This compact, inexpensive plastic gearmotor (high-power 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.
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).
Some versions of these gearmotors are also available with an additional 1.5 mm-diameter output shaft that protrudes from the rear of the motor. This 5 mm-long rear shaft rotates at the same speed as the input to the gearbox and offers a way to add an encoder, such as our magnetic encoder for mini plastic gearmotors, to provide motor speed or position feedback:
This dynamically-sortable table can help you find the gearmotor that offers the best blend of speed, torque, and current-draw for your particular application. A more basic comparison table is available below:
@ 4.5 V
@ 4.5 V
@ 4.5 V
90° output + motor shaft
offset output + motor shaft
|1250 mA||150 RPM||25 oz-in||120:1 mini HP||120:1 mini HP||120:1 mini HP||120:1 mini HP|
|low-power||800 mA||120 RPM||20 oz-in||120:1 mini||120:1 mini||120:1 mini||120:1 mini|
|80 RPM||30 oz-in||180:1 mini||180:1 mini|
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. These gearmotors all work with our wide and tall mounting brackets for mini plastic gearmotors.
This item has a high-power motor (1250 mA stall current), a 120:1 gearbox, and a 3 mm diameter “D”-shaped output shaft that is offset from but parallel to the motor shaft. The 1.5 mm diameter motor shaft extends approximately 5 mm past the base of the motor.
|Size:||36.5 x 20 x 27.4 mm1|
|Shaft diameter:||3 mm2|
|Shaft type:||offset 3mm D|
|Typical operating voltage:||4.5 V|
|Free-run speed @ 4.5V:||150 rpm|
|Free-run current @ 4.5V:||130 mA|
|Stall current @ 4.5V:||1250 mA|
|Stall torque @ 4.5V:||25 oz·in3|
|Extended motor shaft?:||Y|