Elastically Isolated
Generator

Example of elastic bearing of turbine foundation

YZXYX

ZZYY

Front view

Mass inertia moment
Direction
Ixx
IyyIzzInertia of massSide view

1639716 kgm2

Inertia of mass, of all optional
forces and masses, referringto the origin.

Isometric view

Isolation values

Natural frequencies
Direction

Naturalfrequencies

Frequency

Insulation inz-direction

fz:
fuz:
fxu:
fxo:
fyu:
fyo:

17,8 Hz
16,5 Hz
12,8 Hz
20,6 Hz
15,5 Hz
23,4 Hz

20 Hz
25 Hz
31,5 Hz
40 Hz
50 Hz
63 Hz

10,2 dB (-222%)
0,2 dB (-2%)-6,4 dB (52%)-11,8 dB (74%)-16,3 dB (85%)-20,5 dB (91%)

4349478 kgm2
4970879 kgm2

Ground view

Given natural frequencies occure when using above mentioned bearing materials. fz
describes the natural frequency
in vertical direction,fuz therotary natural frequency aroundthe vertical axis and fxu, fyu,fxo, fyo the sweep frequencies

around an upper (fxo, fyo) andlower (fyo, fxo) centre of rotation. In this calculation theinluence of the subgrade was
not taken into consideration.

Given insulation values are only
valid for a one-mass-springsystem. This means that themachine and fundament are
assumed as stiff masses.

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Solution

Generator borne vibrations that aretransmitted to the surrounding areas caninfluence the functionality of near-by
equipment, impact product quality, andmachinery life cycle costs.These vibrations
can affect the overall work environment of
the adjacent areas and should they become
structure borne cause damage to thebuilding or structure in which they arelocated.

Highly engineered cellular urethanematerials manufactured by Getzner
Werkstoffe called Sylomer® and Sylodyn®
are specially designed to reduce vibrationand structure borne noise for machinery
applications. The wide static load capacity
range (1.60 psi – 435.11 psi), thicknesses, anddimensions allow for Sylomer® andSylodyn® solutions to be easily customized
to the needs of your specific generator for
optimal isolation. Sylomer®, Sylomer® HD,and Sylodyn® materials have properties thatare very similar to that of a mechanicalspring. Sylodyn® is the material most like amechanical spring as it has very littledamping and can achieve natural frequencies as low as 4 – 5 Hz. Sylomer® HD is apure damper with little to no spring andAUSTRIA — Bürs GERMANY — Berlin — Munich FRANCE — Lyon
INDIA — Pune CHINA — Beijing USA — Charlotte

JORDAN — Ammana mechanical loss factor of 0.55 – 0.60.
Standard Sylomer® is a combination of bothspring and damping. Since Generators
require some internal damping during thestartup and shutdown phases standardSylomer® is the right material for generator
applications.
With special footing designs Getznerengineers are able to eliminate the loss ofperformance that is typical for prestressedsolutions. The footing design would bebased on the fact that prestress forces do
not have any inertia and therefore in turn
do not contribute to vibration insulation. By
optimizing the build up it is possible toreach frequencies below 7 Hz with abearing thickness of around 3”. This resultsin highly efficient solutions that show a– 91.6 % or 21.5 dB reduction value at therotation frequency of the motor as shownfor the 2100 kVA Sterling Wilson diesel
generator

JAPAN — Tokyo
www.getzner.com

TB EIG US en © Copyright by Getzner Werkstoffe GmbH | 06-2013

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