Quick link to : Table of Contents 55 Toll-Free: 1-888-WAINBEE (924-6233) www.wainbee.com55 Toll-Free: 1-888-WAINBEE (924-6233) www.wainbee.com

Fluid Power Formulas

Mechanical Horsepower

HP = d x F550 t

HP = mechanical horsepowerd = distance (ft.)F = force (lb.)t = time (seconds)

Mechanical Horsepower

HP = F x v396,000

HP = mechanical horsepowerF = force (lb)

v = velocity (in/min)

Hydraulic Horsepower

HP = P x Q x 0.000583 HP = hydraulic horsepowerQ = flow (gpm)P = pressure (psi)

Motor Horsepower

HP = s x T63,025

HP = motor horsepowers = speed (rpm)T = torque (lb.-in.)

Heat

H = HP x 2,547 H = heat (btu/hour)HP = hydraulic horsepower

Flow

Q = V x CR28.8 t

Q = flow (ft3/min.)V = cylinder volume(in3)CR = compression ratiot = stroke time (seconds)

Compresssion Ratio

CR = Pg + Pa

Pa

CR = compression ratioPg = gauge pressure (PSIG)Pa = atmospheric pressure (PSIA)

Air Motor Speed

RPM = 1728 Q Disp

RPM = air motor speedQ = flow (cfm)Disp = motor displacement (in3/rev)

Flow Coefficient (Cv)

Cv = flow coefficientQ = SCFMG = specific gravity of flowing medium (G = 1

for air)Tabs = absolute temperature (460+ °F)ΔP = pressure drop (PSI) static to static pressurePo = outlet pressure = (inlet press - ΔP)Pa = atmospheric pressure

Pneumatic Cylinder Rod Speed

V = S x 60 t

V = cylinder rod speed (in./min.)S = stroke (in.)t = stroke time (seconds)

Hydraulic Tank Cooling

Hp = 0.001 x Aw x ΔT Hp = cooling power (HP)Aw = wetted area (ft2)ΔT = oil temp – ambient air temp

Pressure

P = FA ; F = P x A

P = pressure (PSI)F = force (lb.)A = area (in2)

Piston Area (cylinder)

Ap = 0.7854 ( Dp )2 Ap = piston area

Dp = piston diameter

Rod Area (cylinder)

Ar = 0.7854 ( Dr )2 Ar = rod area

Dr = rod diameter

Effective Area (cylinder)

Ae = Ap - ArAe = effective areaAp = piston areaAr = rod area

Volume (cylinder)

V = A x S V = volume (in3)A = area (in2) [note: either Ap or Ae] S = stroke (in.)

Piston Rod Speed (cylinder)

v = Q x 231A

v = piston rod speed (in/min)Q = flow (gpm)A = area (in2)

Flow (cylinder)

Q = v x A231

Q = flow (gpm)v = rod speed (in/min)A = area (in2) [note: either Ap or Ae]

Pipe Flow

V = 0.3208 x GPMA

V = velocity (ft/sec)GPM = gallons per minuteA = area (in²)

Pressure Drop in Pipes

ΔP/ft = GPM x V (SSU)18,300 x (D)4

GPM = gallons per minuteV = viscosity (SSU)D = inside diameter of pipe (in)

Torque

T = F x d T = torque (lb.-in.)F = force (lb.)d = distance (in.)

Motor Torque

T = P x Disp2π

T = motor torque (lb.-in.)P = pressure (PSI)Disp = motor displacement (in3/rev)

Motor Shaft Speed

RPM = Q x 231Disp

RPM = motor shaft speed (rpm)Q = flow (gpm)Disp = motor displacement (in3/rev)

Work

W = d x F W = work (ft.-lb.)d = distance (ft.)F = force (lb.)

Power (ft.-lb./sec)

d = distance (ft.)F = force (lb.)t = time (seconds)P = power (ft.-lb/sec)

d x Ft

P =

Cv = Q 22.48

Tabs x G

ΔP x (Po + Pa)√