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Hydraulic Motor Calculations


Hydraulic Motor


GPM of Flow Needed for Fluid Motor Speed

Motor Displacement (in3 per rev)   Motor RPM        GPM Flow Required
Example: How many GPM are needed to drive a 3.75 cubic inch motor at, 1500 rpm?
Formula: Motor Displacement x Motor RPM ÷ 231 = gpm


Fluid Motor Speed from GPM Input

Gallons per Minute (GPM)        Fluid Motor Displacement (in3)      RPM
Example: How fast will a 0.75 cubic inch motor turn with 6 gpm input?
Formula: 231 x GPM ÷ Fluid Motor Displacement = RPM


Fluid Motor Torque from Pressure and Displacement

Pressure (PSI)    Motor Displacement (in3)      Torque
Example: How much torque does a 2.5 cubic inch motor develop at, 2,000 psi?
Formula: PSI x Motor Displacement ÷ (2 x π) = torque in inch pounds


Fluid Motor Torque from Horsepower and RPM

Horsepower      Motor RPM      Torque
Example: How much torque is developed by a motor at 12 horsepower and 1750 rpm?
Formula: Horsepower x 63025 ÷ RPM = torque in inch pounds


Fluid Motor Torque from GPM, PSI and RPM

Gallons per Minute (GPM)  Motor PSI     Motor RPM    Torque


Example: How much torque does a motor develop at 1,200 psi, 1500 rpm, with 10 gpm input?
Formula: GPM x PSI x 36.77 ÷ RPM = torque in inch pounds


This company assumes no liability for errors in data nor in safe and/or satisfactory operation of equipment designed from this information.