Electricity Production; Power Take Off - Man B&W L35MC6-TII Project Manual

MAN B&W

Electricity Production

Introduction
Next to power for propulsion, electricity produc-
tion is the largest fuel consumer on board. The
electricity is 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
basis of an economic evaluation of first cost, op-
erating costs, and the demand for manhours for
maintenance.
In the following, technical information is given re-
garding main engine driven generators (PTO) and
the auxiliary diesel generating sets produced by
MAN Diesel.

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
standardised PTO systems are available, see Fig.
4.01.01 and the designations in Fig. 4.01.02:
• 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 S46MC-C7/8, S46ME-B8, S42MC7,
S40MC-C9, S40ME-B9, S35MC-C9, S35MC7,
S35ME-B9, L35MC6, S26MC6
• 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.
Within each PTO system, several designs are
available, depending on the positioning of the
gear:
• BW II:
A freestanding gear mounted on the tank top
and connected to the fore end of the diesel en-
gine, with a vertical or horizontal generator.
• BW IV:
A freestanding stepup gear connected to the
intermediate shaft, with a horizontal generator.
MAN Diesel
4.01
Page 1 of 5
198 57 39-2.1