This section is available on request - MAN Diesel & Turbo

MAN B&W 4.01
Electricity Production
Introduction
Next to power for propulsion, electricity production
<strong>is</strong> the largest fuel consumer on board. The
electricity <strong>is</strong> produced by using one or more of the
following types of machinery, either running alone
or in parallel:
• Auxiliary diesel generating sets
• Main engine driven generators
• Steam driven turbogenerators
• Emergency diesel generating sets.
The machinery installed should be selected on the
bas<strong>is</strong> of an economic evaluation of first cost, operating
costs, and the demand for man�hours for
maintenance.
In the following, technical information <strong>is</strong> given regarding
main engine driven generators (PTO) and
the auxiliary diesel generating sets produced by
MAN Diesel.
The possibility of using a turbogenerator driven by
the steam produced by an exhaust gas boiler can
be evaluated based on the exhaust gas data.
Power Take Off
With a generator coupled to a Power Take Off
(PTO) from the main engine, electrical power
can be produced based on the main engine’s
low SFOC and the use of heavy fuel oil. Several
standard<strong>is</strong>ed PTO systems are <strong>available</strong>, see Fig.
4.0 .0 and the de�signations in Fig. 4.0 .02:
• PTO/RCF
(Power Take Off/RENK Constant Frequency):
Generator giving constant frequency, based on
mechanical�hydraulical speed control.
• PTO/CFE
(Power Take Off/Constant Frequency Electrical):
Generator giving constant frequency, based on
electrical frequency control.
MAN B&W S65ME-C/ME-GI8, S60MC-C/ME-C/ME-GI7/8, S60MC6,
L60MC-C/ME-C7/8, S50MC-C/ME-C7/8, S50MC6, S50ME-B8/9
MAN Diesel
Page of 6
• PTO/GCR
(Power Take Off/Gear Constant Ratio):
Generator coupled to a constant ratio step�up
gear, used only for engines running at constant
speed.
The DMG/CFE (Direct Mounted Generator/Constant
Frequency Electrical) and the SMG/CFE
(Shaft Mounted Generator/Constant Frequency
Electrical) are special designs within the PTO/CFE
group in which the generator <strong>is</strong> coupled directly to
the main engine crankshaft and the intermediate
shaft, respectively, without a gear. The electrical
output of the generator <strong>is</strong> controlled by electrical
frequency control.
Within each PTO system, several designs are
<strong>available</strong>, depending on the positioning of the
gear:
• BW I:
Gear with a vertical generator mounted onto the
fore end of the diesel engine, without any connections
to the ship structure.
• BW II:
A free�standing gear mounted on the tank top
and connected to the fore end of the diesel engine,
with a vertical or horizontal generator.
• BW III:
A crankshaft gear mounted onto the fore end
of the diesel engine, with a side�mounted
generator without any connections to the ship
structure.
• BW IV:
A free�standing step�up gear connected to the
intermediate shaft, with a horizontal generator.
The most popular of the gear based alternatives
are the BW III/RCF types for plants with a fixed
pitch propeller (FPP) and the BW IV/GCR for
plants with a controllable pitch propeller (CPP).
The BW III/RCF requires no separate seating in
the ship and only little attention from the shipyard
with respect to alignment.
198 57 40-2.0