We are in the process of trying out a new electronic governor(Woodward APECS DPG-2201-00X Digital controller)for our DG set. The DA steady state speed of the DA is fluctuating continuously by about + or - 3 rpm (rated speed 1500 rpm)at all loads. The governor specs give a steady state speed band of + or - 0.25%. Is my governor performing satisfactorily? How do i interpret the specification of steady state speed? Is this fluctuation acceptable or further fining tuning of the controller is required?
0.25% of 1500 rpm = 3.75 rpm which appears to be less that the observed 3 rpm fluctuation. This appears to meet the specification, but I would be concerned if there were 3 rpm variation with generator under load. Make sure you have a second tachometer to confirm speed variation. Discuss speed variation with engine, generator, and control vendors.
Walt
Posts: 1084 | Location: Massachusetts | Registered: 27 April 2005
The fluctuations are observed at 75% load and 100% load (Rated 350 kW). We had specified a requirement of max allowable fluctuations of +/- 0.75 rpm at steady state. What is achieved is around +/-3.0 rpm. Woodward rep says that this is the best he can do. Can this be improved further?
<vimalkumar s>
Posted
Walt, the rpm during the trials was measured from the frequency output generated by the alternator, by taking a feed from the digital frequency meter. As per your advise, i will try using a different frequency meter.
A different frequency meter was used and the same fluctuations were observed. Then Woodward sent another service engineer to program the governor. finally we could achieve a better steady state speed. the fluctuations now at 100% load is around +/- 0.75 rpm.
