Hydraulic Calculations Data

Gear Pump:

How do I size my pump?

(6 x Width of gear(2 x Diameter of gear - Length across the gear housing) x (Diameter of gear - Length across the gear housing) / 2)

Pump Output:

How do I determine how much flow my pump puts out?

(Cu/In Displacement x RPM) / 231

Pump HP Required:

How much horsepower does it take to turn my pump?

(Pressure x Flow in GPM) / 1714

Speed of a Motor:

How do I determine the speed of my hydraulic motor?

(Flow in GPM x 231) / Cu/In Displacement

Torque of a Hydraulic Motor:

How much torque does my motor develop?

(Cu/In Displacement x Pressure) / 75.36

HP of a Hydraulic Motor:

How much horsepower does my motor develop?

(Foot pounds of torque x RPM) / 5252

Area of a Cylinder Bore:

How do I determine the area of my cylinder bore?

((Bore / 2)^2) x 3.14

Area of a Cylinder Rod:

How do I determine the area of my cylinder rod?

((Rod / 2)^2) x 3.14

Volume Needed to Extend a Cylinder:

How do I determine how much oil is needed to extend my cylinder?

((3.14 x (Bore / 2)^2) x Stroke)/231

Volume Needed to Retract a Cylinder:

How do I determine how much oil is needed to retract my cylinder?

((3.14*(Bore / 2)^2 - (3.14 x (Rod / 2)^2)) x Stroke) / 231

Extend Force of a Cylinder:

How much force does my cylinder develop on extending?

(3.14 x ((Bore/2)^2) x Pressure)

Retract Force of a Cylinder:

How much force does my cylinder develop on retract?

(3.14 x ( Bore / 2)^2 - (3.14 x ( Rod / 2)^2)) x Pressure

Volume Needed to Fill a Reservoir:

How do I determine how much oil is in my reservoir?

(Length x Width x Height) / 231

As a general rule of thumb, for every:

1 HP of the drive, the equivalent of 1 GPM @ 1500 PSI can be produced.

You can use the equations above as your handy references for calculating pump outputs, motor speeds, cylinder areas, and other important data.



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