Design and application of large solid-rotor asynchronous generators

Problems in connection with the design and operation of turbo-type generators in certain special cases have been such as to indicate that the characteristics of the asynchronous generator are worthy of consideration. Such generators are not new, but relatively few have been commissioned and these are of small output. They are virtually induction or asynchronous motors, driven above synchronous speed by a prime mover and drawing their magnetizing current from other synchronous machines on the system or from capacitance available therein. The first part of the paper deals with the general principles of such generators, followed by a consideration of the characteristics and problems involved in their design, including core end heating and rotor surface heating. Consideration of the operation of the asynchronous generator enables an estimate to be made of the probable limits of asynchronous heating resulting from loss of excitation on synchronous generators, of the use of asynchronous generators as shunt reactors and their use on the high-speed lines of cross-compounded units.