These pumps are deep-well electric pumps in which the motor is closely coupled to the pump and submerged into the well. The submersible pumps are single-stage /multi-stage centrifugal pumps operating in a vertical/horizontal position. Their basic operational principle is as like centrifugal pumps. Fluid enters the pump through an intake screen and is lifted by the pump stage(s). In these pumps long intermediate shafts are undesirable.