Servo Motor Selection

Ball-screw servo selection with rotor inertia matching (OMNUC example).

Load mass M (kg)

Ball-screw pitch P (mm)

Ball-screw diameter D (mm)

Ball-screw mass MB (kg)

Friction coefficient (mu)

Load speed V (mm/s)

Stroke L (mm)

Stroke time tS (s)

Accel time tA (s)

Positioning accuracy AP (mm)

Reducer ratio G (1 = direct)load : motor

Formulas

lead  p = P / 1000            [m]
r     = p / (2π)
JB    = ½·MB·(D/2)²
JW    = m·r²
JL    = (JW + JB) / G²
Tw    = μ·m·g·r ;  TL = Tw / G
N     = 60·V / P / G         [rpm]
JM_min = JL / 30

Preliminary model (reference)

Servo Motor Selection

Result

Formulas