Measurement of eddy-current damping of small synchronous generator with two types of cylindrical solid rotor

An experimental model is used to represent a generator, the solid rotor of which is hunting about synchronous speed. The eddy-current damping factor, and hence the losses in the rotor, are measured at different stages in the construction of two different forms of rotor to assess the effect of the various components such as wedges, end rings and copper damper cage. It is found that a well-connected damper cage is particularly important in improving the damping