## 1 Introduction
It is  
Figure 1: Schematic representation of motor geometry: (**a**) induction motors, (IM); (**b**) direct-on-line synchronous motor with permanent magnet in the rotor, (DOL-PMSM); (**c**) direct-on-line synchronous reluctance motor without permanent magnet (DOL-SynRM). known that the extraction of one ton of rare-earth metal concentrate produces 1-1.4 tons of radioactive waste that pollutes the environment [22]. A direct mains powered synchronous reluctance motor (DOL SynRM) does not have the above-mentioned disadvantages of IE4 IM and DOL PMSM. In a number of applications, synchronous reluctance motors (SynRM) which do not have starting squirrel-cage winding and magnets in the rotor are already being used when powered by a frequency converter as a more energy-efficient replacement for IM [23; 24; 25; 26; 27]. Several manufacturers offer these motors in conjunction with frequency converters [28; 29; 30]. Such SynRMs can correspond to the class IE4 [28; 31] or even IE5 [11; 25; 32], according to [33]. In recent years the scientific literature describes the latest synchronous reluctance motors with energy efficiency class IE4 and above with direct mains supply (DOL SynRM, Figure 1c). Due to the absence of electrical losses in the rotor, DOL SynRM provides higher efficiency in comparison with IM IE3, at a similar production cost [34]. As in the case of DOL PMSM, DOL SynRM is started in asynchronous mode using a squirrel-cage asynchronous winding on the rotor [35; 36; 37; 38]. Pumping systems that consume about 22% of all electricity worldwide [39] are one of the applications in which the use of energy-efficient motors is the most promising. Due to the significant cost of the frequency converter, most pumping systems use direct-powered motors [40; 41]. Although the topic of comparing the energy efficiency of different types of motors (induction, synchronous reluctance, synchronous motors with magnets) in a pumping application has been covered in a large number of studies, the comparison is usually made for motors powered by a frequency converter [23; 27; 42; 43; 44]. A comparison of the energy consumption of different types of motors in pumps with direct mains supply is considered much less often. For example, Reference [41] compares the energy-efficiency indicators of DOL PMSM and IM of different IE classes in a pump without speed control. In [41], it is also shown that when considering a typical pump cycle, energy consumption is influenced not only by the energy efficiency class of the motor but also by of its efficiency in the modes with a reduced load. In the article [45], an analysis was performed for a pumping unit with direct power supply from the mains, with a power of 11 kW and two IMs of energy efficiency classes IE1 and IE2. The payback periods (see Section 5) of replacing an electric motor of class IE1 with an electric motor of IE2 class were calculated. However, it should be noted that replacing the IE1 electric motors with IE2 electric motors is obligatory only in some countries. For example, in the countries of the Eurasian Economic Union (Russia, Kazakhstan, Belarus, Kyrgyzstan, Armenia) legislation in the field of energy efficiency until 1 September 2021 does not prohibit the use of IE1 class motors [46]. Another important factor that is not considered in [23; 41] when analyzing the energy efficiency of pumping systems is that there are power losses in the power line. Typical elements of a power transmission line are cables and transformers, the losses of which depend on the power factor of the motor. When the power factor decreases, the reactive component of the current as well as the total current increases. A number of works [47; 48; 49] report that DOL SynRM has a lower power factor compared to IM and DOL PMSM, which can lead to increased cable and transformer losses. Therefore, the study of the quantitative influence of the efficiency and power factor of the motor on the indicators of energy consumption is one of the goals of this work.