We have had a longstanding issue with foaming in large vertical motors. This would be a 6000 HP motor w/splash lube. Any similar instances and what was done to correct the issue.

I have seen a couple of similar cases but not in motors of that capacity. The first was tracked down to air leaks but the second turned out to be moisture. Levels were reading about 100ppm kf and it wasn't until we ran offline filtration with a vacuum dehydrator that the levels dropped to >50 ppm kf (can't remember exact figures possibly 15 - 20). The foaming problem dissapeared in the hour or so it took to do the filtration. I know there are other causes but I hope this might be of some help.
MC