Lsmin h Lsf = Length of Spring, Free condition (one spring to represent many) Lsmin = Length of Spring, MINimum (upper bearing outer ring bottomed out against housing axial seat) h = height of rotor above bottomed out (varies with Fapp) Lr = Length of motor Rotor (bottom of upper brg to top of lower brg) Lms =Length of Motor Stator (housing axial seat below upper brg to housing axial seat above lower brg) EP = End Play = Lr - Lms (endplay adjustment accomplished by varying Lms for this motor) Fapp = total APPlied Force (Weight + THrust of pump) Ru = Reaction force on rotor from Upper bearing Rb = Reaction force on rotor from Bottom bearing K = spring constant (assumed constant if Lsf-Lsmin << Lsmin) Fspring = K*(Lsf –Lsmin - h) [when not bottomed out] Static Force balance: Ru = Rb + Fapp *Simplifying assumption: all parts have stiffness much higher than springs => all others considered infinite stiffness. Lms Lr Lsf Ru Rb Fapp= W + TH h force EP Ru = K*(Lsf-Lsmin- h) Fapp force Rb = K*(Lsf-Lsmin- EP)-Fapp W K*(Lsf-Lsmin-EP) K*(Lsf-Lsmin- EP)-W Rb Fapp = K*(Lsf-Lsmin- EP) K*(Lsf-Lsmin) Endplay <=Rb with lower EP Ru <=Ru with lower EP Rb Slope=1 0 0

Inner cap Bearing Lock Washer * Outer Cap Spacer (steel) ENDPLAY ADJUST * * Bearing nut Shaft threads Shaft Centerline Lower Brg Detail - ADJUST ENDPLAY WITH PIECE 10 Bearing Bracket

Upper bearing – edited to add spring Bearing Bracket Upper and lower bearing brackets are attached to opposite ends of motor frame.