I think John and Erik´s advice are good and logical and can be used unless you can have a OEM suggestion that is possibly the best. Olov

The alarm and trip limits are about 190 micrometer and 260 micrometer Respectively for a 250 MW turbine.

regards

M.Nagar
Nubaria power station

Egypt

Nagar,
As mentioned in my previous post, I use bearing clearance to set alarms for typical sleeve bearing machines. For large machines with bearing clearances larger then 10 mils, I like to set the maximum displacement at 10 mils pk-pk. Most of the time after reviewing rotor dynamics(amplification factor) and internal clearances, 10 mils pk-pk is a reasonable value to minimize internal damage. Managers expect a machine that has tripped on high vibration to be broken and not restarted to run for 6 month's until the next opportunity.