Asynchronous Generator with a Switchable Stator Winding for Powering the Electrical Equipment of Sprinkling Machines: Research Results

Abstract

The use of a remote transformer substation to supply center-pivot sprinkling machines is very expensive. Although the rated power of the electrical equipment used in center-pivot sprinkling machines is relatively small, the transformer substation should be designied considering a larger cross-section of the power supply line than usual. One of the reasons why a larger cross-section is necessary is the inrush currents that occur in the electric motors of the mobile trolleys (sections). The use of asynchronous generators has several known advantages, such as increased reliability, smaller weight and dimensions, high power quality. However, their use is restrained by the insufficient degree of voltage stabilization and frequency stabilization. Accordingly, it is necessary to use additional control circuits or an inverter converter in order to prevent the demagnetization of the generator. Demagnetization happens due to appearance of an inrush current, which can reach 7–10 times of the rated current, when the motor load is applied. An asynchronous generator with an autotransformer stator winding can be connected both as an autotransformer star and an autotransformer triangle, which will decrease the starting current of electrical installations. The method of switching the windings of an induction generator is well suited for supplying a motor load. It is also useful if the electrical equipment is located at a large distance from an autonomous power source. The article presents the results of applying a motor load to an asynchronous generator with autotransformer and serial stator winding. The use of autonomous asynchronous generators with autotransformer stator windings and an excitation system will expand the field of application of reliable and cheaper contactless generators.