Full-scale testing of the pump unit with a frequency converter

Abstract

It is generally agreed that when using the frequency converter at pumping stations, the economic effect of its use far exceeds the losses in efficiency, and naturally, no comparison between the alternative methods of regulation is given. But, as a practice has shown at the application of the given control method, losses in efficiency can be essential. Quantitatively these losses depend on many factors (degree of regulation, type of the applied frequency converter, pumps and the driving electric motor, operating modes etc.). Therefore, for an accurate assessment of the efficiency of the control method, field tests of the unit with a frequency converter are necessary. Full-scale tests were carried out at the Teshik-Tash-1 pumping station located in the Andijan region of the Republic of Uzbekistan. The field tests consisted of determining the efficiency of the pump unit when the drive shaft speed changes. Graphical dependencies of changes in the energy parameters of the pump unit when changing the rotation frequency of the impeller shaft using a frequency converter are obtained. Tests have shown that loss values can reach significant values when using a frequency converter. If you reduce the speed of the pump impeller by 10 %, the efficiency of the electric drive (motor and converter) will also decrease by 10 %, and if you change it by 25 %, the efficiency of the electric drive may decrease by up to 40 %. The test results can be applied in the selection and feasibility study of the regulation method at irrigation pumping stations equipped with pumps of type D.