Submersible pumping plant

Submersible pumping units have been developed to a sufficiently high degree of reliability and efficiency to capture a large part of the field previously held by the conventional borehole pump with surface motor. The paper commences with a description of the submersible pump and the submersible motor as separate units, together with sectional drawings, constructional details and performance characteristics. An investigation is made of the efficiency, testing and behaviour of the pump and motor under abnormal and transient conditions of starting, zero-head operation and reverse rotation, details being given of the energy dissipation and the turbine phases of the pump and of the runaway speeds attained in the reverse rotation. The question of optimum diameter of the pump set and borehole for water-supply installations is examined from the economic aspect, and the implications of corrosive waters are studied. Problems arising from the linkage of the pump to the motor include the radial and axial loadings from pump to motor thrust bearings, the effect of these loadings in producing upthrust and downthrust and the motor starting-torque investigations.