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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)

 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
 

 

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.