I'm new to this forum and have found the information priceless. Have searched this site for information but I haven't found what I need. We have many many pieces of equipment that have lube filled gearboxes with less that 1 HP motors driving them. I know the equipment manufactures recommendations on lube changes, but would like to extend out further than the year that we currently do. Any help is appreciated.

You mean you want to change the oil based on their conditions rather than time-based? If yes, I guess you need to monitor and test the oils periodically.

To extend the oil change period, I think you need to have contamination control in place to prevent oil contaimination even the new oils delivered to your site.

Not that I want to push any particular product but you might want to consider the Mobil SHC series of lubricants. These are synthetics but are relatively "friendly" in terms of compatibility with seals, internal paints, etc.

John

Mike,
what are the issues a) cost of the work "labour and material" b) downtime c) warrantee concerns with the OEM?
extending the oil drain interval is risky unless it is done in a controlled way. Your rationalisation to proceed needs to be based on the drivers(issues). You might want to consider an oil analysis sampling/analysis regime on 10% of your gbx's. Choose the ones that you feel are the hardest used i.e. most uptime worst operating conditions (heat/dirt) Sample these 1 month after the oil is changed again at 6 months and again at 1 year. Assuming the oil passed the 6 month sampling test and still remained "in spec" at the 1 year interval, you now have a resonable rational for considering another extension to the oil change. Keep sampling perhaps at 3 month intervals. As soon as you see some "meaningfull" parameter trend change reduce the sample interval. Now you will determine a MTTF for the oil in that particular set of gbx's. Chances you will have now understood that the oil is still good or needed to be changed before the 1 year.
We have had some very good sucesses with extending the oil change interval by this exact method. Periodically you will need to re-visit the applications just to ensure the operational context hasn't changed and consequently the test results would be different (time to start over). Depending on the results of your condition monitoring program you might want to look some alternate lubricant types i.e. synthetics. However you are better off determining if the application requires these products or not, why waste the bosses money when you are obviously trying to save it by your question.
good luck.....

In order to extend the lubricant change several things need to be considered - lubricant used, gearbox lube capacity, fluids analysis, and ease of lubricant change to name a few. Changing lubricants to one with better oxidation stability may be something to consider. Performing fluids analysis will let you know when the lubricant needs changing and if any problems in the gearbox need to be addressed. Also having fluids analysis reports will back up any warranty issues you might have with the gearbox manufacturer. Working with your lubricant supplier and/or a quality fluids analysis lab will help you answer these important questions and get you headed in the right direction.

Mike,
We are also going to the shc oil in our grbxs.We also filter the grbxs on the run and sample after we have finished . The smaller grbxs we make sure the filter pump and lines are full of oil so as to maintain the correct level during filtering . We have had good success with this procedure . We use the Parker Guardian filter pump .

A couple of you indicated that you had gone to the Mobilith SHC series of sythetic lubricants. When you made this change did you increase your oil change intervals or if condition based did your oil change intervals increase, by how much?

From the motor size I expect that the gearcases in question are of small lubricant capacity. Here, as in many pump bearing housings and other equipment, the quantity of lubricant used is small and changing the lubricant type or vendor may have little value returned. The change interval is driven by particle generation which will continue at some level regardless of lubricant. Life of the lubricant or its additive package is not reached. Superior lubricants costing several time more aren't a cost issue, but whatever you spend the drain interval stays about the same in order to remove particles. Just something to consider.

I got an email from a learned colleague and friend who asked me to post this reply:


1. There is a high probability that gear speed reducers intended for general purpose applications up to and below 1 hp (~.75 kW) have a design life of only 5,000 hours. In those instances, upgrading to the next (larger) size unit will often make more economic sense than attempting to fine-tune oil replacement intervals.

2. One respondent correctly pointed out that oil contamination should be avoided. We have reason to believe that many “vented” gearboxes would do better not being vented (an estimated 2 billion automotive and residential refrigeration compressors have bearings and operate happily in non-vented systems). Also, it will often make economic sense to fully seal the oil-flooded bearings of these gearboxes by retrofitting dual-face magnetic seals.

3. After accomplishing better sealing by discontinuing breathing in and out of vents, and by using dual-face magnetic seals, it will always make economic sense to use appropriate synthetics. Some of these synthesized hydrocarbon lubricants can be obtained from the major oil companies, others are best obtained from knowledgeable---but smaller---lube providers that often use proprietary additive packages. These additives take into account the material used in, and application rigors imposed on, the gear units or gearboxes at issue.

Note from Terry O: There are only a few people who could have made the recommendations above - so you might be able to guess. Take it from me - the advice is worth serious consideration.

This particular Mr Machinery Specialist tends to recommend modifications. In other posts, some have raised concerns before considering modifications eg do the basic right first. How to address these concerns?