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High Speed Balancing and Overspeed Test Facilities DH 2 - DH 13 - Schenck South Africa

For more than 70 years Schenck RoTec GmbH has been the world's leading supplier of special high-speed balancing facilities. These are used for balancing of large power plant turbines and generators, high-speed compressors, industrial steam and gas turbines and complex testing of jet engine components. In a constant exchange of experience with our customers, we are developing the balancing facilities and special bearing pedestals of the DH series.

Main areas of application are:

  • High speed balancing at operational speed
  • Low speed pre-balancing
  • Dynamic straightening of flexible rotors
  • Testing of material strength by operating rotors at overspeed
  • Rotor investigation in operational bearings
  • Research & development of jet engine components
Bearing Pedestals

Our DH series bearing pedestals 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. The stiffness of the bearing supports can be changed through remote-control. This avoids passing through rotor resonances, and ensures high stability especially during over speed tests.

Measuring System

Today, the latest generation of our PC-based expert system CABflex3 is used to balance flexible rotors. The measured values are recorded and stored in raw data format in order to allow the greatest possible flexibility in the analysis of the data. A wide variety of pick-up types can be used. The number of channels is freely configurable. In addition to the calculated correction weights, using the influence coefficient method, various evaluations such as Bode and Nyquist diagrams are available. Calculation of modal residual unbalance, orbit, runout profile, FFT analysis package, bending line, correction optimization and prognosis are just a few of our software options. Network capability and remote diagnostics via modem or Internet complement the software options.

In addition to the moving coil pick-ups installed in the DH series bearing pedestals for unbalance measurement, non-contacting sensors can be used to measure shaft vibration. As a result, the behavior of the rotor in the sleeve bearings can be examined. In particular, rotor deflections at certain locations can be determined, for example on overhanging shafts or in the rotor center.

Balancing Facility

In order to protect the environment from the dangers of a completely or partially bursting rotor, the construction of a protective structure is necessary. Based on the individual customer requirements and the respective rotor spectrum, Schenck elaborates the most suitable facility concept. For rotor weights up to approx. 12.5 t and 2.0 m diameter, a moveable vacuum chamber with integrated burst protection can be used. The movable part consists of several steel layers, which serve as burst protection. In case of a rotor failure, the occurring energy is absorbed by deformation elements in the foundation. The compact design of this facility allows installation in the workshop area. For medium and large size balancing facilities the construction of an explosion-safe tunnel or bunker is the most economical solution. Thus, rotors with weights up to 400 t and 10 m diameter can be safely tested.

Schenck has the capability to supply complete facility engineering, civil construction works and the entire mechanical part of a high speed balancing and overspeed test facility. This also includes electric main drive, turbo gear, oil supply and evacuation system and much more. Our portfolio ranges from pure engineering work to the turn-key delivery of a complete DH series facility.