This compact, inexpensive plastic gearmotor (brushed DC motor with a 120:1 reduction gearbox) is well suited for use in small robots. While intended for operation at 4.5 V, it should run comfortably in the 3 V to 6 V range. The gearbox has a 0.38″-long, 3 mm-diameter D-shaped output shaft that is perpendicular to the motor shaft, and a built-in safety clutch helps protect the gears from excessive loads.
Key specs at 4.5 V: 120 RPM and 80 mA free-run, 20 oz-in (1.4 kg-cm) and 0.8 A stall.
These brushed DC gearmotors are compact and affordable — perfect for building a quick, miniature robot. They are intended for use at 4.5 V, though in general, these kinds of motors can run at voltages above and below this nominal voltage, so they should operate comfortably in the 3 V to 6 V range (rotation can start at voltages as low as 0.5 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor. The plastic gearbox is protected by a built-in safety clutch that will typically slip before the gear teeth can shear (typically when the load exceeds around 25 oz-in, or 2 kg-cm).
The mini plastic gearmotor family offers two output shaft orientations relative to the motor shaft (offset and 90°), two motor options (normal and high-power, or HP for short), and two gearbox options (120:1 and 180:1). The 120:1 versions are white and the 180:1 versions are yellow. Additionally, some versions of these gearmotors are available with an extended motor shaft that protrudes from the rear of the motor by approximately 4.5 mm. This second shaft has a diameter of 1.5 mm and rotates at the same speed as the input to the gearbox, offering a way to add a custom-built encoder to provide motor speed or position feedback.
Note: The stall torque values listed are approximate, and the built-in safety clutch might start slipping at lower torques.
The gearmotors in the table above all have a 3 mm diameter D-shaft output. These shafts are just like the ones on our micro metal gearmotors and are compatible with many Pololu wheels and our 3 mm universal mounting hubs. We also carry two low-power, 120:1 mini plastic gearmotors with 2 mm diameter spline outputs: 90° 2mm spline output and offset 2mm spline output.
Details for item #1124
This item has a low-power motor (800 mA stall current), a 120:1 gearbox, and a 3 mm diameter “D”-shaped output shaft that is perpendicular to the motor shaft. The motor shaft does not extend past the base of the motor.
|Dimension diagram of the mini plastic gearmotor with 90° 3mm D-shaft output (units are mm over [in]).|
This dimension diagram is also available as a downloadable pdf (75k pdf).
|Mini plastic gearmotor 90-degree 3mm D-shaft output with Pololu 90×10mm wheel.||
|Mini plastic gearmotor offset 3mm D-shaft output with Pololu wheel.||
|Mini plastic gearmotor 90-degree 3mm D-shaft output with Pololu 32×7mm wheel.|
The 120:1 gear ratio versions have white plastic bodies and the 180:1 gear ratio versions have yellow plastic bodies (see the main product picture).
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