We are a facility with a number of electric motors. 3 years ago we attempted to standardize our grease and selected a lithium based grease we thought would work in our motors. It was brought to our attention recently that electric motor bearings generally come with polyurea based grease.

We have not had a noticable amount of bearing failures due to this, as far as we can tell. Our failure rate for motor bearings has gone down since we made some improvements in our motor greasing procedures.

My question is this: Knowing that we have put the wrong grease in 100+ motor bearings, what do we do? Keep using the same wrong, lithium based grease? Start using polyurea based grease on top of the lithium based grease?

Any advice or sharing of similar experiences would be helpful.

Cheers.

It is true that most most OEM grease in motors is a polyurea based with some of the newest using a synthetic from Exxon/Mobil (SHC100) Lithium based greases are not compatible with them. The oils contained in the greases are compatible, but what may happen with this is the carriers may become stiff and not lube or they may become more fluid and release the oils. It sounds like you may not be in too much trouble, but I would not go back to a polyurea now.

We are using more of the SKF Carb bearings in our motors and they are lubed with a lithium based grease while the other bearing is a deep groove ball bearing that is lubed with a polyurea. This gets confusing so in order to keep from accidentally mixing the greases, I had the oilers use button head fittings on the polyurea side and standard zert fittings on the other. It help keep an inexperienced person from cross contaminating.

Have a good one,

Gary B

We are in the exact same situation.

Our plant was built in 1980's. In late 1990's we standardized on Mobilith SHC100 (Lithium based) for most motor lubs.

So in late 1990's when we started adding SHC100 we were already mixing greases. Often times our SHC100 was added on top of Chevron SRI2. (Those two have been evaluated for compatibility). We didn't see any problems from that.

Now most new bearings/motors come with Polyrex EM (Polyurea based). I have a letter from Mobil which stated in general terms that Mobilith SHC100 (what we have standardized on) is compatible with Polyrex EM (what a lot of new bearings/motors are supplied with). That eases my concern somewhat, although there were some vague words in the letter to indicate the compatibility was not perfect. Our plan is to continue to use SHC100. If I get a chance I will request our oil lab to do a compatibility test so we can see quantitatively the change in worked penetration of the mixture.

Our lube supplier is Chevron and I have a test report from them where they have performed compatibility tests on many of the different lubes vs Chevron products. I would think that all the major lube suppliers have done similar tests. This would help relieve some of the pain of mixing lubes.

Hope everyone has a happy holiday,

Gary B