• Speed-dependent experiments on rotation.
  • Modes of oscillation of a rotor shaft with individual masses (Laval rotor):
    • critical speed
    • self-centering
  • Modes of oscillation of a continuous rotor shaft:
    • for varying bearing spacing
    • for varying shaft diameter


  • To be bench top, Self contained apparatus for the demonstration of the critical rotational speedson simply loaded and continuous shafts
  • Shafts to be motor driven, speed controlled through self aligning bearings
  • Digital display of speed
  • Set of different shaft sizes in length and diameter
  • Rotor steel disc made of steel
  • Micro switch power cut off

This apparatus is designed to demonstrate the concept of whirling in shafts and visualize its effects in heavy rotating machinery. When shaft rotates, transverse vibration produces in it. If the shaft is out of balance the centrifugal forces produces and vibration starts. If the rotation of the shaft is equal to the natural oscillation of the shaft, then these vibrations are multiplied. In heavy machinery this phenomena is very dangerous and it must be controlled. This apparatus consists of number of shafts of different lengths and diameters, center support for shaft and end support. Shaft is coupled with motor and speed of motor can be varied to inspect the vibrations at various speeds. The modes of oscillation and resonances of rotors with continuous mass distribution can be clearly demonstrated using this unit. Due to the use of thin, elastic rotor shafts made of high-strength steel, the oscillatory phenomena can be easily understood. A range of shaft diameters and the free choice of the bearing arrangement make it possible to perform a wide variety of experiments. Adapters in the bearings compensate for different diameters, catch bearings limit the amplitude of the oscillation. The freedom of movement of the rotor is assured by an elastic coupling. A Laval rotor with discrete mass distribution can be assembled using a mass disc. As a supplement to this unit, a set of vibration sensors. These enable the path of the rotor to be displayed on an oscilloscope.