MPP Formulas for PTOs and Hydraulics

 TO SOLVE FOR CALCULATOR ENTRY* PTO Output Speed PTO RPM = ENGINE RPM x PTO% Required Engine Speed ENGINE RPM = DESIRED PTO RPM ÷ PTO% Horsepower HP = T X RPM ÷ 5252 Torque T = HP X 5252 ÷ RPM Area of a Circle A = πr2 or A = d2 X .7854 Volume of a Cylinder V = πr2 X Li ÷ 231 or d2 X .7854 X Li ÷ 231 Force of a Cylinder F = A X PSI Cylinder Extension (inches/second) EXT. RATE = GPM X 4.9 ÷ d2 Cylinder Extension (time to extend) EXT. TIME = CYL. VOLUME X .26 ÷ GPM Volume of a Reservoir (rectangular) VOL = Li X Wi X Di ÷ 231 Volume of a Reservoir (round) VOL = πr2 X Li ÷ 231 or d2 X .7854 X Li ÷ 231 Pump Output Horsepower HP = GPM X PSI ÷ 1714 Pump Input Horsepower HP = GPM X PSI ÷ 1714 ÷ E Pump Input Torque (ft.lb.) T = CID X PSI ÷ 2π Pump Output Flow GPM = CIR X RPM ÷ 231 X E Pump Input Speed RPM = GPM X 231 ÷ CIR ÷ E Displacement of Pump CIR = GPM X 231 ÷ RPM ÷ E Flow in GPM using PTO GPM = ENGINE RPM x PTO% X CIR ÷ 231 X E Velocity of Oil V = GPM X .3208 ÷ A Heat Rise in Degrees F ΔF° = HP X 746 X Inefficiency X Minutes ÷ Gallons in system ÷ 60 The following hydraulic motor formulas are calculated in inch pounds (in.lb) rather than foot pounds. To convert to ft.lb divide by 12. Motor Output Torque Continuous Tc = GPM X PSI X 36.77 ÷ RPM or Tc = CID X PSI ÷ 2 π or Tc = HP X 63025 ÷ RPM Starting Ts = Tc X 1.3 Accelerating Ta = Tc X 1.1 Motor Working Pressure T X 2 π ÷ CIR ÷ E Motor RPM RPM = GPM X 231 ÷ CIR
* CONVERSION CHART
From English Units (US) to
Système International (metric)
 T= Torque (ft. lb.) A= Area of circle (sq.in.) F= Force d= diameter r= radius π= 3.1416 (pi) Li= Length (inches) Wi= Width (inches) Di= Depth (inches) VOL= Volume E= Efficiency CIR= Cubic Inches/Revolution V= Velocity 1 Gallon = 231 cu.in.
 From To Multiply by or Divide by Cu.in. (in3) CC (cm3) 16.39 0.06102 Cu.in. (in3) Liters 0.01639 61.02 Pounds Feet (lb.ft.) Newton Meters (Nm) 1.356 0.7376 Gallons Liters 3.785 0.2642 Horsepower BTU 2545 0.00093 Horsepower Watts 746 0.001341 Horsepower KW 0.7457 1.341 PSI Bar 0.06804 14.5 PSI KiloPascal (KPa) 6895 0.000145 Pound Kilogram 2.2 0.4545 Inch Millimeter (MM) 25.4 0.03937 Mile Kilometer (KM) 1.6093 0.6214