1)
PTO shaft design rating, engine output may be lower
17.6 Input data for torsional vibration calculations
A torsional vibration calculation is made for each installation. For this purpose exact data of all components
included in the shaft system are required. See list below.
Installation
•
Classification
•
Ice class
•
Operating modes
Reduction gear
A mass elastic diagram showing:
•
All clutching possibilities
•
Sense of rotation of all shafts
•
Dimensions of all shafts
•
Mass moment of inertia of all rotating parts including shafts and flanges
•
Torsional stiffness of shafts between rotating masses
•
Material of shafts including tensile strength and modulus of rigidity
•
Gear ratios
•
Drawing number of the diagram
Propeller and shafting
A mass-elastic diagram or propeller shaft drawing showing:
•
Mass moment of inertia of all rotating parts including the rotating part of the OD-box, SKF couplings
and rotating parts of the bearings
•
Mass moment of inertia of the propeller at full/zero pitch in water
•
Torsional stiffness or dimensions of the shaft
•
Material of the shaft including tensile strength and modulus of rigidity
•
Drawing number of the diagram or drawing
Main generator or shaft generator
A mass-elastic diagram or an generator shaft drawing showing:
•
Generator output, speed and sense of rotation
•
Mass moment of inertia of all rotating parts or a total inertia value of the rotor, including the shaft
•
Torsional stiffness or dimensions of the shaft
•
Material of the shaft including tensile strength and modulus of rigidity
•
Drawing number of the diagram or drawing
Flexible coupling/clutch
If a certain make of flexible coupling has to be used, the following data of it must be informed:
•
Mass moment of inertia of all parts of the coupling
•
Number of flexible elements
•
Linear, progressive or degressive torsional stiffness per element
•
Dynamic magnification or relative damping
•
Nominal torque, permissible vibratory torque and permissible power loss
•
Drawing of the coupling showing make, type and drawing number
Product Guide Wärtsilä 34DF - 3/2012
149
Product Guide
17. Power Transmission
