HORSE POWERÂ H022

A common method of measuring work. We calculate the horsepower coming out of the pump and compare it to the brake horse-power going into the pump to determine the pump’s efficiency. The horsepower coming out of the pump is called the water horsepower. The formula looks like this:

**In USCS units**

- Q = gpm.
- H = feet
- sg.= specific gravity

**In SI units**

P = 9797 x Q x H (sg.)

- P = power in watts
- Q = cubic meters per second
- H = meters

The brake-horsepower is given to you by the pump manufacturer. He records this number somewhere on the pump curve.

The following table will allow you to convert to and from horsepower units to common metric and inch units

1 watt = 1 joule per sec = 1 newton meter per second