PRINCIPLES OF BALANCING If the centre of gravity of a rotating machine element does not coincide with its centre of rotation, then the machine is said to be unbalanced. When the machine is stationary, the off-centre mass causes the machine element to settle in a fixed position. (Fig. 4-1)
As the machine element rotates, a centrifugal force· associated with the off-centre mass develops and imposes a fluctuating load on the shaft support bearings as shown in Fig. 4-2.