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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/cm³
Timing Belt Operation Efficiency	ηT =	90%
Pulley 1 Diameter(Motor side)	D_P1 =	cm
Pulley 1 Width(Motor Side)	L_P1 =	cm
Pulley 2 Diameter(Load Side)	D_P2 =	cm
Pulley 2 Width(Load Side)	L_P2 =	cm
Pulley Material Density	ρP =	kg/cm³

External Force	F_E =	kgf
Gravitational acceleration	g =	m/sec²
sin α	=
cos α	=
Installation angle	α =	˚
Travel Distance	ℓ =	cm
Positioning Time	t₀ =	sec
Time of Acc/Dec	t₁ =	sec
Gear Ratio	R =	Without Gearbox R=1
Gear Efficiency	_ηR =	90%(Without Gearbox _ηR=1)
Pulley Gear Ratio	R_p =	= D_P2/D_P1
Safety Ratio	S =
Encoder Resolution		ppr
Angle Resolution	Δθ =	˚

If you enter values in the yellow fields, the rest of the values are calculated automatically.

Refresh Calculate

Operation Speed and Acceleration Calculation

Work linearvelocity V =	I	=		= cm/sec
	t₀ - t₁		-
Ball Screw Revolution Velocity ω₈ = (V/P) × 2π = rad/sec
= rpm
Pulley2(Load Side)Revolution Velocity ω_P2 = ω_B2 = rad/sec
Pulley1(Motor Side)Revolution Velocity ω_P2 = ω_P2 × R_P = rad/sec
Operating Motor Revolution Angular Velocity ω_M = ω_P2 × R = rad/sec
= rpm
Operating Motor Resolution Angular Acceleration = ω_M =	ω_M	=		= rad/sec²
	t₁

Motor Selection


Just consider Rotor's Inertia Moment as J₀ = 0,
Motor Operation Torque	T_M =	so, from FASTEH Motor Torque curves
Operating motor revolution velocity	ω₈ =	rpm at
Operating Torque is	T_M =	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
T_M = × J₀ + kgf·cm
= × + = 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	T_M =	is over : OK.
Selected motor's torque is	T_M =	is less than : NG.
Repeat step 6. (Motor selection) and Step 7. (Verify Validation) width increasing motor's length or size

Refresh Calculate

Verify validation of selected motor


K =	J_L	=		=
	J₀ × R²		× ²

If Load's intertia moment ratio is less than 30, result is OK.
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.