Foaming in Lub Oil

Obviously you can't if oil is found where there should be none or if there's water in the oil.

How did you notice that? Leaking ol from the journals? Is there a pressure lubrication or are oil pumps only for circulation (cooling in heat exchangers)? Hydro turbine (vertical or horizontal shaft? How many poles?) driven or fast steam/gas turbine?

Foam could typically indicate water in oil, e.g. from heat exchanger leakage.

Is oil automatically monitored for water content? Are there traces of oil in the (primary where applicable) cooling water?

Are stator and rotor ground monitored? For those sizes it's usually the case.

IMO you'd rather stop the group immediately and check what happened, if not the problems will likely increase, typically ending in an way more expensive repair and longer down time than if a thourough diagnosis is performed without delay.

What does the alternator manufacturer's Operating Manual say? How did the phone call with the manufacturer's technical helpline go? When does the Service Technician arrive to assess and service the equipment?

When running a >40 MVA generator you're supposed to have some in-house knowledge, no?

Unless it's are relatively new unit, chance are that it has been partially disassembled during preventive maintenance so you should have own in-house documents about those overhauls.

Also there are many cases where older generators are still in use but whose manufacturer no longer exist. Of course there should be a detailed documentation available, usually it's mentioned in the contracts.

Nothing to stop you running it to destruction. That way you'll know for certain what happens. Someone looking for a new job is one likely outcome.

I can't understand why you even ask the question.

Taking a 35MW generator off line is going to have financial repercussions but no where as bad as having it repaired after its failed.

What type of generator is it? In most probability it should be air cooled generator. What type of cooling does the rotor have? Is it direct cooed or indirect cooled? You have not stated how you have come to know that there is oil in the generator? Visual or alarm of liquid in the generator? How old is the generator? What type of insulation does the stator and rotor winding have? Is it class F?

Why utilities have hesitation in contacting the manufacture of the generator?