Marine Installation Manual 2022-03 2-14
2 Engine Power and Speed
2.7 Prohibited operation area
X62DF-S2.0
As seen in Figure 2-7,  2-13, the prohibited operation area of an engine is de-
fined by an engine tuned to an R1 —R2 speed. At this speed rating the restriction
exists between 70 % and 100 % speed, with a required minimum engine power at
these points of 5.8 % and 17 %, respectively. These values are governed by the
Formula 2-6 for Line 11.
If the CMCR speed rating of the engine is less than the R1 —R2 speed, the re-
quired minimum power at this point is also calculated by the Line 11 equation.
Line 11
The lowest operational power limit, between 70 % of R1—R2 speed and 100 %
CMCR speed, is defined by the following equation:
Formula 2-6
As calculated by this equation and shown in Figure 2-7,  2-13, at 70% of
R1 —R2 speed the minimum engine power equals approximately 5.8% of the
CMCR power (point E). The minimum power requirement at 100 % CMCR
speed (point F) must be calculated depending on the engine rating. Examples of
this calculation are shown further on.
Line 12
While operating at 100 % CMCR speed, the allowed engine power can range be-
tween the minimum required power (point F) and 100% CMCR power.
Field A
The available design range of the engine is defined by Line 7, Line 11 and Line
12.
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NOTE
For test purposes, the engine may run within the prohibited operation
area for a maximum of 30 minutes during testing and sea trials. This
operation is only permissible at low load and in the presence of author-
ised representatives of the engine builder. Further requests must be
agreed upon by WinGD.
NOTE
The operational design range must respect the Barred Speed Range
(BSR) limits from torsional vibration.
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