Wartsila ?31DF Series Product Manual page 21

Wärtsilä 31DF Product Guide
2.2.2.2 Instant Load Application
The maximum permissible load step which may be applied at any given load can be read from
the figure below. The values are valid for engines operating in island mode (speed control).
Furthermore the stated values are limited to a running engine that has reached nominal
operating temperatures, or for an engine which has been operated at above 30% load within
the last 30 minutes.
Cyclic (wave) load-taking capability can be evaluated from the figures below:
● Max instant load step = cyclic load amplitude
○ Example: With cyclic loading at average load 57% the load variation amplitude can be
Fig 2-6
Fig 2-7
DBAE248994
14%, i.e ±7% (=50% + 14%/2)
Load Steps, CS 750 rpm
Unloading Steps, CS 750 rpm
2. Operating Ranges
2-7