## Motor Selection Guide

##### Basic DATA for Calculation
 Total weight of table & work W = kgf Total mass of table & work m = kg Coefficient friction at linear motion area μ = Ball Screw Operation Efficiency η8 = 90% Pre-load Coefficient of internal friction of Nut μ0 = Ball Screw Diameter D = cm Ball Screw whole length L = cm Ball Screw Pitch P = cm Ball Screw Material Density ρ = kg/cm Travel Distance ℓ = cm Positioning Time t0 = sec Time of Acc/Dec t1 = sec
 External Force FE = kgf Gravitational acceleration g = m/sec² sin = cos = Basic Step Angle = ° Encoder Resolution = ppr Installation angle α = ˚ Gear Ratio R = Without Gearbox R=1 Gear Efficiency ηR = 90%(Without Gearbox ηR=1) Safety Ratio S = Angle Resolution Δθ = ˚ 25% of Position setting time is appropriate.
If you enter values in the yellow fields, the rest of the values are calculated automatically.
##### Operation Speed and Acceleration Calculation
 Work linearvelocity V = I = = cm/sec t0 - t1 - Ball Screw Rotation Speed ωR = (V/P) × 60 = rpm Operation Motor Revolution Velocity ωM = (V/P) × 60 = rpm Operation Motor Revolution Angular Velocity ωM = (V/P) × R × 2π = rad/sec Operating Motor Resolution Angular Acceleration = ω = ω = = rad/sec² t1 Ball Screw Acc/Dec Angular Velocity = ω = V × 2π = × 2π = rad/sec P Operating Motor Resolution Angular Acceleration = ω = ω = = rad/sec² t1
##### Motor Selection
 Just consider Rotor's Inertia Moment as J0 = 0, Motor Operation Torque TM = so, from FASTEH Motor Torque curves Operating motor revolution velocity ω8 = rpm at Operating Torque is TM = Select motor offers over N.m from curves

See Torque Curves of Selected Motor

##### Verify validation of selected motor
 From selected motor spec, need to file out inertia moment J0 J0 = gcm² = kgcm² = kgm² Motor's operating Torque re-calculation with consideration of motor inertia moment TM = × + = kgf·cm = N·m [ Verify validation of selected motor ] From selected motor's torque curve Selected motor's revolution velocity ω8 = rpm at Selected motor's torque is TM = is over : OK. Selected motor's torque is TM = is less than : NG. Repeat step 6. (Motor selection) and Step 7. (Verify Validation) width increasing motor's length or size
##### Verify validation of selected motor
 K = JL = = J0 × R² × ² Check Load's Intertia Moment Ratio K Can operate but motor's inappropriate opation (vibrating at Acc/Dec) can be happened So, please input enough Acc/Dec and need to decrease operation speed If you can't control Acc/Dec and need to decrease operation speed, please increase one level of motor's length or size, We would like to recommend to choose bigger motor has higher inertia moment. In case of using reducer, even selected motor's operation torque is enough but load inertia moment ratio "K" is not satisfied, We would like to recomment to choose incrased ration of reducer.