Lin Engineering
MotorLab sizing suite

Direct drive motor sizing

Use simple mode for a fast inertia and torque estimate. Advanced mode includes external torques, friction, and duty cycle.

Inputs
Shape
Select the load geometry used for inertia calculation.
Axis of rotation
Rotation axis for the selected shape inertia equation.
Length L
mm
Length dimension used by thin plate and slender rod shapes.
Width / Height
mm
Width or height dimension used by shape-specific formulas.
Radius R
mm
Radius used by disk, cylinder, ring, sphere, cone, and hemisphere formulas.
Mass of load
kg
Total rotating load mass in kilograms.
Top speed
RPS
Maximum speed in revolutions per second.
Accel time
s
Time to accelerate from zero to top speed.
Rotation offset
mm
Offset from motor axis to load center of mass for parallel-axis effect.
Results
Key resultsRequired motor performance
Required continuous torque
1.448Nm
Required peak torque
1.448Nm
Required speed
180RPM

Use these results to find motors

All results

Length L

0.2

m

Width/Height

0.15

m

Radius R

0.08

m

Offset d

0

m

Angular speed

18.8

rad/s

Angular accel

37.6991

rad/s^2

Motor speed

180

RPM

I_shape

0.0384

kg*m^2

I_offset

0

kg*m^2

I_total

0.0384

kg*m^2

Accel torque

1.448

Nm
Direct drive motor sizing - Mode 1
Inputs
ItemValueUnit
ShapeThin Circular Disk
Axis of rotationZ
Length L200mm
Width / Height150mm
Radius R80mm
Mass of load12kg
Top speed3RPS
Accel time0.5s
Rotation offset0mm
Key results
ItemValueUnit
Required continuous torque1.448Nm
Required peak torque1.448Nm
Required speed180RPM
Outputs
ItemValueUnit
Length L0.2m
Width/Height0.15m
Radius R0.08m
Offset d0m
Angular speed18.8rad/s
Angular accel37.6991rad/s^2
Motor speed180RPM
I_shape0.0384kg*m^2
I_offset0kg*m^2
I_total0.0384kg*m^2
Accel torque1.448Nm