DH 2 - DH 13 High Speed Balancing and Ovespeed Test Facility0 pages

DH 2 - DH 13
High Speed Balancing and Ovespeed Test Facility
For more than 40 years Schenck
RoTec has been engaged in the
development and design of special
high-speed balancing machines for
heavy turbine and generator rotors as
well as for high-speed compressors
of steam and gas turbines.
Constant exchange of experience
between Schenck RoTec and
renowned manufacturers of electrical
and turbo machinery have lead to the
development of the special DH
bearing pedestals for balancing
machines. These are equipped with
isotropically supported bearings,
providing equal stiffness in all
bearing plane radial directions, and
are suitable for use at extremely high
balancing and test speeds.
DH bearing pedestals are designed for the following
applications:
• Low speed balancing
• Checking of rotor balance at high speeds (operational
speed)
Balancing and overspeed testing under vacuum
Due to the high windage effect of bladed rotors at high
speeds and the associated power and temperature
problems, balancing and overspeed testing takes place under
vacuum conditions with a residual pressure of approx. 0.5 - 2
mbar.
Explosion proof enclosure
• Dynamic straightening of flexible rotors
• Testing of material strength by operating rotors at
overspeed
• Rotor investigation in operational bearings.
All these tasks can be performed in a single rotor set up. The
most important features of these high-speed balancing
systems are shown on the next page.
Rigid bearing supports – Additional stiffness
Rigid bearing supports provide for greater stability,
particularly at high speeds. A supplementary, remote
controlled change-over facility enables the stiffness of the
bearing pedestals to be varied, thus enabling rotor resonance
frequencies to be passed through safely, and minimizing the
risk of damaging the rotor or
the balancing facility.
To protect the surroundings from the dangers resulting from
a total or partial explosion of the rotor, a variety of different
solutions can be recommended:
Longstanding experience has shown that a walk-in tunnel
design is most suitable, especially for medium or large
facilitiesFor rotors weighing up to 8 t, with outer diameters up
to 1.7 m, an axially sliding vacuum chamber with integrated
burst protection can be used. The movable part of the
chamber is equipped with several steel liners, which act as
burst protection. If the specimen bursts, the burst energy is
absorbed by deformation elements in the foundation. A
compact design enables the facility to be installed on the
shop floor.
Drive system
For high-speed balancing, overspeed testing and dynamic
straightening of flexible rotors, either a three-phase servo
motor with frequency converter or an infinitely variable DC
motor with thyristor control can be used .
Schenck RoTec GmbH
Landwehrstrasse 55
D-64293 Darmstadt
Telefon (0 61 51) 32 23 11
Telefax (0 61 51) 32 23 15
http://www.schenck-rotec.de
E-Mail rotec@schenck.net