Fluid Power Formulas
|
Basic Fluid Power Formulas / Hydraulics / Pneumatics
|
||
|
Variable
|
Word Formula w/ Units
|
Simplified Formula
|
| Fluid Pressure - P | (PSI) = Force (Pounds) / Area ( Sq. In.) | P = F / A |
| Fluid Flow Rate - Q | GPM= Flow (Gallons) / Unit Time (Minutes) | Q = V / T |
| Fluid Power in Horsepower - HP | Horsepower = Pressure (PSIG) × Flow (GPM)/ 1714 | HP = PQ / 1714 |
|
Actuator Formulas
|
||
|
Variable
|
Word Formula w/ Units
|
Simplified Formula
|
| Cylinder Area - A | ( Sq. In.) = ? × Radius (inch)2 | A = ? × R2 |
| (Sq. In.) = ? × Diameter (inch)2 / 4 | A = ? × D2 / 4 | |
| Cylinder Force - F | (Pounds) = Pressure (psi) × Area (sq. in.) | F = P × A |
| Cylinder Speed - v | (Feet / sec.) = (231 × Flow Rate (gpm))/ (12 × 60 × Area) | v = (0.3208 × gpm) / A |
| Cylinder Volume Capacity - V | Volume = ? × Radius2 × Stroke (In.) / 231 | V = ? × R2 × L / 231 (L = length of stroke) |
| Cylinder Flow Rate - Q | Volume = 12 × 60 × Velocity (Ft./Sec.) × Net Area(In.)2 / 231 | Q = 3.11688 × v × A |
| Fluid Motor Torque - T | Torque (in. lbs.) = Pressure (psi) × disp. (in.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 | |
| Fluid Motor Speed - n | Speed (RPM) = (231 × GPM) / Disp. (in.)3 | n = (231 × GPM) / d |
| Fluid Motor Horsepower - HP | HP = Torque (in. lbs.) × rpm / 63025 | HP = T × n / 63025 |
|
Pump Formulas
|
||
|
Variable
|
Word Formula w/ Units
|
Simplified Formula
|
| Pump Output Flow - GPM | GPM = (Speed (rpm) × disp. (cu. in.)) / 231 | GPM = (n ×d) / 231 |
| Pump Input Horsepower - HP | HP = GPM × Pressure (psi) / 1714 × Efficiency | HP = (Q ×P) / 1714 × E |
| Pump Efficiency - E | Overall Efficiency = Output HP / Input HP | EOverall = HPOut / HPIn X 100 |
| Overall Efficiency = Volumetric Eff. × Mechanical Eff. | EOverall = EffVol. × EffMech. | |
| Pump Volumetric Efficiency - E | Volumetric Efficiency = Actual Flow Rate Output (GPM) / Theoretical Flow Rate Output (GPM) × 100 | EffVol. = QAct. / QTheo. X 100 |
| Pump Mechanical Efficiency - E | Mechanical Efficiency = Theoretical Torque to Drive / Actual Torque to Drive × 100 | EffMech = TTheo. / TAct. × 100 |
| Pump Displacement - CIPR | Displacement (In.3 / rev.) = Flow Rate (GPM) × 231 / Pump RPM | CIPR = GPM × 231 / RPM |
| Pump Torque - T | Torque = Horsepower × 63025 / RPM | T = 63025 × HP / RPM |
| Torque = Pressure (PSIG) × Pump Displacement (CIPR) / 2? | T = P × CIPR / 6.28 | |