I am looking for documentation for generator performance standards. I am the Plant Operations Manager for a small 25 bed hospital. We had an old 75kw generator that pumped fuel out of 55 gal drums inside a bldg. OSHPD made us upgrade to an exterior unit with a skid mounted 24 hour tank. We put in a 125KW Olympian. When the generator company came out to load test the unit the load bank shut down from low power output from the generator. When 100% block load was applied the frequency dropped to about 38 Hz. The generator company came back and tweeked the governor and the load was applied without tripping the load bank. The problem I have is that at time of transfer it takes much longer than the old generator and that the frequency does not stay at 60 Hz. We transfer at less than 25% of the generators capacity and the frequency goes from 63-57 Hz. Is there any published standard of what an acceptable transient frequency is? Thanks for your input.