Six-phase turbine generators are commonly used in the modern Russian power industry when constructing power-generating units of more than 1000 MW. Issues of operation conditions of a six-phase turbine generator could be studied by analogy with three-phase machines based on equations of state for two mutually perpendicular axes of the Park-Gorev type written for an idealized machine. The investigation is simplified if the real machine whose rotor and stator windings are electromagnetically coupled is replaced by equivalent circuits with only electrical coupling between its components. Equivalent circuits could be created by representing the variables in vector form and investigating the steady-state, transient and sub-transient conditions. These circuits have a common structure and differ only by their parameters. In this case, a broad range of steady-state and transient problems could be studied, including those with different loads of three-phase systems. In addition, equivalent circuits could be used for studying the operation conditions of power-generating units, the operation problems of energy systems, and so on. The conditions of steady short circuits of a turbine generator are considered as an example. The obtained results correspond with the experimental values found from serial production tests.