Analytical mathematical model of the pumping unit of machine water lifting systemsK. G. Abidov, Sh.O. Zaripova, N.B. Khamudkhanova, S.A. Dusmukhamedova, M.O. Gafurova and H. BaratovE3S Web Conf., 289 (2021) 07004DOI: https://doi.org/10.1051/e3sconf/202128907004