Marine Installation Manual
2022-03
2-12
2 Engine Power and Speed
2.6 Power range limits with a power take-off installation for a FPP
X62DF-S2.0
PTO incorporation of Method 2
CMCR - Method 2
With this second method, the engine’s CMCR is determined by the propeller
power only. The PTO uses the available engine power which is not absorbed by
the propeller.
As shown in
, the available power for PTO application is between Line
8 and Line 10. Therefore, the available PTO power depends on the available light
running margin at the current time.
When considering this method, a light running margin of approximately 8 % is
recommended.
Figure 2
-
6 Power range limits for PTO operation — Method 2
The PTO power must be controlled by the ship power management system,
which ensures that the engine operating point will not exceed Line 10.
Further information
The following disadvantages must be observed for Method 2:
•
With the reduction of the light running margin (as a consequence of the
ageing hull and propeller) the available PTO power will be reduced and
must be limited by the ship power management system.
•
The PTO is typically engaged in approximately 60 to 96.5% of engine
speed. The final lower limit must be defined with the supplier of the gener
-
ator. The final upper limit must be set to the project-related CSR engine
speed.
If the requested PTO power is higher than the limits defined by Method 2, an in
-
crease in CMCR power is necessary.
SM-0350
0
0
10
20
30
40
50
60
70
80
90
100
110
10
20
30
40
50
60
70
80
90
100
110
Engine speed [% Rx]
Engine power [% Rx]
PTO operation
range (Method 2)
8
7
6
5
4
2
1
9
13
3
3a
10
P12
P04
P11
P10
B
P04 (CMCR)
P10
P11
P12
100
40
60
96
100
13.2
28.8
92.2
Breakpoints
Engine
Speed [%Rx]
Engine
Power [%Rx]
