UNZA pump electric motor retrofit design and local manufacturing proposition

Abstract

This research work was to provide a locally produced electric motor to drive the UNZA pump.The work was carried out by using the UNZA pump parameters and electric motor material from published works on the electric motor design and manufacture and real experience from examining electric motors in service in Zambia both in the field and in the workshop. The University of Zambia pump data was used to develop a motor of 5.28 kW, 50 Hz, 380V rating.To achieve this objective complete electrical and magnetic properties of the induction motor with the above rating were calculated. From the determined magnetic and electrical values stator and rotor laminations and wiring configurations were determined.The stator and rotor diameters calculated exceeded the space provided in the UNZA pump. The pump casing and motor casing to accommodate the developed induction motor was made bigger, while the impeller and diffuser casing remained the same.The plant to manufacture the electric motor was designed using a hybrid combination of cellular and process layout to arrive at an optimal plant design. To be profitable the plant was designed to produce 3000 electric motors per year. At this level of production the ROI was 8%, IRR 37.6% PBP 2.4 years, BEP 1433 units and unit cost at K1500000.