Oil leak inside 9A5 generator

[stratford74]

We have on site a GE design 9A5 generator, brush less , with ORION journal bearings with pads. During operation it was triggered a high liquid level detection alarm. By opening the roof drain plug, we see a total drainage of 2 liters per day, with bearing lube oil flow at 18 liters per minute. We saw also oil on the air ducts of pilot exciter. Quick inspection done inside the windings from air leakage filters manhole did not reveal significant oil leaks, only oil droplets. Generator oil pressure is stable, lube oil tank level is stable, no abnormality is seen in vibrations, metal temperatures, oil drain temperatures. For sure there is no water leak from above installed coolers. Do you have any experience with oil leaks in this type of generator or similar? Thank you in advance.

 

[dougarthur42]

I am not exactly familiar with your generator but may have some useable info. We use a vapor extractor on our lube oil tank which pulls(keeps) a slight negative pressure (vacuum)on the tank. This makes it so return lube oil cannot build up enough pressure to enter the air chambers. Any loose lube oil droplets are removed back to the tank.

We also use a makeup air blower for cooling air to our generator air chambers. As long as the make up air pressure remain positive (+2 inwc) and the lube oil vacuum remains negative (-3 inwc)we have no trouble with oil buildup, but if either is not working we have trouble similar to what you talk of.
Thanks Doug