Selection of the proper components for a hydraulic system is quite simple when you use the accompanying table and chart. Here is an example to illustrate their use. Assume your requirements are: 20,000 lbs. of force, 28” stroke, and 7.5 seconds for full cylinder extension.

Step One:
The table below shows a 3” diameter cylinder will develop 21,204 lbs. of force with 3000 psi pressure.

Step Two:
A line has been drawn on the chart from 3” diameter through 28” stroke.

Step Three:
By continuing this line, it intersects 200 cubic inch displacement.

Step Four:
Another line drawn from 200 cubic inches through 7.5 seconds intersects 7 GPM.

Your Answer:
Using this example, the chart and table show that your components should be a 3” diameter 3000 psi cylinder and a hydraulic power unit with approximately 7 GPM and 3000 psi rating.

Theoretical horsepower for these values would be 12.25 hp. However, since most applications usually require maximum GPM and pressure for only a very short portion of each cycle, the electric motor of the hydraulic power unit will usually be considerably smaller (one half or less.)