*Article* **Feasibility Study of Direct-on-Line Energy-Efficient Motors in a Pumping Unit, Considering Reactive Power Compensation**

**Vadim Kazakbaev, Safarbek Oshurbekov, Vladimir Prakht and Vladimir Dmitrievskii \***

> Department of Electrical Engineering, Ural Federal University, Yekaterinburg 620002, Russia; vadim.kazakbaev@urfu.ru (V.K.); safarbek.oshurbekov@urfu.ru (S.O.); va.prakht@urfu.ru (V.P.) **\*** Correspondence: vladimir.dmitrievsky@urfu.ru; Tel.: +7-343-375-45-07

**Abstract:** The paper compares the economic effect of using capacitors in fixed speed drives of a pumping station when using energy-efficient motors of various types. Induction motors of IE2 and IE3 energy efficiency classes, a direct-on-line synchronous motor with a permanent magne<sup>t</sup> in the rotor, and a direct-on-line synchronous reluctance motor are considered. The comparison takes into account not only the efficiency of the motors, but also their power factor, on which the losses in the cable and transformer depend. The possibility of using static capacitors to compensate for the reactive power of motors and reduce the losses is also considered. The feasibility analysis takes into account that the motors have different initial costs. The cost of capacitors is also taken into consideration. The analysis shows that the use of static capacitors can have a significant impact on the comparison between different motors in this application. Without considering capacitors, the permanent magne<sup>t</sup> motor has the shortest payback period, otherwise the synchronous reluctance motor has the shortest payback period.

**Keywords:** centrifugal pump; direct-on-line permanent magne<sup>t</sup> synchronous motor; direct-on-line synchronous reluctance motor; energy efficiency; induction motor; permanent magne<sup>t</sup> motor; reactive power compensation
