Moment Of Inertia - Man L23/30DF Project Manual

MAN Diesel & Turbo
1687148-5.2
Page 1 (1)
GenSet
Eng. type
Number of Continuous
cylinders rating
n = 720 rpm
5L27/38
6L27/38
7L27/38
8L27/38
9L27/38
n = 750 rpm
5L27/38
6L27/38
7L27/38
8L27/38
9L27/38
*) Required moment of inertia after flywheel is based on 403 Kgm
The calucation is based on 42% engine acceleration.
Larger flywheel means lower alternator inertia demand, as total GenSet inertia is the final demand.
Selection of bigger flywheel for having lower alternator inertia demand, have to be approved by a torsional
vibration calculation.
The following flywheels are available:
J =
J =
J =
**) Incl. flexible coupling for two bearing alternator.
2015.11.27

Moment of inertia

Moments of inertia
Moments
required total
J
min
kW Kgm
2
1500 691
2100 968
2450 1129
2800 1290
3150 1451
1600 679
2100 892
2450 1040
2800 1189
3150 1338
403 Kgm
2
570 Kgm
2
801 Kgm
2
Engine + Moments of
damper inertia
Kgm Kgm
2 2
207 403
264 403
291 403
353**) 403
381**) 403
207 403
264 403
291 403
353**) 403
381**) 403
flywheel, and the most common damper.
2
D 10 30 0
L27/38S, L27/38
Flywheel
Mass Required
moment of
inertia after
flywheel *)
kg Kgm
2
1451 81
1451 301
1451 435
1451 534
1451 667
1451 69
1451 225
1451 346
1451 433
1451 554