MAN B&W S65ME-C8.2-GI-TII, Project Manual

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MAN B&W 4.04
Page 2 of 3
MAN Diesel 198 43 168.8 MAN B&W 70 – 26 engines
combinator mode. This will, however, require an
additional RENK Constant Frequency gear (Fig.
4.01.01 alternative 2) or additional electrical equip-
ment for maintaining the constant frequency of
the generated electric power.
Tunnel gear with hollow flexible coupling
This PTO system is normally installed on ships
with a minor electrical power take off load com-
pared to the propulsion power, up to approxi-
mately 25% of the engine power.
The hollow flexible coupling is only to be dimensioned
for the maximum electrical load of the power take off
system and this gives an economic advantage for minor
power take off loads compared to the system with an
ordinary flexible coupling integrated in the shaft line.
The hollow flexible coupling consists of flexible
segments and connecting pieces, which allow
replacement of the coupling segments without
dismounting the shaft line, see Fig. 4.04.02.
Fig. 4.04.02: Generic outline of BW IV/GCR, tunnel gear
178 18 250.1
Generator stepup gear and flexible coupling
integrated in the shaft line
For higher power take off loads, a generator
stepup gear and flexible coupling integrated in
the shaft line may be chosen due to first costs of
gear and coupling.
The flexible coupling integrated in the shaft line
will transfer the total engine load for both propul-
sion and electrical power and must be dimen-
sioned accordingly.
The flexible coupling cannot transfer the thrust
from the propeller and it is, therefore, necessary
to make the gearbox with an integrated thrust
bearing.
This type of PTO system is typically installed on
ships with large electrical power consumption,
e.g. shuttle tankers.