Influence of frequency on the synchronous electrical machine parameters
The current and moment of resistance to rotation of the inductive synchronous electric machine under inductive load have been considered. For a synchronous machine with an inductive load, Theorem 1 is valid: the current amplitude in the inductive load of an inductive synchronous electric machine is independent of the rotational speed. The theorem has been proved by equating the second Kirchhoff law and the law of electromagnetic induction with reference to a rotating machine. Theorem 2 is also valid: the moment of resistance to rotation for an inductive synchronous electric machine with an inductive load is independent of the rotational speed. The theorem has been proved by analyzing the Ampere law with respect to a rotating machine. It has been established, with active load, the current amplitude and the moment of resistance to rotation depend linearly on the rotational speed. However, with capacitive load, these parameters are quadratically dependent on the rotational speed. The connection of power with frequency under various types of machine load has been proven: for inductive load, the reactive electric power is linearly dependent on frequency; for resistive load, the dependence is quadratic; at the same time, for capacitive load, the power is cubic dependent on frequency. For a synchronous capacitive machine with capacitive load, Theorem 3 and 4 are considered to be valid. Theorem 3: the voltage amplitude on capacitive load of a capacitive synchronous electric machine does not depend on the rotational speed. Theorem 4: the amplitude of the resistance to rotation moment for a capacitive synchronous electric machine with capacitive load does not depend on the rotational speed. The results are recommended to use when designing electrical systems.