Generator Vibration

I used to use Foucault triangles. A sticky paper triangle with amplitude calibration lines on it. I don't know how to draw it in this editor and it wont let me past an image.

If you wish to insert an image in your post click the image button (little green thing that looks like a camera an shown in the image to the left) on the editor toolbar and follow the instructions. Once the image is inserted you can then move and resize it to suit your purpose

Machine builder (GE?) should have the answer for their equipment. There are numerous vibration measuring instruments on the market.

Bearings, build up of dirt, shorted windings etc, can all cause vibration. A good technichian can sort that out for you.

check the Temperature gauge located on the bearing housing lube oil discharge line. It's a clear indication of mentioned machine problem. But possible cause can only be assumed by experience/ in location.

There are numerous possible causes for vibration in rotating systems. Since you have asked about it, I assume it is vibration that is noticable to you and is presumably low frequency i.e. occurring at shaft frequency or low multiples thereof. The most common causes are rotational imbalance and/or drive shaft misalignment. If the system has fluid film bearings it could be excessive clearances or shaft orbiting.
If it is at shaft frequency it is probably imbalance. One quick thing you can do is check your foundation to make sure that your system is solidly tied down to your inertial base. (No loose or uneven footings) That is relatively easy to verify (If you can safely get at it?) with a simple vibration meter by measuring the vibration level on the concrete support foundation vs the housing footings. or the housing. If the level on the housing/footing is higher, check for loosenes and tighten things down. (Sometimes you can feel the differance by hand if it is really loose.)

For information on standards, check the web site of the Vibration Institute. They are a great source of standards information and expertise. There are many experts and sources of expertise that can help you. Check with the generator manufacturer or with a company like Bently-Nevada in Linden, Nevada, USA. Sorry I don't have the web addrsses but I'm sure you can check it out.

If you can say which brand of generator is in question, and in which turbine I may be able to help you get the information you are looking for. Also in what context are you looking for this information, (i.e. maintenance, troubleshooting, etc.)

Turn the stator slowly and determine if there is a mechanical problem on the shaft and or bearing assesbmbly like bent shaft of bearing play. If you can feel play or see eccentric movement then that is outside spec.

There may also be a magnetic imbalance between the 3-phase windings. This causes a unbalanced rotating force. First test; do a resistance test per phase and they should be about the same. The resistance is low and therefore you need large currents and a stable voltage source.