience they have learned that opening and cleaning out of grease relief ports on motor bearing ensure that grease is not injected into windings. They grease their motors on-line and it was pointed out that in some situations grease ports would have to be cleaned out off-line as safe access is not available on-line.

On motors that allow lubrication by grease nipples but do not have relief ports, greater care has to be taken that too much grease is not injected into the bearings. One suggestion was to use a stethoscope (or ultrasonic vibration instrument) to be able hear when grease enters the bearing and to stop adding grease. Peter from OneSteel indicated that as well as getting grease into the windings, over greasing causes increased bearing temperature, which shortens grease life. Mick from ANSTO indicated that over greasing of motors has been a problem at their site.

Another issues Peter from OneSteel highlighted was use of the wrong grease, which can have serious effect if the new grease is incompatible with the standard grease. A solution implemented at Rio Tinto in one situation was to change the type of grease nipples used so that the standard grease guns at the site did not fit the nipples on the electric motors. Another way undesirable grease mixing can occur is due to your motor repair shop using different grease to your site standard. A suggestion was to provide your site motor standard grease to the motor repair shop to make the use of incompatible grease less likely.

Contamination of grease was also discussed. This can occur directly from the environment as indicated by Blue Circle below. Other causes mentioned were not cleaning grease nipples before greasing and use of contaminated grease suppliers. Grease supply contamination is less likely when grease cartridges are used.