Pump and Motor Purchase Costs

For other type centrifugal pumps and other materials of construction, the f.o.b. purchase cost is given by  

of Stages Shaft rpm Case-Split Orientation Flow Rate Range (gpm) Pump Head Range (ft) Maximum Motor Hp Type Factor [fj in Eq. (16.15)] 

A centrifugal pump is usually driven by an electric motor whose cost is added to the pump cost from Eq. (16.15). The size parameter for the motor is its power consumption, Pq, which is determined from the theoretical horsepower of the pump, Pj, its fractional efficiency, -qp, and the fractional efficiency of the electric motor, by the equation  

purchase cost of an electric motor depends on its power consumption, Pq, the rotation rate of its shaft, and the type of motor enclosure. Cost data are given here for two common motor speeds (3,600 rpm and 1,800 rpm) and three common types of motor enclosures  

drip-proof enclosure, which is designed to prevent the entrance of liquid and dirt particles, but not airborne moisture, dust, and corrosive fumes, into the internal working parts of the motor. 

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