Basic Fluid Power Formulas

[Geo.]

Basic Fluid Power Formulas
   Fluid Pressure – (P) (PSI – pounds per sq. in.)
•   PSI = force / area (P= F / A)
   Fluid flow rate – (Q) (GPM – gallons per min.)
•   GPM = Flow / Time (Q = V / T)
   Fluid power in Horsepower – (HP)
•   Horsepower = PSIG * Flow / 1714 (P * Q / 1714)




 Actuator formulas
   Cylinder area – (A) (sq. in.)
•   A = Pi (3.14) * R2 (Radius squared)
•   Alterative - A = Pi (3.14) * D2 (Diameter squared) / 4

   Cylinder Force – (F) (pounds)
•   Force = PSI * Area (F = P * A)

   Cylinder Speed = (v) (feet per sec.)
•   Feet /sec. = (231 * Flow rate) / (12 * 60 * Area)             (v = (0.3208 * GPM) / A)

   Cylinder Volume Capacity – V
•   Volume = Pi (3.14) * R2 (Radius squared) * Stroke / 231         (V = Pi * R2 * L /231)  (L = Length of stroke)

   Cylinder Flow Rate – (Q)
•   Volume = 12 * 60 * v * Net Area 2 (squared) / 231            (Q = 3.11688 * v * A)

   Fluid Motor horsepower – (HP)
•   HP = Torque * RPM / 63025  (HP = T * n / 63025)

   Fluid motor speed – (n)
•   Speed (RPM) = (231 * GPM) * Displacement (in)3         (n = (231 * GPM) / d)

   Fluid Motor Torque – (T)
•   Torque (in. lb.) = Pressure * Displacement (1n.3 / rev) / 6.2822      (T = P * d / 6.2822)
•   Torque = HP * 63025 / RPM (T = HP * 63025 / n)
•   Torque = Flow rate (GPM) * Pressure * 36.77 / RPM         (T = 36.77 * Q * P / n)