Water Source and Storage Calculations - Basic Mathematics for Water and Wastewater Operators - page 224

(Motor hp)

Hollow
shaft motor

Discharge head

Stung box

(Water hp)

(Total bhp)

Driving shaft

(Field bhp)

(Bowl bhp)

Bowl

Pump unit

Impeller

Suction bell

Screen

FIGURE 15.2

Vertical turbine pump, showing five horsepower types.

• Field horsepower refers to the horsepower required at the top of the pump

shaft. The following equation is used to calculate field horsepower:

Field bhp = Bowl bhp + Shaft loss (hp) (15.9)

• Bowl or laboratory horsepower refers the horsepower at the entry to the

pump bowls. The following equation is used to calculate bowl horsepower:

Bowl head (ft)Capacity × (gpm)

Bowl efficiency/100

Bowl bhp (lab bhp) = (15.10)

3960 × ( )

• Water horsepower ( whp ) refers to the horsepower at the pump discharge.

The following equation is used to calculate water horsepower:

Fieldhead (ft)Capacity (gpm) ×

3960

Water hp = (15.11)

or the equivalent equation

Fieldhead (ft)Capacity (gpm)
33,0

×
00 ft-lb/min

Water hp =