22 HANDBOOK OF ELECTRICAL ENGINEERING
Figure 2.3 Single-shaft gas turbine.Figure 2.4 Two-shaft gas turbine.In a two-shaft gas turbine the compressor is driven by a high pressure turbine called the
compressor turbine, and the generator is driven separately by a low pressure turbine called the
power turbine.
The basic arrangement is shown in Figure 2.4.
Two-shaft systems are generally those which use aero-derivative engines as ‘gas generators’,
i.e. they produce hot, high velocity, high pressure gas which is directed into the power turbine. Some
light industrial gas turbines have been designed for either type of drive. This is achieved by fitting a