WinGD X72DF - Page 45

Marine Installation Manual 2021-08 2-7
2 Engine Power and Speed
2.5 Power range limits
X72DF
Line 5
Engine Operation
Power Limit
Admissible power limit for engine operation. The line is separated by the break-
points listed in Figure 2-3,  2-6.
Line 6
Transient Operation
Power Limit
Maximum power limit for transient operation. The line is separated by the break-
points listed in Figure 2-3,  2-6.
Line 7
Nominal Engine
Characteristic
Nominal engine characteristic curve that passes through the CMCR point is de-
fined by the propeller law:
Formula 2-3
Line 8
Light Running
Propeller Curve
Propeller curve with a light running margin (typically between 4% and 7 %).
The curve is defined by the propeller law with a constant, governed by the se-
lected light running margin (Formula 2-4).
Formula 2-4
where:
P
LR
........... = propeller power at selected light running margin [kW]
P
CMCR
....... = CMCR engine power [kW]
n ............... = selected engine speed [rpm]
n
CMCR
....... = CMCR engine speed [rpm]
C .............. = constant
LR ............ = light running margin [%]
Line 9
CMCR Power
Maximum power for continuous operation.
Line 13
110 % CMCR Power
Constant power overload limit, available for testbed operation and emergency
operation according to SOLAS Regulation II-1/3.6.
Engine Operation
Power Range
Line 5, Line 1 and Line 9 form the curve for the engine’s operation power range
limit, as defined by Formula 2-5,  2-8. Each component is governed by different
coefficients (see Table 2-1,  2-8).
3
CMCR CMCR
Pn
Pn
æö
÷
ç
÷
ç
=
÷
ç
÷
÷
ç
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3
LR
CM CR CM CR
P
n
C
Pn
æö
÷
ç
÷
ç
=⋅
÷
ç
÷
÷
ç
èø
3
1
1
C
L
R
=
+
æö
÷
ç
÷
ç
÷
ç
÷
ç
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