WinGD X62DF-S2.0 User Manual

Marine Installation Manual 2022-03 6-5
6 Engine Dynamics
6.1 External mass forces and moments
X62DF-S2.0
Power related unbalance
The power related unbalance (PRU) values can be used to estimate the risk of un-
acceptable levels of hull vibrations caused by external mass moments of first and
second order. The PRU is calculated with the following formula:
Formula 6-1 Power related unbalance calculation
where:
PRU .......... = power related unbalance
M
x
............. = M
2V
(typically), M
1H
& M
1V
(considered as well)
The M
x
and the resulting PRU values of an engine are dependent on the number
of cylinders.
The resulting PRU values are graphically displayed in the link below, along with
the likelihood of needing a compensator.
External forces and moments
The link provides dynamic characteristics data for engines tuned at R1 rating.
For other engine speeds, the corresponding external mass moments are calcu-
lated with the following formula:
Formula 6-2 External mass moments calculation for R
x
rating
where:
M
x(CMCR)
... = resulting moments for a specific engine’s CMCR
M
x(R1)
........ = moments for engine at R1 rating
n
CMCR
....... = speed of engine for a specific engine’s CMCR
n
R1
............ = speed of engine at R1 rating
(
)
()
=
x
MNm
PRU
E
ngine Power kW
()
()
2
1
1
CMCR
CM CR
R
R
x
x
n
MM
n
æö
÷
ç
÷
=⋅
ç
÷
ç
÷
ç
èø

WinGD X62DF-S2.0 Specifications

General

Brand	WinGD
Model	X62DF-S2.0
Category	Marine Equipment
Language	English